contains 313 rules |
System Settingsgroup |
contains 189 rules |
Installing and Maintaining SoftwaregroupThe following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
contains 13 rules |
Disk PartitioninggroupTo ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/, /boot, and swap.
If starting with any of the default layouts, check the box to
"Review and modify partitioning." This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making /'s logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later.If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible.
See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more
detailed information on LVM. |
contains 5 rules |
Ensure /tmp Located On Separate Partitionrule
The /tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM.
identifiers:
CCE-26435-8, DISA FSO RHEL-06-000001 references:
SC-32, 1208, Test attestation on 20120928 by MM |
Ensure /var Located On Separate PartitionruleThe /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM.
identifiers:
CCE-26639-5, DISA FSO RHEL-06-000002 references:
SC-32, 1208, Test attestation on 20120928 by MM |
Ensure /var/log Located On Separate Partitionrule
System logs are stored in the /var/log directory.
Ensure that it has its own partition or logical
volume at installation time, or migrate it using LVM.
identifiers:
CCE-26215-4, DISA FSO RHEL-06-000003 references:
AU-9, SC-32, 1208, Test attestation on 20120928 by MM |
Ensure /var/log/audit Located On Separate Partitionrule
Audit logs are stored in the /var/log/audit directory. Ensure that it
has its own partition or logical volume at installation time, or migrate it
later using LVM. Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon.
identifiers:
CCE-26436-6, DISA FSO RHEL-06-000004 references:
AU-4, AU-9, SC-32, 137, 138, 1208, Test attestation on 20120928 by MM |
Ensure /home Located On Separate Partitionrule
If user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later.
identifiers:
CCE-26557-9, DISA FSO RHEL-06-000007 references:
SC-32, 1208, Test attestation on 20120928 by MM |
Updating SoftwaregroupThe yum command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
Red Hat Enterprise Linux systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
yum or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 3 rules |
Ensure Red Hat GPG Key Installedrule
To ensure the system can cryptographically verify base software
packages come from Red Hat (and to connect to the Red Hat Network to
receive them), the Red Hat GPG key must properly be installed.
To install the Red Hat GPG key, run:
$ sudo rhn_register
If the system is not connected to the Internet or an RHN Satellite,
then install the Red Hat GPG key from trusted media such as
the Red Hat installation CD-ROM or DVD. Assuming the disc is mounted
in /media/cdrom, use the following command as the root user to import
it into the keyring:
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY
identifiers:
CCE-26506-6, DISA FSO RHEL-06-000008 references:
SI-7, MA-1(b), 351, Test attestation on 20120928 by MM Remediation script:# The two fingerprints below are retrieved from https://access.redhat.com/security/team/key
readonly REDHAT_RELEASE_2_FINGERPRINT="567E 347A D004 4ADE 55BA 8A5F 199E 2F91 FD43 1D51"
readonly REDHAT_AUXILIARY_FINGERPRINT="43A6 E49C 4A38 F4BE 9ABF 2A53 4568 9C88 2FA6 58E0"
# Location of the key we would like to import (once it's integrity verified)
readonly REDHAT_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"
RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$REDHAT_RELEASE_KEY")")
# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
# If they are safe, try to obtain fingerprints from the key file
# (to ensure there won't be e.g. CRC error)
IFS=$'\n' GPG_OUT=($(gpg --with-fingerprint "${REDHAT_RELEASE_KEY}"))
GPG_RESULT=$?
# No CRC error, safe to proceed
if [ "${GPG_RESULT}" -eq "0" ]
then
for ITEM in "${GPG_OUT[@]}"
do
# Filter just hexadecimal fingerprints from gpg's output from
# processing of a key file
RESULT=$(echo ${ITEM} | sed -n "s/[[:space:]]*Key fingerprint = \(.*\)/\1/p" | tr -s '[:space:]')
# If fingerprint matches Red Hat's release 2 or auxiliary key import the key
if [[ ${RESULT} ]] && ([[ ${RESULT} = "${REDHAT_RELEASE_2_FINGERPRINT}" ]] || \
[[ ${RESULT} = "${REDHAT_AUXILIARY_FINGERPRINT}" ]])
then
rpm --import "${REDHAT_RELEASE_KEY}"
fi
done
fi
fi
|
Ensure gpgcheck Enabled In Main Yum ConfigurationruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure yum to check package signatures before installing
them, ensure the following line appears in /etc/yum.conf in
the [main] section:
gpgcheck=1
identifiers:
CCE-26709-6, DISA FSO RHEL-06-000013 references:
SI-7, MA-1(b), 352, 663, Test attestation on 20120928 by MM |
Ensure gpgcheck Enabled For All Yum Package RepositoriesruleTo ensure signature checking is not disabled for
any repos, remove any lines from files in /etc/yum.repos.d of the form:
gpgcheck=0
identifiers:
CCE-26647-8, DISA FSO RHEL-06-000015 references:
SI-7, MA-1(b), 352, 663, Test attestation on 20120928 by MM |
Software Integrity Checkinggroup
Both the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system.
Integrity checking cannot prevent intrusions,
but can detect that they have occurred. Requirements
for software integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based
approaches such as AIDE may induce considerable overhead
in the presence of frequent software updates.
|
contains 5 rules |
Verify Integrity with AIDEgroupAIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION.
|
contains 3 rules |
Install AIDErule
Install the AIDE package with the command:
$ sudo yum install aide
identifiers:
CCE-27024-9, DISA FSO RHEL-06-000016 references:
CM-3(d), CM-3(e), CM-6(d), SC-28, SI-7, 1069, Test attestation on 20121024 by DS Remediation script:yum -y install aide
|
Disable Prelinkingrule
The prelinking feature changes binaries in an attempt to decrease their startup
time. In order to disable it, change or add the following line inside the file
/etc/sysconfig/prelink:
PRELINKING=no
Next, run the following command to return binaries to a normal, non-prelinked state:
$ sudo /usr/sbin/prelink -ua
identifiers:
CCE-27221-1 references:
CM-6(d), SC-28, SI-7 Remediation script:#
# Disable prelinking altogether
#
if grep -q ^PRELINKING /etc/sysconfig/prelink
then
sed -i 's/PRELINKING.*/PRELINKING=no/g' /etc/sysconfig/prelink
else
echo -e "\n# Set PRELINKING=no per security requirements" >> /etc/sysconfig/prelink
echo "PRELINKING=no" >> /etc/sysconfig/prelink
fi
#
# Undo previous prelink changes to binaries
#
/usr/sbin/prelink -ua
|
Build and Test AIDE DatabaseruleRun the following command to generate a new database:
$ sudo /usr/sbin/aide --init
By default, the database will be written to the file /var/lib/aide/aide.db.new.gz.
Storing the database, the configuration file /etc/aide.conf, and the binary
/usr/sbin/aide (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity.
The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
$ sudo /usr/sbin/aide --check
If this check produces any unexpected output, investigate.
identifiers:
CCE-27135-3, DISA FSO RHEL-06-000018 references:
CM-3(d), CM-3(e), CM-6(d), SC-28, SI-7, 374, 416, 1069, 1263, 1297, 1589 |
Verify Integrity with RPMgroupThe RPM package management system includes the ability
to verify the integrity of installed packages by comparing the
installed files with information about the files taken from the
package metadata stored in the RPM database. Although an attacker
could corrupt the RPM database (analogous to attacking the AIDE
database as described above), this check can still reveal
modification of important files. To list which files on the system differ from what is expected by the RPM database:
$ rpm -qVa
See the man page for rpm to see a complete explanation of each column.
|
contains 2 rules |
Verify and Correct File Permissions with RPMrule
The RPM package management system can check file access
permissions of installed software packages, including many that are
important to system security.
After locating a file with incorrect permissions, run the following command to determine which package owns it:
$ rpm -qf FILENAME
Next, run the following command to reset its permissions to
the correct values:
$ sudo rpm --setperms PACKAGENAME
identifiers:
CCE-26731-0, DISA FSO RHEL-06-000518 references:
AC-6, CM-6(d), SI-7, 1493, 1494, 1495 |
Verify File Hashes with RPMruleThe RPM package management system can check the hashes of
installed software packages, including many that are important to system
security. Run the following command to list which files on the system
have hashes that differ from what is expected by the RPM database:
$ rpm -Va | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which
may appropriately be expected to change. If the file was not expected to
change, investigate the cause of the change using audit logs or other means.
The package can then be reinstalled to restore the file.
Run the following command to determine which package owns the file:
$ rpm -qf FILENAME
The package can be reinstalled from a yum repository using the command:
$ sudo yum reinstall PACKAGENAME
Alternatively, the package can be reinstalled from trusted media using the command:
$ sudo rpm -Uvh PACKAGENAME
identifiers:
CCE-27223-7, DISA FSO RHEL-06-000519 references:
CM-6(d), SI-7, 1496 |
File Permissions and MasksgroupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
Several of the commands in this section search filesystems
for files or directories with certain characteristics, and are
intended to be run on every local partition on a given system.
When the variable PART appears in one of the commands below,
it means that the command is intended to be run repeatedly, with the
name of each local partition substituted for PART in turn.
The following command prints a list of all ext4 partitions on the local
system, which is the default filesystem for Red Hat Enterprise Linux
6 installations:
$ mount -t ext4 | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate.
|
contains 49 rules |
Restrict Partition Mount OptionsgroupSystem partitions can be mounted with certain options
that limit what files on those partitions can do. These options
are set in the /etc/fstab configuration file, and can be
used to make certain types of malicious behavior more difficult. |
contains 10 rules |
Add nodev Option to Removable Media PartitionsruleThe nodev mount option prevents files from being
interpreted as character or block devices.
Legitimate character and block devices should exist only in
the /dev directory on the root partition or within chroot
jails built for system services.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
any removable media partitions.
identifiers:
CCE-26860-7 references:
AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2 |
Add noexec Option to Removable Media PartitionsruleThe noexec mount option prevents the direct
execution of binaries on the mounted filesystem.
Preventing the direct execution of binaries from removable media (such as a USB
key) provides a defense against malicious software that may be present on such
untrusted media.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
any removable media partitions.
identifiers:
CCE-27196-5, DISA FSO RHEL-06-000271 references:
AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2, 87 |
Add nosuid Option to Removable Media PartitionsruleThe nosuid mount option prevents set-user-identifier (SUID)
and set-group-identifier (SGID) permissions from taking effect. These permissions
allow users to execute binaries with the same permissions as the owner and group
of the file respectively. Users should not be allowed to introduce SUID and SGID
files into the system via partitions mounted from removeable media.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
any removable media partitions.
identifiers:
CCE-27056-1 references:
AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2 |
Add nodev Option to /tmprule
The nodev mount option can be used to prevent device files from
being created in /tmp.
Legitimate character and block devices should not exist
within temporary directories like /tmp.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp.
identifiers:
CCE-26499-4 references:
CM-7, MP-2 |
Add noexec Option to /tmpruleThe noexec mount option can be used to prevent binaries
from being executed out of /tmp.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp.
identifiers:
CCE-26720-3 references:
CM-7, MP-2 |
Add nosuid Option to /tmpruleThe nosuid mount option can be used to prevent
execution of setuid programs in /tmp. The SUID and SGID permissions
should not be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp.
identifiers:
CCE-26762-5 references:
CM-7, MP-2 |
Add nodev Option to /dev/shmruleThe nodev mount option can be used to prevent creation
of device files in /dev/shm.
Legitimate character and block devices should not exist
within temporary directories like /dev/shm.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm.
identifiers:
CCE-26778-1 references:
CM-7, MP-2 Remediation script:
# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)
# Save the:
# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
# * 4-th field into DEV_SHM_OPTS variable, and
# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
# splitting DEV_SHM_FSTAB variable value based on the '#' separator
IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"
# Replace occurrence of 'defaults' key with the actual list of mount options
# for Red Hat Enterprise Linux 6
DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}
# 'dev' option (not prefixed with 'no') present in the list?
echo $DEV_SHM_OPTS | grep -q -P '(?<!no)dev'
if [ $? -eq 0 ]
then
# 'dev' option found, replace with 'nodev'
DEV_SHM_OPTS=${DEV_SHM_OPTS//dev/nodev}
fi
# at least one 'nodev' present in the options list?
echo $DEV_SHM_OPTS | grep -q -v 'nodev'
if [ $? -eq 0 ]
then
# 'nodev' not found yet, append it
DEV_SHM_OPTS="$DEV_SHM_OPTS,nodev"
fi
# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
# in /etc/fstab with the corrected version
sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab
|
Add noexec Option to /dev/shmruleThe noexec mount option can be used to prevent binaries
from being executed out of /dev/shm.
It can be dangerous to allow the execution of binaries
from world-writable temporary storage directories such as /dev/shm.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm.
identifiers:
CCE-26622-1 references:
CM-7, MP-2 Remediation script:
# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)
# Save the:
# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
# * 4-th field into DEV_SHM_OPTS variable, and
# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
# splitting DEV_SHM_FSTAB variable value based on the '#' separator
IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"
# Replace occurrence of 'defaults' key with the actual list of mount options
# for Red Hat Enterprise Linux 6
DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}
# 'exec' option (not prefixed with 'no') present in the list?
echo $DEV_SHM_OPTS | grep -q -P '(?<!no)exec'
if [ $? -eq 0 ]
then
# 'exec' option found, replace with 'noexec'
DEV_SHM_OPTS=${DEV_SHM_OPTS//exec/noexec}
fi
# at least one 'noexec' present in the options list?
echo $DEV_SHM_OPTS | grep -q -v 'noexec'
if [ $? -eq 0 ]
then
# 'noexec' not found yet, append it
DEV_SHM_OPTS="$DEV_SHM_OPTS,noexec"
fi
# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
# in /etc/fstab with the corrected version
sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab
|
Add nosuid Option to /dev/shmruleThe nosuid mount option can be used to prevent execution
of setuid programs in /dev/shm. The SUID and SGID permissions should not
be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm.
identifiers:
CCE-26486-1 references:
CM-7, MP-2 Remediation script:
# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)
# Save the:
# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
# * 4-th field into DEV_SHM_OPTS variable, and
# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
# splitting DEV_SHM_FSTAB variable value based on the '#' separator
IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"
# Replace occurrence of 'defaults' key with the actual list of mount options
# for Red Hat Enterprise Linux 6
DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}
# 'suid' option (not prefixed with 'no') present in the list?
echo $DEV_SHM_OPTS | grep -q -P '(?<!no)suid'
if [ $? -eq 0 ]
then
# 'suid' option found, replace with 'nosuid'
DEV_SHM_OPTS=${DEV_SHM_OPTS//suid/nosuid}
fi
# at least one 'nosuid' present in the options list?
echo $DEV_SHM_OPTS | grep -q -v 'nosuid'
if [ $? -eq 0 ]
then
# 'nosuid' not found yet, append it
DEV_SHM_OPTS="$DEV_SHM_OPTS,nosuid"
fi
# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
# in /etc/fstab with the corrected version
sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab
|
Bind Mount /var/tmp To /tmpruleThe /var/tmp directory is a world-writable directory.
Bind-mount it to /tmp in order to consolidate temporary storage into
one location protected by the same techniques as /tmp. To do so, edit
/etc/fstab and add the following line:
/tmp /var/tmp none rw,nodev,noexec,nosuid,bind 0 0
See the mount(8) man page for further explanation of bind mounting.
identifiers:
CCE-26582-7 references:
CM-7 Remediation script:# Delete particular /etc/fstab's row if /var/tmp is already configured to
# represent a mount point (for some device or filesystem other than /tmp)
if grep -q -P '.*\/var\/tmp.*' /etc/fstab
then
sed -i '/.*\/var\/tmp.*/d' /etc/fstab
fi
# Bind-mount /var/tmp to /tmp via /etc/fstab (preserving the /etc/fstab form)
printf "%-24s%-24s%-8s%-32s%-3s\n" "/tmp" "/var/tmp" "none" "rw,nodev,noexec,nosuid,bind" "0 0" >> /etc/fstab
|
Restrict Dynamic Mounting and Unmounting of
FilesystemsgroupLinux includes a number of facilities for the automated addition
and removal of filesystems on a running system. These facilities may be
necessary in many environments, but this capability also carries some risk -- whether direct
risk from allowing users to introduce arbitrary filesystems,
or risk that software flaws in the automated mount facility itself could
allow an attacker to compromise the system.
This command can be used to list the types of filesystems that are
available to the currently executing kernel:
$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled
in a configuratio file in /etc/modprobe.d.
|
contains 12 rules |
Disable Modprobe Loading of USB Storage Driverrule
To prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.
To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually. identifiers:
CCE-27016-5, DISA FSO RHEL-06-000503 references:
AC-19(a), AC-19(d), AC-19(e), 1250, 85 Remediation script:echo "install usb-storage /bin/true" > /etc/modprobe.d/usb-storage.conf
|
Disable Kernel Support for USB via Bootloader Configurationrule
All USB support can be disabled by adding the nousb
argument to the kernel's boot loader configuration. To do so,
append "nousb" to the kernel line in /etc/grub.conf as shown:
kernel /vmlinuz-VERSION ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet nousb
WARNING: Disabling all kernel support for USB will cause problems for
systems with USB-based keyboards, mice, or printers. This configuration is
infeasible for systems which require USB devices, which is common. identifiers:
CCE-27011-6 references:
AC-19(a), AC-19(d), AC-19(e), 1250 |
Disable the AutomounterruleThe autofs daemon mounts and unmounts filesystems, such as user
home directories shared via NFS, on demand. In addition, autofs can be used to handle
removable media, and the default configuration provides the cdrom device as /misc/cd.
However, this method of providing access to removable media is not common, so autofs
can almost always be disabled if NFS is not in use. Even if NFS is required, it may be
possible to configure filesystem mounts statically by editing /etc/fstab
rather than relying on the automounter.
The autofs service can be disabled with the following command:
$ sudo chkconfig autofs off
identifiers:
CCE-26976-1, DISA FSO RHEL-06-000526 references:
AC-19(a), AC-19(d), AC-19(e), 1250, 85 Remediation script:#
# Disable autofs for all run levels
#
/sbin/chkconfig --level 0123456 autofs off
#
# Stop autofs if currently running
#
/sbin/service autofs stop
|
Disable GNOME AutomountingruleThe system's default desktop environment, GNOME, will mount
devices and removable media (such as DVDs, CDs and USB flash drives) whenever
they are inserted into the system. Disable automount and autorun within GNOME
by running the following:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/nautilus/preferences/media_automount false
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/nautilus/preferences/media_autorun_never true
identifiers:
CCE-27035-5 references:
AC-19(a), AC-19(d), AC-19(e) |
Disable Mounting of cramfsrule
To configure the system to prevent the cramfs
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install cramfs /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26340-0 references:
CM-7 Remediation script:echo "install cramfs /bin/true" > /etc/modprobe.d/cramfs.conf
|
Disable Mounting of freevxfsrule
To configure the system to prevent the freevxfs
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install freevxfs /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26544-7 references:
CM-7 Remediation script:echo "install freevxfs /bin/true" > /etc/modprobe.d/freevxfs.conf
|
Disable Mounting of jffs2rule
To configure the system to prevent the jffs2
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install jffs2 /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26670-0 references:
CM-7 Remediation script:echo "install jffs2 /bin/true" > /etc/modprobe.d/jffs2.conf
|
Disable Mounting of hfsrule
To configure the system to prevent the hfs
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install hfs /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26800-3 references:
CM-7 Remediation script:echo "install hfs /bin/true" > /etc/modprobe.d/hfs.conf
|
Disable Mounting of hfsplusrule
To configure the system to prevent the hfsplus
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install hfsplus /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26361-6 references:
CM-7 Remediation script:echo "install hfsplus /bin/true" > /etc/modprobe.d/hfsplus.conf
|
Disable Mounting of squashfsrule
To configure the system to prevent the squashfs
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install squashfs /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26404-4 references:
CM-7 Remediation script:echo "install squashfs /bin/true" > /etc/modprobe.d/squashfs.conf
|
Disable Mounting of udfrule
To configure the system to prevent the udf
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install udf /bin/true
This effectively prevents usage of this uncommon filesystem.
identifiers:
CCE-26677-5 references:
CM-7 Remediation script:echo "install udf /bin/true" > /etc/modprobe.d/udf.conf
|
Disable All GNOME ThumbnailersruleThe system's default desktop environment, GNOME, uses
a number of different thumbnailer programs to generate thumbnails
for any new or modified content in an opened folder. The following
command can disable the execution of these thumbnail applications:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /desktop/gnome/thumbnailers/disable_all true
This effectively prevents an attacker from gaining access to a
system through a flaw in GNOME's Nautilus thumbnail creators.
identifiers:
CCE-27224-5 references:
CM-7 |
Verify Permissions on Important Files and
DirectoriesgroupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses important
permission restrictions which can be verified
to ensure that no harmful discrepancies have
arisen. |
contains 21 rules |
Verify Permissions on Files with Local Account Information and CredentialsgroupThe default restrictive permissions for files which act as
important security databases such as passwd, shadow,
group, and gshadow files must be maintained. Many utilities
need read access to the passwd file in order to function properly, but
read access to the shadow file allows malicious attacks against system
passwords, and should never be enabled. |
contains 12 rules |
Verify User Who Owns shadow Filerule
To properly set the owner of /etc/shadow, run the command:
$ sudo chown root /etc/shadow
identifiers:
CCE-26947-2, DISA FSO RHEL-06-000033 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chown root /etc/shadow
|
Verify Group Who Owns shadow Filerule
To properly set the group owner of /etc/shadow, run the command:
$ sudo chgrp root /etc/shadow
identifiers:
CCE-26967-0, DISA FSO RHEL-06-000034 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chgrp root /etc/shadow
|
Verify Permissions on shadow Filerule
To properly set the permissions of /etc/shadow, run the command:
$ sudo chmod 0000 /etc/shadow
identifiers:
CCE-26992-8, DISA FSO RHEL-06-000035 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chmod 0000 /etc/shadow
|
Verify User Who Owns group Filerule
To properly set the owner of /etc/group, run the command:
$ sudo chown root /etc/group
identifiers:
CCE-26822-7, DISA FSO RHEL-06-000042 references:
AC-6, Test attestation on 20121026 by DS Remediation script:chown root /etc/group
|
Verify Group Who Owns group Filerule
To properly set the group owner of /etc/group, run the command:
$ sudo chgrp root /etc/group
identifiers:
CCE-26930-8, DISA FSO RHEL-06-000043 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chgrp root /etc/group
|
Verify Permissions on group Filerule
To properly set the permissions of /etc/group, run the command:
$ sudo chmod 644 /etc/group
identifiers:
CCE-26954-8, DISA FSO RHEL-06-000044 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chmod 644 /etc/group
|
Verify User Who Owns gshadow Filerule
To properly set the owner of /etc/gshadow, run the command:
$ sudo chown root /etc/gshadow
identifiers:
CCE-27026-4, DISA FSO RHEL-06-000036 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chown root /etc/gshadow
|
Verify Group Who Owns gshadow Filerule
To properly set the group owner of /etc/gshadow, run the command:
$ sudo chgrp root /etc/gshadow
identifiers:
CCE-26975-3, DISA FSO RHEL-06-000037 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chgrp root /etc/gshadow
|
Verify Permissions on gshadow Filerule
To properly set the permissions of /etc/gshadow, run the command:
$ sudo chmod 0000 /etc/gshadow
identifiers:
CCE-26951-4, DISA FSO RHEL-06-000038 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chmod 0000 /etc/gshadow
|
Verify User Who Owns passwd Filerule
To properly set the owner of /etc/passwd, run the command:
$ sudo chown root /etc/passwd
identifiers:
CCE-26953-0, DISA FSO RHEL-06-000039 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chown root /etc/passwd
|
Verify Group Who Owns passwd Filerule
To properly set the group owner of /etc/passwd, run the command:
$ sudo chgrp root /etc/passwd
identifiers:
CCE-26856-5, DISA FSO RHEL-06-000040 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chgrp root /etc/passwd
|
Verify Permissions on passwd Filerule
To properly set the permissions of /etc/passwd, run the command:
$ sudo chmod 0644 /etc/passwd
identifiers:
CCE-26868-0, DISA FSO RHEL-06-000041 references:
AC-6, 225, Test attestation on 20121026 by DS Remediation script:chmod 0644 /etc/passwd
|
Verify File Permissions Within Some Important DirectoriesgroupSome directories contain files whose confidentiality or integrity
is notably important and may also be susceptible to misconfiguration over time, particularly if
unpackaged software is installed. As such,
an argument exists to verify that files' permissions within these directories remain
configured correctly and restrictively.
|
contains 4 rules |
Verify that Shared Library Files Have Restrictive PermissionsruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are
stored in /lib/modules. All files in these directories
should not be group-writable or world-writable. If any file in these
directories is found to be group-writable or world-writable, correct
its permission with the following command:
$ sudo chmod go-w FILE
identifiers:
CCE-27381-3, DISA FSO RHEL-06-000045 references:
AC-6, 1499, Test attestation on 20121026 by DS Remediation script:DIRS="/lib /lib64 /usr/lib /usr/lib64"
for dirPath in $DIRS; do
find $dirPath -perm /022 -type f -exec chmod go-w '{}' \;
done
|
Verify that Shared Library Files Have Root OwnershipruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also
stored in /lib/modules. All files in these directories should be
owned by the root user. If the directory, or any file in these
directories, is found to be owned by a user other than root correct its
ownership with the following command:
$ sudo chown root FILE
identifiers:
CCE-27424-1, DISA FSO RHEL-06-000046 references:
AC-6, 1499, Test attestation on 20130914 by swells Remediation script:for LIBDIR in /usr/lib /usr/lib64 /lib /lib64
do
if [ -d $LIBDIR ]
then
find -L $LIBDIR \! -user root -exec chown root {} \;
fi
done
|
Verify that System Executables Have Restrictive Permissionsrule
System executables are stored in the following directories by default:
/bin
/usr/bin
/usr/local/bin
/sbin
/usr/sbin
/usr/local/sbin
All files in these directories should not be group-writable or world-writable.
If any file FILE in these directories is found
to be group-writable or world-writable, correct its permission with the
following command:
$ sudo chmod go-w FILE
identifiers:
CCE-27289-8, DISA FSO RHEL-06-000047 references:
AC-6, 1499 Remediation script:DIRS="/bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin"
for dirPath in $DIRS; do
find $dirPath -perm /022 -exec chmod go-w '{}' \;
done
|
Verify that System Executables Have Root Ownershiprule
System executables are stored in the following directories by default:
/bin
/usr/bin
/usr/local/bin
/sbin
/usr/sbin
/usr/local/sbin
All files in these directories should be owned by the root user.
If any file FILE in these directories is found
to be owned by a user other than root, correct its ownership with the
following command:
$ sudo chown root FILE
identifiers:
CCE-27623-8, DISA FSO RHEL-06-000048 references:
AC-6, 1499 Remediation script:find /bin/ \
/usr/bin/ \
/usr/local/bin/ \
/sbin/ \
/usr/sbin/ \
/usr/local/sbin/ \
\! -user root -execdir chown root {} \;
|
Verify that All World-Writable Directories Have Sticky Bits SetruleWhen the so-called 'sticky bit' is set on a directory,
only the owner of a given file may remove that file from the
directory. Without the sticky bit, any user with write access to a
directory may remove any file in the directory. Setting the sticky
bit prevents users from removing each other's files. In cases where
there is no reason for a directory to be world-writable, a better
solution is to remove that permission rather than to set the sticky
bit. However, if a directory is used by a particular application,
consult that application's documentation instead of blindly
changing modes.
To set the sticky bit on a world-writable directory DIR, run the
following command:
$ sudo chmod +t DIR
identifiers:
CCE-26840-9, DISA FSO RHEL-06-000336 references:
AC-6, Test attestation on 20120929 by swells Remediation script:df --local -P | awk {'if (NR!=1) print $6'} \
| xargs -I '{}' find '{}' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
| xargs chmod a+t
|
Ensure No World-Writable Files ExistruleIt is generally a good idea to remove global (other) write
access to a file when it is discovered. However, check with
documentation for specific applications before making changes.
Also, monitor for recurring world-writable files, as these may be
symptoms of a misconfigured application or user
account. identifiers:
CCE-26910-0, DISA FSO RHEL-06-000282 references:
AC-6 |
Ensure All Files Are Owned by a UserruleIf any files are not owned by a user, then the
cause of their lack of ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate user.
identifiers:
CCE-27032-2 references:
AC-6, 224 |
Ensure All Files Are Owned by a GroupruleIf any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group.
identifiers:
CCE-26872-2 references:
AC-6, 224 |
Ensure All World-Writable Directories Are Owned by a System AccountruleAll directories in local partitions which are
world-writable should be owned by root or another
system account. If any world-writable directories are not
owned by a system account, this should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group.
identifiers:
CCE-26642-9, DISA FSO RHEL-06-000337 references:
AC-6, Test attestation on 20120929 by swells |
Restrict Programs from Dangerous Execution PatternsgroupThe recommendations in this section are designed to
ensure that the system's features to protect against potentially
dangerous program execution are activated.
These protections are applied at the system initialization or
kernel level, and defend against certain types of badly-configured
or compromised programs. |
contains 6 rules |
Daemon UmaskgroupThe umask is a per-process setting which limits
the default permissions for creation of new files and directories.
The system includes initialization scripts which set the default umask
for system daemons.
|
contains 1 rule |
Set Daemon UmaskruleThe file /etc/init.d/functions includes initialization
parameters for most or all daemons started at boot time. The default umask of
022 prevents creation of group- or world-writable files. To set the default
umask for daemons, edit the following line, inserting 022 or 027 for
umask appropriately:
umask 027
Setting the umask to too restrictive a setting can cause serious errors at
runtime. Many daemons on the system already individually restrict themselves to
a umask of 077 in their own init scripts.
identifiers:
CCE-27031-4, DISA FSO RHEL-06-000346 references:
AC-6, Test attestation on 20140912 by JL Remediation script:var_umask_for_daemons="027"
grep -q ^umask /etc/init.d/functions && \
sed -i "s/umask.*/umask $var_umask_for_daemons/g" /etc/init.d/functions
if ! [ $? -eq 0 ]; then
echo "umask $var_umask_for_daemons" >> /etc/init.d/functions
fi
|
Disable Core DumpsgroupA core dump file is the memory image of an executable
program when it was terminated by the operating system due to
errant behavior. In most cases, only software developers
legitimately need to access these files. The core dump files may
also contain sensitive information, or unnecessarily occupy large
amounts of disk space.
Once a hard limit is set in /etc/security/limits.conf, a
user cannot increase that limit within his or her own session. If access
to core dumps is required, consider restricting them to only
certain users or groups. See the limits.conf man page for more
information.
The core dumps of setuid programs are further protected. The
sysctl variable fs.suid_dumpable controls whether
the kernel allows core dumps from these programs at all. The default
value of 0 is recommended. |
contains 2 rules |
Disable Core Dumps for All UsersruleTo disable core dumps for all users, add the following line to
/etc/security/limits.conf:
* hard core 0
identifiers:
CCE-27033-0, DISA FSO RHEL-06-000308 references:
SC-5 Remediation script:echo "* hard core 0" >> /etc/security/limits.conf
|
Disable Core Dumps for SUID programsrule
To set the runtime status of the fs.suid_dumpable kernel parameter,
run the following command:
$ sudo sysctl -w fs.suid_dumpable=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
fs.suid_dumpable = 0
identifiers:
CCE-27044-7 references:
SI-11 Remediation script:#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable=0
#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
# else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
if grep --silent ^fs.suid_dumpable /etc/sysctl.conf ; then
sed -i 's/^fs.suid_dumpable.*/fs.suid_dumpable = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set fs.suid_dumpable to 0 per security requirements" >> /etc/sysctl.conf
echo "fs.suid_dumpable = 0" >> /etc/sysctl.conf
fi
|
Enable ExecShieldgroupExecShield describes kernel features that provide
protection against exploitation of memory corruption errors such as buffer
overflows. These features include random placement of the stack and other
memory regions, prevention of execution in memory that should only hold data,
and special handling of text buffers. These protections are enabled by default and
controlled through sysctl variables kernel.exec-shield and
kernel.randomize_va_space.
|
contains 2 rules |
Enable ExecShieldrule
To set the runtime status of the kernel.exec-shield kernel parameter,
run the following command:
$ sudo sysctl -w kernel.exec-shield=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
kernel.exec-shield = 1
identifiers:
CCE-27007-4, DISA FSO RHEL-06-000079 references:
SC-39, 2530, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for kernel.exec-shield
#
/sbin/sysctl -q -n -w kernel.exec-shield=1
#
# If kernel.exec-shield present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.exec-shield = 1" to /etc/sysctl.conf
#
if grep --silent ^kernel.exec-shield /etc/sysctl.conf ; then
sed -i 's/^kernel.exec-shield.*/kernel.exec-shield = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set kernel.exec-shield to 1 per security requirements" >> /etc/sysctl.conf
echo "kernel.exec-shield = 1" >> /etc/sysctl.conf
fi
|
Enable Randomized Layout of Virtual Address Spacerule
To set the runtime status of the kernel.randomize_va_space kernel parameter,
run the following command:
$ sudo sysctl -w kernel.randomize_va_space=2
If this is not the system's default value, add the following line to /etc/sysctl.conf:
kernel.randomize_va_space = 2
identifiers:
CCE-26999-3, DISA FSO RHEL-06-000078 references:
SC-30(2), Test attestation on 20121024 by DS Remediation script:#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space=2
#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
# else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
if grep --silent ^kernel.randomize_va_space /etc/sysctl.conf ; then
sed -i 's/^kernel.randomize_va_space.*/kernel.randomize_va_space = 2/g' /etc/sysctl.conf
else
echo -e "\n# Set kernel.randomize_va_space to 2 per security requirements" >> /etc/sysctl.conf
echo "kernel.randomize_va_space = 2" >> /etc/sysctl.conf
fi
|
Enable Execute Disable (XD) or No Execute (NX) Support on
x86 SystemsgroupRecent processors in the x86 family support the
ability to prevent code execution on a per memory page basis.
Generically and on AMD processors, this ability is called No
Execute (NX), while on Intel processors it is called Execute
Disable (XD). This ability can help prevent exploitation of buffer
overflow vulnerabilities and should be activated whenever possible.
Extra steps must be taken to ensure that this protection is
enabled, particularly on 32-bit x86 systems. Other processors, such
as Itanium and POWER, have included such support since inception
and the standard kernel for those platforms supports the
feature. |
contains 1 rule |
Install PAE Kernel on Supported 32-bit x86 SystemsruleSystems that are using the 64-bit x86 kernel package
do not need to install the kernel-PAE package because the 64-bit
x86 kernel already includes this support. However, if the system is
32-bit and also supports the PAE and NX features as
determined in the previous section, the kernel-PAE package should
be installed to enable XD or NX support:
$ sudo yum install kernel-PAE
The installation process should also have configured the
bootloader to load the new kernel at boot. Verify this at reboot
and modify /etc/grub.conf if necessary. identifiers:
CCE-27010-8 references:
CM-6(b) |
SELinuxgroupSELinux is a feature of the Linux kernel which can be
used to guard against misconfigured or compromised programs.
SELinux enforces the idea that programs should be limited in what
files they can access and what actions they can take.
The default SELinux policy, as configured on Red Hat Enterprise Linux 6, has been
sufficiently developed and debugged that it should be usable on
almost any Red Hat machine with minimal configuration and a small
amount of system administrator training. This policy prevents
system services - including most of the common network-visible
services such as mail servers, FTP servers, and DNS servers - from
accessing files which those services have no valid reason to
access. This action alone prevents a huge amount of possible damage
from network attacks against services, from trojaned software, and
so forth.
This guide recommends that SELinux be enabled using the
default (targeted) policy on every Red Hat system, unless that
system has unusual requirements which make a stronger policy
appropriate.
|
contains 5 rules |
Ensure SELinux State is EnforcingruleThe SELinux state should be set to enforcing at
system boot time. In the file /etc/selinux/config, add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=enforcing
identifiers:
CCE-26969-6, DISA FSO RHEL-06-000020 references:
AC-3, AC-3(3), AC-4, AC-6, AU-9, 22, 32, 26, Test attestation on 20121024 by DS Remediation script:var_selinux_state="enforcing"
grep -q ^SELINUX= /etc/selinux/config && \
sed -i "s/SELINUX=.*/SELINUX=$var_selinux_state/g" /etc/selinux/config
if ! [ $? -eq 0 ]; then
echo "SELINUX=$var_selinux_state" >> /etc/selinux/config
fi
|
Configure SELinux PolicyruleThe SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config:
SELINUXTYPE=targeted
Other policies, such as mls, provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases.
identifiers:
CCE-26875-5, DISA FSO RHEL-06-000023 references:
AC-3, AC-3(3), AC-4, AC-6, AU-9, 22, 32, Test attestation on 20121024 by DS Remediation script:var_selinux_policy_name="targeted"
grep -q ^SELINUXTYPE /etc/selinux/config && \
sed -i "s/SELINUXTYPE=.*/SELINUXTYPE=$var_selinux_policy_name/g" /etc/selinux/config
if ! [ $? -eq 0 ]; then
echo "SELINUXTYPE=$var_selinux_policy_name" >> /etc/selinux/config
fi
|
Enable the SELinux Context Restoration Service (restorecond)ruleThe restorecond service utilizes inotify to look
for the creation of new files listed in the
/etc/selinux/restorecond.conf configuration file. When a file is
created, restorecond ensures the file receives the proper SELinux
security context.
The restorecond service can be enabled with the following command:
$ sudo chkconfig --level 2345 restorecond on
identifiers:
CCE-26991-0 references:
AC-3, AC-3(3), AC-4, AC-6, AU-9 Remediation script:#
# Enable restorecond for all run levels
#
/sbin/chkconfig --level 0123456 restorecond on
#
# Start restorecond if not currently running
#
/sbin/service restorecond start
|
Ensure No Daemons are Unconfined by SELinuxrule
Daemons for which the SELinux policy does not contain rules will inherit the
context of the parent process. Because daemons are launched during
startup and descend from the init process, they inherit the initrc_t context.
To check for unconfined daemons, run the following command:
$ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'
It should produce no output in a well-configured system.
identifiers:
CCE-27111-4 references:
AC-6, AU-9, CM-7 |
Ensure No Device Files are Unlabeled by SELinuxruleDevice files, which are used for communication with important
system resources, should be labeled with proper SELinux types. If any device
files carry the SELinux type unlabeled_t, investigate the cause and
correct the file's context.
identifiers:
CCE-26774-0, DISA FSO RHEL-06-000025 references:
AC-6, AU-9, CM-7, 22, 32, Test attestation on 20121024 by DS |
Account and Access ControlgroupIn traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
Red Hat Enterprise Linux 6. |
contains 47 rules |
Protect Accounts by Restricting Password-Based LogingroupConventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
contains 15 rules |
Restrict Root Loginsgroup
Direct root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/*.
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH.
|
contains 5 rules |
Direct root Logins Not AllowedruleTo further limit access to the root account, administrators
can disable root logins at the console by editing the /etc/securetty file.
This file lists all devices the root user is allowed to login to. If the file does
not exist at all, the root user can login through any communication device on the
system, whether via the console or via a raw network interface. This is dangerous
as user can login to his machine as root via Telnet, which sends the password in
plain text over the network. By default, Red Hat Enteprise Linux's
/etc/securetty file only allows the root user to login at the console
physically attached to the machine. To prevent root from logging in, remove the
contents of this file. To prevent direct root logins, remove the contents of this
file by typing the following command:
$ sudo echo > /etc/securetty
identifiers:
CCE-26891-2 references:
IA-2(1), Test attestation on 20121024 by DS |
Restrict Virtual Console Root Loginsrule
To restrict root logins through the (deprecated) virtual console devices,
ensure lines of this form do not appear in /etc/securetty:
vc/1
vc/2
vc/3
vc/4
identifiers:
CCE-26855-7, DISA FSO RHEL-06-000027 references:
AC-6(2), 770, Test attestation on 20121024 by DS Remediation script:sed -i '/^vc\//d' /etc/securetty
|
Ensure that System Accounts Do Not Run a Shell Upon Loginrule
Some accounts are not associated with a human
user of the system, and exist to perform some administrative
function. Should an attacker be able to log into these accounts,
they should not be granted access to a shell.
The login shell for each local account is stored in the last field of each line
in /etc/passwd. System accounts are those user accounts with a user ID less than
500. The user ID is stored in the third field.
If any system account SYSACCT (other than root) has a login shell,
disable it with the command:
$ sudo usermod -s /sbin/nologin SYSACCT
identifiers:
CCE-26966-2 references:
AC-2, 178, Test attestation on 20121024 by DS |
Verify Only Root Has UID 0rule
If any account other than root has a UID of 0,
this misconfiguration should be investigated and the
accounts other than root should be removed or have their UID changed.
identifiers:
CCE-26971-2, DISA FSO RHEL-06-000032 references:
AC-6, IA-2(1), 366, Test attestation on 20121024 by DS Remediation script:awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs passwd -l
|
Root Path Must Be Vendor Defaultrule
Assuming root shell is bash, edit the following files:
~/.profile
~/.bashrc
Change any PATH variables to the vendor default for root and remove any
empty PATH entries or references to relative paths.
identifiers:
CCE-27125-4 references:
SA-8, Test attestation on 20121024 by DS |
Verify Proper Storage and Existence of Password
Hashesgroup
By default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow. This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd, or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration.
|
contains 4 rules |
Prevent Log In to Accounts With Empty PasswordruleIf an account is configured for password authentication
but does not have an assigned password, it may be possible to log
onto the account without authentication. Remove any instances of the nullok
option in /etc/pam.d/system-auth to
prevent logins with empty passwords.
identifiers:
CCE-27038-9, DISA FSO RHEL-06-000030 references:
IA-5(b), IA-5(c), IA-5(1)(a), Test attestation on 20121024 by DS Remediation script:sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth
|
Verify All Account Password Hashes are Shadowedrule
If any password hashes are stored in /etc/passwd (in the second field,
instead of an x), the cause of this misconfiguration should be
investigated. The account should have its password reset and the hash should be
properly stored, or the account should be deleted entirely.
identifiers:
CCE-26476-2, DISA FSO RHEL-06-000031 references:
IA-5(h), 201, Test attestation on 20121024 by DS |
All GIDs referenced in /etc/passwd must be defined in /etc/grouprule
Add a group to the system for each GID referenced without a corresponding group.
identifiers:
CCE-27379-7, DISA FSO RHEL-06-000294 references:
366, Test attestation on 20121024 by DS |
Verify No netrc Files ExistruleThe .netrc files contain login information
used to auto-login into FTP servers and reside in the user's home
directory. These files may contain unencrypted passwords to
remote FTP servers making them susceptible to access by unauthorized
users and should not be used. Any .netrc files should be removed.
identifiers:
CCE-27225-2, DISA FSO RHEL-06-000347 references:
IA-5(h), AC-3, 196 |
Set Password Expiration ParametersgroupThe file /etc/login.defs controls several
password-related settings. Programs such as passwd,
su, and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS (-m) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE (-W) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER
|
contains 4 rules |
Set Password Minimum Length in login.defsruleTo specify password length requirements for new accounts,
edit the file /etc/login.defs and add or correct the following
lines:
PASS_MIN_LEN 14
The DoD requirement is 14.
The FISMA requirement is 12.
If a program consults /etc/login.defs and also another PAM module
(such as pam_cracklib) during a password change operation,
then the most restrictive must be satisfied. See PAM section
for more information about enforcing password quality requirements.
identifiers:
CCE-27002-5, DISA FSO RHEL-06-000050 references:
IA-5(f), IA-5(1)(a), 205, Test attestation on 20121026 by DS Remediation script:var_accounts_password_minlen_login_defs="14"
grep -q ^PASS_MIN_LEN /etc/login.defs && \
sed -i "s/PASS_MIN_LEN.*/PASS_MIN_LEN $var_accounts_password_minlen_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MIN_LEN $var_accounts_password_minlen_login_defs" >> /etc/login.defs
fi
|
Set Password Minimum AgeruleTo specify password minimum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MIN_DAYS 1
A value of 1 day is considered for sufficient for many
environments.
The DoD requirement is 1.
identifiers:
CCE-27013-2, DISA FSO RHEL-06-000051 references:
IA-5(f), IA-5(1)(d), 198, Test attestation on 20121026 by DS Remediation script:var_accounts_minimum_age_login_defs="1"
grep -q ^PASS_MIN_DAYS /etc/login.defs && \
sed -i "s/PASS_MIN_DAYS.*/PASS_MIN_DAYS $var_accounts_minimum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MIN_DAYS $var_accounts_minimum_age_login_defs" >> /etc/login.defs
fi
|
Set Password Maximum AgeruleTo specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 180
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
identifiers:
CCE-26985-2, DISA FSO RHEL-06-000053 references:
IA-5(f), IA-5(g), IA-5(1)(d), 180, 199, 76, Test attestation on 20121026 by DS Remediation script:var_accounts_maximum_age_login_defs="180"
grep -q ^PASS_MAX_DAYS /etc/login.defs && \
sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS $var_accounts_maximum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MAX_DAYS $var_accounts_maximum_age_login_defs" >> /etc/login.defs
fi
|
Set Password Warning AgeruleTo specify how many days prior to password
expiration that a warning will be issued to users,
edit the file /etc/login.defs and add or correct
the following line:
PASS_WARN_AGE 7
The DoD requirement is 7.
identifiers:
CCE-26988-6, DISA FSO RHEL-06-000054 references:
AC-2(2), IA-5(f), Test attestation on 20121026 by DS Remediation script:var_accounts_password_warn_age_login_defs="7"
grep -q ^PASS_WARN_AGE /etc/login.defs && \
sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE $var_accounts_password_warn_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_WARN_AGE $var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi
|
Set Account Expiration ParametersgroupAccounts can be configured to be automatically disabled
after a certain time period,
meaning that they will require administrator interaction to become usable again.
Expiration of accounts after inactivity can be set for all accounts by default
and also on a per-account basis, such as for accounts that are known to be temporary.
To configure automatic expiration of an account following
the expiration of its password (that is, after the password has expired and not been changed),
run the following command, substituting NUM_DAYS and USER appropriately:
$ sudo chage -I NUM_DAYS USER
Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the
-E option.
The file /etc/default/useradd controls
default settings for all newly-created accounts created with the system's
normal command line utilities.
|
contains 2 rules |
Set Account Expiration Following InactivityruleTo specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following lines in /etc/default/useradd, substituting
NUM_DAYS appropriately:
INACTIVE=UNDEFINED_SUB
A value of 35 is recommended.
If a password is currently on the
verge of expiration, then 35 days remain until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 95
days could elapse until the account would be automatically disabled. See the
useradd man page for more information. Determining the inactivity
timeout must be done with careful consideration of the length of a "normal"
period of inactivity for users in the particular environment. Setting
the timeout too low incurs support costs and also has the potential to impact
availability of the system to legitimate users.
identifiers:
CCE-27283-1, DISA FSO RHEL-06-000334 references:
AC-2(2), AC-2(3), 16, 17, 795 Remediation script:var_account_disable_post_pw_expiration="35"
grep -q ^INACTIVE /etc/default/useradd && \
sed -i "s/INACTIVE.*/INACTIVE=$var_account_disable_post_pw_expiration/g" /etc/default/useradd
if ! [ $? -eq 0 ]; then
echo "INACTIVE=$var_account_disable_post_pw_expiration" >> /etc/default/useradd
fi
|
Ensure All Accounts on the System Have Unique Namesrule
Change usernames, or delete accounts, so each has a unique name.
identifiers:
CCE-27609-7, DISA FSO RHEL-06-000296 references:
770, 804 |
Protect Accounts by Configuring PAMgroupPAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth. This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. |
contains 11 rules |
Set Password Quality RequirementsgroupThe default pam_cracklib PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes.
The pam_passwdqc PAM module also provides the ability to enforce
stringent password strength requirements. It is provided
in an RPM of the same name.
The man pages pam_cracklib(8) and pam_passwdqc(8)
provide information on the capabilities and configuration of
each. |
contains 6 rules |
Set Password Quality Requirements, if using
pam_cracklibgroupThe pam_cracklib PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_cracklib to require at least one uppercase
character, lowercase character, digit, and other (special)
character, locate the following line in /etc/pam.d/system-auth:
password requisite pam_cracklib.so try_first_pass retry=3
and then alter it to read:
password required pam_cracklib.so try_first_pass retry=3 maxrepeat=3 minlen=14 dcredit=-1 ucredit=-1 ocredit=-1 lcredit=-1 difok=4
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth.
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows.
|
contains 6 rules |
Set Password Retry Prompts Permitted Per-SessionruleTo configure the number of retry prompts that are permitted per-session:
Edit the pam_cracklib.so statement in /etc/pam.d/system-auth to
show retry=3, or a lower value if site policy is more restrictive.
The DoD requirement is a maximum of 3 prompts per session.
identifiers:
CCE-27123-9 references:
IA-5(c), 1092, Test attestation on 20121024 by DS |
Set Password Strength Minimum Digit CharactersruleThe pam_cracklib module's dcredit parameter controls requirements for
usage of digits in a password. When set to a negative number, any password will be required to
contain that many digits. When set to a positive number, pam_cracklib will grant +1 additional
length credit for each digit.
Add dcredit=-1 after pam_cracklib.so to require use of a digit in passwords.
identifiers:
CCE-26374-9, DISA FSO RHEL-06-000056 references:
IA-5(b), IA-5(c), 194, 194, Test attestation on 20121024 by DS Remediation script:var_password_pam_dcredit="-1"
if grep -q "dcredit=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(dcredit *= *\).*/\1$var_password_pam_dcredit/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/pam_cracklib.so/ s/$/ dcredit=$var_password_pam_dcredit/" /etc/pam.d/system-auth
fi
|
Set Password Strength Minimum Uppercase CharactersruleThe pam_cracklib module's ucredit= parameter controls requirements for
usage of uppercase letters in a password. When set to a negative number, any password will be required to
contain that many uppercase characters. When set to a positive number, pam_cracklib will grant +1 additional
length credit for each uppercase character.
Add ucredit=-1 after pam_cracklib.so to require use of an upper case character in passwords.
identifiers:
CCE-26601-5, DISA FSO RHEL-06-000057 references:
IA-5(b), IA-5(c), IA-5(1)(a), 192, Test attestation on 20121024 by DS Remediation script:var_password_pam_ucredit="-1"
if grep -q "ucredit=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(ucredit *= *\).*/\1$var_password_pam_ucredit/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/pam_cracklib.so/ s/$/ ucredit=$var_password_pam_ucredit/" /etc/pam.d/system-auth
fi
|
Set Password Strength Minimum Special CharactersruleThe pam_cracklib module's ocredit= parameter controls requirements for
usage of special (or ``other'') characters in a password. When set to a negative number, any password will be required to
contain that many special characters. When set to a positive number, pam_cracklib will grant +1 additional
length credit for each special character.
Add ocredit=-1 after pam_cracklib.so to require use of a special character in passwords.
identifiers:
CCE-26409-3, DISA FSO RHEL-06-000058 references:
IA-5(b), IA-5(c), IA-5(1)(a), 1619, 266, Test attestation on 20121024 by DS Remediation script:var_password_pam_ocredit="-1"
if grep -q "ocredit=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(ocredit *= *\).*/\1$var_password_pam_ocredit/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/pam_cracklib.so/ s/$/ ocredit=$var_password_pam_ocredit/" /etc/pam.d/system-auth
fi
|
Set Password Strength Minimum Lowercase CharactersruleThe pam_cracklib module's lcredit= parameter controls requirements for
usage of lowercase letters in a password. When set to a negative number, any password will be required to
contain that many lowercase characters. When set to a positive number, pam_cracklib will grant +1 additional
length credit for each lowercase character.
Add lcredit=-1 after pam_cracklib.so to require use of a lowercase character in passwords.
identifiers:
CCE-26631-2, DISA FSO RHEL-06-000059 references:
IA-5(b), IA-5(c), IA-5(1)(a), 193, Test attestation on 20121024 by DS Remediation script:var_password_pam_lcredit="-1"
if grep -q "lcredit=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(lcredit *= *\).*/\1$var_password_pam_lcredit/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/pam_cracklib.so/ s/$/ lcredit=$var_password_pam_lcredit/" /etc/pam.d/system-auth
fi
|
Set Password Strength Minimum Different CharactersruleThe pam_cracklib module's difok parameter controls requirements for
usage of different characters during a password change.
Add difok=4 after pam_cracklib.so to require differing
characters when changing passwords. The DoD requirement is 4.
identifiers:
CCE-26615-5, DISA FSO RHEL-06-000060 references:
IA-5(b), IA-5(c), IA-5(1)(b), 195, Test attestation on 20121024 by DS Remediation script:var_password_pam_difok="4"
if grep -q "difok=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(difok *= *\).*/\1$var_password_pam_difok/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/pam_cracklib.so/ s/$/ difok=$var_password_pam_difok/" /etc/pam.d/system-auth
fi
|
Set Lockouts for Failed Password AttemptsgroupThe pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock.
|
contains 2 rules |
Set Deny For Failed Password Attemptsrule
To configure the system to lock out accounts after a number of incorrect login
attempts using pam_faillock.so, modify the content of both
/etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:
Add the following line immediately before the pam_unix.so statement in the AUTH section:
auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately after the pam_unix.so statement in the AUTH section:
auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately before the pam_unix.so statement in the ACCOUNT section:
account required pam_faillock.so
identifiers:
CCE-26844-1, DISA FSO RHEL-06-000061 references:
AC-7(a), 44 Remediation script:var_accounts_passwords_pam_faillock_deny="3"
AUTH_FILES[0]="/etc/pam.d/system-auth"
AUTH_FILES[1]="/etc/pam.d/password-auth"
for pamFile in "${AUTH_FILES[@]}"
do
# pam_faillock.so already present?
if grep -q "^auth.*pam_faillock.so.*" $pamFile; then
# pam_faillock.so present, deny directive present?
if grep -q "^auth.*[default=die].*pam_faillock.so.*authfail.*deny=" $pamFile; then
# both pam_faillock.so & deny present, just correct deny directive value
sed -i --follow-symlink "s/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\(deny *= *\).*/\1\2$var_accounts_passwords_pam_faillock_deny/" $pamFile
sed -i --follow-symlink "s/\(^auth.*[default=die].*pam_faillock.so.*authfail.*\)\(deny *= *\).*/\1\2$var_accounts_passwords_pam_faillock_deny/" $pamFile
# pam_faillock.so present, but deny directive not yet
else
# append correct deny value to appropriate places
sed -i --follow-symlink "/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ deny=$var_accounts_passwords_pam_faillock_deny/" $pamFile
sed -i --follow-symlink "/^auth.*[default=die].*pam_faillock.so.*authfail.*/ s/$/ deny=$var_accounts_passwords_pam_faillock_deny/" $pamFile
fi
# pam_faillock.so not present yet
else
# insert pam_faillock.so preauth & authfail rows with proper value of the 'deny' option
sed -i --follow-symlink "/^auth.*sufficient.*pam_unix.so.*/i auth required pam_faillock.so preauth silent deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
sed -i --follow-symlink "/^auth.*sufficient.*pam_unix.so.*/a auth [default=die] pam_faillock.so authfail deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
sed -i --follow-symlink "/^account.*required.*pam_unix.so/i account required pam_faillock.so" $pamFile
fi
done
|
Limit Password ReuseruleDo not allow users to reuse recent passwords. This can
be accomplished by using the remember option for the pam_unix PAM
module. In the file /etc/pam.d/system-auth, append remember=10 to the
line which refers to the pam_unix.so module, as shown:
password sufficient pam_unix.so existing_options remember=10
The DoD STIG requirement is 5 passwords. identifiers:
CCE-26741-9, DISA FSO RHEL-06-000274 references:
IA-5(f), IA-5(1)(e), 200, Test attestation on 20121024 by DS Remediation script:var_password_pam_unix_remember="10"
if grep -q "remember=" /etc/pam.d/system-auth; then
sed -i --follow-symlink "s/\(remember *= *\).*/\1$var_password_pam_unix_remember/" /etc/pam.d/system-auth
else
sed -i --follow-symlink "/^password[[:space:]]\+sufficient[[:space:]]\+pam_unix.so/ s/$/ remember=$var_password_pam_unix_remember/" /etc/pam.d/system-auth
fi
|
Set Password Hashing AlgorithmgroupThe system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
contains 3 rules |
Set Password Hashing Algorithm in /etc/pam.d/system-authrule
In /etc/pam.d/system-auth, the password section of
the file controls which PAM modules execute during a password change.
Set the pam_unix.so module in the
password section to include the argument sha512, as shown below:
password sufficient pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for the new
passwords will be generated using the SHA-512 algorithm.
This is the default.
identifiers:
CCE-26303-8, DISA FSO RHEL-06-000062 references:
IA-5(b), IA-5(c), IA-5(1)(c), IA-7, 803, Test attestation on 20121024 by DS Remediation script:if ! grep -q "^password.*sufficient.*pam_unix.so.*sha512" /etc/pam.d/system-auth; then
sed -i --follow-symlink "/^password.*sufficient.*pam_unix.so/ s/$/ sha512/" /etc/pam.d/system-auth
fi
|
Set Password Hashing Algorithm in /etc/login.defsrule
In /etc/login.defs, add or correct the following line to ensure
the system will use SHA-512 as the hashing algorithm:
ENCRYPT_METHOD SHA512
identifiers:
CCE-27228-6, DISA FSO RHEL-06-000063 references:
IA-5(b), IA-5(c), IA-5(1)(c), IA-7, 803, Test attestation on 20121024 by DS Remediation script:if grep --silent ^ENCRYPT_METHOD /etc/login.defs ; then
sed -i 's/^ENCRYPT_METHOD.*/ENCRYPT_METHOD SHA512/g' /etc/login.defs
else
echo "" >> /etc/login.defs
echo "ENCRYPT_METHOD SHA512" >> /etc/login.defs
fi
|
Set Password Hashing Algorithm in /etc/libuser.confrule
In /etc/libuser.conf, add or correct the following line in its
[defaults] section to ensure the system will use the SHA-512
algorithm for password hashing:
crypt_style = sha512
identifiers:
CCE-27229-4, DISA FSO RHEL-06-000064 references:
IA-5(b), IA-5(c), IA-5(1)(c), IA-7, 803, Test attestation on 20121026 by DS |
Secure Session Configuration Files for Login AccountsgroupWhen a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
contains 7 rules |
Ensure that No Dangerous Directories Exist in Root's PathgroupThe active path of the root account can be obtained by
starting a new root shell and running:
$ sudo echo $PATH
This will produce a colon-separated list of
directories in the path.
Certain path elements could be considered dangerous, as they could lead
to root executing unknown or
untrusted programs, which could contain malicious
code.
Since root may sometimes work inside
untrusted directories, the . character, which represents the
current directory, should never be in the root path, nor should any
directory which can be written to by an unprivileged or
semi-privileged (system) user.
It is a good practice for administrators to always execute
privileged commands by typing the full path to the
command. |
contains 1 rule |
Ensure that Root's Path Does Not Include World or Group-Writable Directoriesrule
For each element in root's path, run:
$ sudo ls -ld DIR
and ensure that write permissions are disabled for group and
other.
identifiers:
CCE-26768-2 references:
CM-6(b), 366 |
Ensure that Users Have Sensible Umask Valuesgroup
The umask setting controls the default permissions
for the creation of new files.
With a default umask setting of 077, files and directories
created by users will not be readable by any other user on the
system. Users who wish to make specific files group- or
world-readable can accomplish this by using the chmod command.
Additionally, users can make all their files readable to their
group by default by setting a umask of 027 in their shell
configuration files. If default per-user groups exist (that is, if
every user has a default group whose name is the same as that
user's username and whose only member is the user), then it may
even be safe for users to select a umask of 007, making it very
easy to intentionally share files with groups of which the user is
a member.
|
contains 4 rules |
Ensure the Default Bash Umask is Set Correctlyrule
To ensure the default umask for users of the Bash shell is set properly,
add or correct the umask setting in /etc/bashrc to read
as follows:
umask 077
identifiers:
CCE-26917-5, DISA FSO RHEL-06-000342 references:
SA-8, 366, Test attestation on 20140912 by JL Remediation script:var_accounts_user_umask="077"
grep -q umask /etc/bashrc && \
sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/bashrc
if ! [ $? -eq 0 ]; then
echo "umask $var_accounts_user_umask" >> /etc/bashrc
fi
|
Ensure the Default C Shell Umask is Set Correctlyrule
To ensure the default umask for users of the C shell is set properly,
add or correct the umask setting in /etc/csh.cshrc to read as follows:
umask 077
identifiers:
CCE-27034-8, DISA FSO RHEL-06-000343 references:
SA-8, 366, Test attestation on 20140912 by JL Remediation script:var_accounts_user_umask="077"
grep -q umask /etc/csh.cshrc && \
sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/csh.cshrc
if ! [ $? -eq 0 ]; then
echo "umask $var_accounts_user_umask" >> /etc/csh.cshrc
fi
|
Ensure the Default Umask is Set Correctly in /etc/profilerule
To ensure the default umask controlled by /etc/profile is set properly,
add or correct the umask setting in /etc/profile to read as follows:
umask 077
identifiers:
CCE-26669-2, DISA FSO RHEL-06-000344 references:
SA-8, 366, Test attestation on 20120929 by swells Remediation script:var_accounts_user_umask="077"
grep -q umask /etc/profile && \
sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/profile
if ! [ $? -eq 0 ]; then
echo "umask $var_accounts_user_umask" >> /etc/profile
fi
|
Ensure the Default Umask is Set Correctly in login.defsrule
To ensure the default umask controlled by /etc/login.defs is set properly,
add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK 077
identifiers:
CCE-26371-5, DISA FSO RHEL-06-000345 references:
SA-8, 366, Test attestation on 20140912 by JL Remediation script:var_accounts_user_umask="077"
grep -q UMASK /etc/login.defs && \
sed -i "s/UMASK.*/UMASK $var_accounts_user_umask/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "UMASK $var_accounts_user_umask" >> /etc/login.defs
fi
|
Limit the Number of Concurrent Login Sessions Allowed Per Userrule
Limiting the number of allowed users and sessions per user can limit risks related to Denial of
Service attacks. This addresses concurrent sessions for a single account and does not address
concurrent sessions by a single user via multiple accounts. The DoD requirement is 10. To set the number of concurrent
sessions per user add the following line in /etc/security/limits.conf:
* hard maxlogins 3
identifiers:
CCE-27457-1, DISA FSO RHEL-06-000319 references:
AC-10, 54 Remediation script:var_accounts_max_concurrent_login_sessions="3"
echo "* hard maxlogins $var_accounts_max_concurrent_login_sessions" >> /etc/security/limits.conf
|
Ensure that User Home Directories are not Group-Writable or World-ReadableruleFor each human user of the system, view the
permissions of the user's home directory:
$ sudo ls -ld /home/USER
Ensure that the directory is not group-writable and that it
is not world-readable. If necessary, repair the permissions:
$ sudo chmod g-w /home/USER
$ sudo chmod o-rwx /home/USER
identifiers:
CCE-26981-1 references:
AC-6(7) |
Protect Physical Console AccessgroupIt is impossible to fully protect a system from an
attacker with physical access, so securing the space in which the
system is located should be considered a necessary step. However,
there are some steps which, if taken, make it more difficult for an
attacker to quickly or undetectably modify a system from its
console. |
contains 11 rules |
Set Boot Loader PasswordgroupDuring the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default Red Hat Enterprise Linux boot loader for x86 systems is called GRUB.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly.
|
contains 4 rules |
Verify /etc/grub.conf User OwnershipruleThe file /etc/grub.conf should
be owned by the root user to prevent destruction
or modification of the file.
To properly set the owner of /etc/grub.conf, run the command:
$ sudo chown root /etc/grub.conf
identifiers:
CCE-26995-1, DISA FSO RHEL-06-000065 references:
AC-6(7), 225, Test attestation on 20121026 by DS Remediation script:chown root /etc/grub.conf
|
Verify /etc/grub.conf Group OwnershipruleThe file /etc/grub.conf should
be group-owned by the root group to prevent
destruction or modification of the file.
To properly set the group owner of /etc/grub.conf, run the command:
$ sudo chgrp root /etc/grub.conf
identifiers:
CCE-27022-3, DISA FSO RHEL-06-000066 references:
AC-6(7), 225, Test attestation on 20121026 by DS Remediation script:chgrp root /etc/grub.conf
|
Verify /boot/grub/grub.conf PermissionsruleFile permissions for /boot/grub/grub.conf should be set to 600, which
is the default.
To properly set the permissions of /boot/grub/grub.conf, run the command:
$ sudo chmod 600 /boot/grub/grub.conf
identifiers:
CCE-26949-8, DISA FSO RHEL-06-000067 references:
AC-6(7), 225, Test attestation on 20121026 by DS Remediation script:chmod 600 /boot/grub/grub.conf
|
Set Boot Loader PasswordruleThe grub boot loader should have password protection
enabled to protect boot-time settings.
To do so, select a password and then generate a hash from it by running the following command:
$ grub-crypt --sha-512
When prompted to enter a password, insert the following line into /etc/grub.conf
immediately after the header comments. (Use the output from grub-crypt as the
value of password-hash):
password --encrypted password-hash
NOTE: To meet FISMA Moderate, the bootloader password MUST differ from the root password.
identifiers:
CCE-26911-8, DISA FSO RHEL-06-000068 references:
IA-2(1), IA-5(e) AC-3, 213, Test attestation on 20121026 by DS |
Configure Screen LockinggroupWhen a user must temporarily leave an account
logged-in, screen locking should be employed to prevent passersby
from abusing the account. User education and training is
particularly important for screen locking to be effective, and policies
can be implemented to reinforce this.
Automatic screen locking is only meant as a safeguard for
those cases where a user forgot to lock the screen. |
contains 4 rules |
Configure GUI Screen LockinggroupIn the default GNOME desktop, the screen can be locked
by choosing Lock Screen from the System menu.
The gconftool-2 program can be used to enforce mandatory
screen locking settings for the default GNOME environment.
The
following sections detail commands to enforce idle activation of the screensaver,
screen locking, a blank-screen screensaver, and an idle
activation time.
Because users should be trained to lock the screen when they
step away from the computer, the automatic locking feature is only
meant as a backup. The Lock Screen icon from the System menu can
also be dragged to the taskbar in order to facilitate even more
convenient screen-locking.
The root account cannot be screen-locked, but this should
have no practical effect as the root account should never be used
to log into an X Windows environment, and should only be used to
for direct login via console in emergency circumstances.
For more information about configuring GNOME screensaver, see
http://live.gnome.org/GnomeScreensaver. For more information about
enforcing preferences in the GNOME environment using the GConf
configuration system, see http://projects.gnome.org/gconf and
the man page gconftool-2(1). |
contains 3 rules |
Set GNOME Login Inactivity Timeoutrule
Run the following command to set the idle time-out value for
inactivity in the GNOME desktop to 15 minutes:
$ sudo gconftool-2 \
--direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type int \
--set /desktop/gnome/session/idle_delay 15
identifiers:
CCE-26828-4, DISA FSO RHEL-06-000257 references:
AC-11(a), 57 Remediation script:inactivity_timeout_value="15"
# Install GConf2 package if not installed
if ! rpm -q GConf2; then
yum -y install GConf2
fi
# Set the idle time-out value for inactivity in the GNOME desktop to meet the
# requirement
gconftool-2 --direct \
--config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
--type int \
--set /desktop/gnome/session/idle_delay ${inactivity_timeout_value}
|
GNOME Desktop Screensaver Mandatory Userule
Run the following command to activate the screensaver
in the GNOME desktop after a period of inactivity:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/gnome-screensaver/idle_activation_enabled true
identifiers:
CCE-26600-7, DISA FSO RHEL-06-000258 references:
AC-11(a), 57 Remediation script:# Install GConf2 package if not installed
if ! rpm -q GConf2; then
yum -y install GConf2
fi
# Set the screensaver activation in the GNOME desktop after a period of inactivity
gconftool-2 --direct \
--config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
--type bool \
--set /apps/gnome-screensaver/idle_activation_enabled true
|
Enable Screen Lock Activation After Idle Periodrule
Run the following command to activate locking of the screensaver
in the GNOME desktop when it is activated:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/gnome-screensaver/lock_enabled true
identifiers:
CCE-26235-2, DISA FSO RHEL-06-000259 references:
AC-11(a), 57 Remediation script:# Install GConf2 package if not installed
if ! rpm -q GConf2; then
yum -y install GConf2
fi
# Set the screensaver locking activation in the GNOME desktop when the
# screensaver is activated
gconftool-2 --direct \
--config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
--type bool \
--set /apps/gnome-screensaver/lock_enabled true
|
Configure Console Screen Lockinggroup
A console screen locking mechanism is provided in the
screen package, which is not installed by default.
|
contains 1 rule |
Install the screen Packagerule
To enable console screen locking, install the screen package:
$ sudo yum install screen
Instruct users to begin new terminal sessions with the following command:
$ screen
The console can now be locked with the following key combination:
ctrl+a x
identifiers:
CCE-26940-7, DISA FSO RHEL-06-000071 references:
58, Test attestation on 20121026 by DS Remediation script:yum -y install screen
|
Require Authentication for Single User ModeruleSingle-user mode is intended as a system recovery
method, providing a single user root access to the system by
providing a boot option at startup. By default, no authentication
is performed if single-user mode is selected.
To require entry of the root password even if the system is
started in single-user mode, add or correct the following line in the
file /etc/sysconfig/init:
SINGLE=/sbin/sulogin
identifiers:
CCE-27040-5, DISA FSO RHEL-06-000069 references:
IA-2(1), AC-3, 213, Test attestation on 20121024 by DS Remediation script:grep -q ^SINGLE /etc/sysconfig/init && \
sed -i "s/SINGLE.*/SINGLE=\/sbin\/sulogin/g" /etc/sysconfig/init
if ! [ $? -eq 0 ]; then
echo "SINGLE=/sbin/sulogin" >> /etc/sysconfig/init
fi
|
Disable Ctrl-Alt-Del Reboot Activationrule
By default, the system includes the following line in
/etc/init/control-alt-delete.conf
to reboot the system when the Ctrl-Alt-Del key sequence is pressed:
exec /sbin/shutdown -r now "Control-Alt-Delete pressed"
To configure the system to log a message instead of
rebooting the system, alter that line to read as follows:
exec /usr/bin/logger -p security.info "Control-Alt-Delete pressed"
identifiers:
CCE-27567-7, DISA FSO RHEL-06-000286 Remediation script:# If system does not contain control-alt-delete.override,
if [ ! -f /etc/init/control-alt-delete.override ]; then
# but does have control-alt-delete.conf file,
if [ -f /etc/init/control-alt-delete.conf ]; then
# then copy .conf to .override to maintain persistency
cp /etc/init/control-alt-delete.conf /etc/init/control-alt-delete.override
fi
fi
sed -i 's,^exec.*$,exec /usr/bin/logger -p authpriv.notice -t init "Ctrl-Alt-Del was pressed and ignored",' /etc/init/control-alt-delete.override
|
Disable Interactive Bootrule
To disable the ability for users to perform interactive startups,
edit the file /etc/sysconfig/init.
Add or correct the line:
PROMPT=no
The PROMPT option allows the console user to perform an
interactive system startup, in which it is possible to select the
set of services which are started on boot.
identifiers:
CCE-27043-9, DISA FSO RHEL-06-000070 references:
SC-2, AC-3, 213, Test attestation on 20121024 by DS Remediation script:grep -q ^PROMPT /etc/sysconfig/init && \
sed -i "s/PROMPT.*/PROMPT=no/g" /etc/sysconfig/init
if ! [ $? -eq 0 ]; then
echo "PROMPT=no" >> /etc/sysconfig/init
fi
|
Warning Banners for System AccessesgroupEach system should expose as little information about
itself as possible.
System banners, which are typically displayed just before a
login prompt, give out information about the service or the host's
operating system. This might include the distribution name and the
system kernel version, and the particular version of a network
service. This information can assist intruders in gaining access to
the system as it can reveal whether the system is running
vulnerable software. Most network services can be configured to
limit what information is displayed.
Many organizations implement security policies that require a
system banner provide notice of the system's ownership, provide
warning to unauthorized users, and remind authorized users of their
consent to monitoring. |
contains 3 rules |
Implement a GUI Warning BannergroupIn the default graphical environment, users logging
directly into the system are greeted with a login screen provided
by the GNOME Display Manager (GDM). The warning banner should be
displayed in this graphical environment for these users.
The following sections describe how to configure the GDM login
banner.
|
contains 2 rules |
Enable GUI Warning Bannerrule
To enable displaying a login warning banner in the GNOME
Display Manager's login screen, run the following command:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/gdm/simple-greeter/banner_message_enable true
To display a banner, this setting must be enabled and then
banner text must also be set.
identifiers:
CCE-27195-7, DISA FSO RHEL-06-000324 references:
AC-8(a), AC-8(b), AC-8(c), 48, 50 Remediation script:# Install GConf2 package if not installed
if ! rpm -q GConf2; then
yum -y install GConf2
fi
# Enable displaying of a login warning banner in the GNOME Display Manager's
# login screen
gconftool-2 --direct \
--config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
--type bool \
--set /apps/gdm/simple-greeter/banner_message_enable true
|
Set GUI Warning Banner Textrule
To set the text shown by the GNOME Display Manager
in the login screen, run the following command:
$ sudo gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type string \
--set /apps/gdm/simple-greeter/banner_message_text \
"Text of the warning banner here"
When entering a warning banner that spans several lines, remember
to begin and end the string with ". This command writes
directly either to the /etc/gconf/gconf.xml.mandatory/%gconf-tree.xml
if it exists or to the file /etc/gconf/gconf.xml.mandatory/apps/gdm/simple-greeter/%gconf.xml.
Either of these files can later be edited directly if necessary.
identifiers:
CCE-27017-3, DISA FSO RHEL-06-000326 references:
AC-8(a), AC-8(b), AC-8(c), 48, 1384, 1385, 1386, 1387, 1388 Remediation script:login_banner_text="You[\s\n]+are[\s\n]+accessing[\s\n]+a[\s\n]+U.S.[\s\n]+Government[\s\n]+\(USG\)[\s\n]+Information[\s\n]+System[\s\n]+\(IS\)[\s\n]+that[\s\n]+is[\s\n]+provided[\s\n]+for[\s\n]+USG-authorized[\s\n]+use[\s\n]+only.[\s\n]*By[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+\(which[\s\n]+includes[\s\n]+any[\s\n]+device[\s\n]+attached[\s\n]+to[\s\n]+this[\s\n]+IS\),[\s\n]+you[\s\n]+consent[\s\n]+to[\s\n]+the[\s\n]+following[\s\n]+conditions\:[\s\n]*-[\s\n]*The[\s\n]+USG[\s\n]+routinely[\s\n]+intercepts[\s\n]+and[\s\n]+monitors[\s\n]+communications[\s\n]+on[\s\n]+this[\s\n]+IS[\s\n]+for[\s\n]+purposes[\s\n]+including,[\s\n]+but[\s\n]+not[\s\n]+limited[\s\n]+to,[\s\n]+penetration[\s\n]+testing,[\s\n]+COMSEC[\s\n]+monitoring,[\s\n]+network[\s\n]+operations[\s\n]+and[\s\n]+defense,[\s\n]+personnel[\s\n]+misconduct[\s\n]+\(PM\),[\s\n]+law[\s\n]+enforcement[\s\n]+\(LE\),[\s\n]+and[\s\n]+counterintelligence[\s\n]+\(CI\)[\s\n]+investigations.[\s\n]*-[\s\n]*At[\s\n]+any[\s\n]+time,[\s\n]+the[\s\n]+USG[\s\n]+may[\s\n]+inspect[\s\n]+and[\s\n]+seize[\s\n]+data[\s\n]+stored[\s\n]+on[\s\n]+this[\s\n]+IS.[\s\n]*-[\s\n]*Communications[\s\n]+using,[\s\n]+or[\s\n]+data[\s\n]+stored[\s\n]+on,[\s\n]+this[\s\n]+IS[\s\n]+are[\s\n]+not[\s\n]+private,[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+routine[\s\n]+monitoring,[\s\n]+interception,[\s\n]+and[\s\n]+search,[\s\n]+and[\s\n]+may[\s\n]+be[\s\n]+disclosed[\s\n]+or[\s\n]+used[\s\n]+for[\s\n]+any[\s\n]+USG-authorized[\s\n]+purpose.[\s\n]*-[\s\n]*This[\s\n]+IS[\s\n]+includes[\s\n]+security[\s\n]+measures[\s\n]+\(e.g.,[\s\n]+authentication[\s\n]+and[\s\n]+access[\s\n]+controls\)[\s\n]+to[\s\n]+protect[\s\n]+USG[\s\n]+interests[\s\n]+--[\s\n]+not[\s\n]+for[\s\n]+your[\s\n]+personal[\s\n]+benefit[\s\n]+or[\s\n]+privacy.[\s\n]*-[\s\n]*Notwithstanding[\s\n]+the[\s\n]+above,[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+does[\s\n]+not[\s\n]+constitute[\s\n]+consent[\s\n]+to[\s\n]+PM,[\s\n]+LE[\s\n]+or[\s\n]+CI[\s\n]+investigative[\s\n]+searching[\s\n]+or[\s\n]+monitoring[\s\n]+of[\s\n]+the[\s\n]+content[\s\n]+of[\s\n]+privileged[\s\n]+communications,[\s\n]+or[\s\n]+work[\s\n]+product,[\s\n]+related[\s\n]+to[\s\n]+personal[\s\n]+representation[\s\n]+or[\s\n]+services[\s\n]+by[\s\n]+attorneys,[\s\n]+psychotherapists,[\s\n]+or[\s\n]+clergy,[\s\n]+and[\s\n]+their[\s\n]+assistants.[\s\n]+Such[\s\n]+communications[\s\n]+and[\s\n]+work[\s\n]+product[\s\n]+are[\s\n]+private[\s\n]+and[\s\n]+confidential.[\s\n]+See[\s\n]+User[\s\n]+Agreement[\s\n]+for[\s\n]+details."
# Install GConf2 package if not installed
if ! rpm -q GConf2; then
yum -y install GConf2
fi
# Expand the login_banner_text value - there was a regular-expression
# matching various banners, needs to be expanded
banner_expanded=$(echo "$login_banner_text" | sed 's/\[\\s\\n\][*+]/ /g;s/\\//g;')
# Set the text shown by the GNOME Display Manager in the login screen
gconftool-2 --direct \
--config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
--type string \
--set /apps/gdm/simple-greeter/banner_message_text "${banner_expanded}"
|
Modify the System Login Bannerrule
To configure the system login banner:
Edit /etc/issue. Replace the default text with a message
compliant with the local site policy or a legal disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that is
provided for USG-authorized use only. By using this IS (which includes any
device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes
including, but not limited to, penetration testing, COMSEC monitoring, network
operations and defense, personnel misconduct (PM), law enforcement (LE), and
counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject
to routine monitoring, interception, and search, and may be disclosed or used
for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls)
to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative
searching or monitoring of the content of privileged communications, or work
product, related to personal representation or services by attorneys,
psychotherapists, or clergy, and their assistants. Such communications and work
product are private and confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't.
identifiers:
CCE-26974-6, DISA FSO RHEL-06-000073 references:
AC-8(a), AC-8(b), AC-8(c), 48, 1384, 1385, 1386, 1387, 1388, Test attestation on 20121026 by DS Remediation script:login_banner_text="You[\s\n]+are[\s\n]+accessing[\s\n]+a[\s\n]+U.S.[\s\n]+Government[\s\n]+\(USG\)[\s\n]+Information[\s\n]+System[\s\n]+\(IS\)[\s\n]+that[\s\n]+is[\s\n]+provided[\s\n]+for[\s\n]+USG-authorized[\s\n]+use[\s\n]+only.[\s\n]*By[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+\(which[\s\n]+includes[\s\n]+any[\s\n]+device[\s\n]+attached[\s\n]+to[\s\n]+this[\s\n]+IS\),[\s\n]+you[\s\n]+consent[\s\n]+to[\s\n]+the[\s\n]+following[\s\n]+conditions\:[\s\n]*-[\s\n]*The[\s\n]+USG[\s\n]+routinely[\s\n]+intercepts[\s\n]+and[\s\n]+monitors[\s\n]+communications[\s\n]+on[\s\n]+this[\s\n]+IS[\s\n]+for[\s\n]+purposes[\s\n]+including,[\s\n]+but[\s\n]+not[\s\n]+limited[\s\n]+to,[\s\n]+penetration[\s\n]+testing,[\s\n]+COMSEC[\s\n]+monitoring,[\s\n]+network[\s\n]+operations[\s\n]+and[\s\n]+defense,[\s\n]+personnel[\s\n]+misconduct[\s\n]+\(PM\),[\s\n]+law[\s\n]+enforcement[\s\n]+\(LE\),[\s\n]+and[\s\n]+counterintelligence[\s\n]+\(CI\)[\s\n]+investigations.[\s\n]*-[\s\n]*At[\s\n]+any[\s\n]+time,[\s\n]+the[\s\n]+USG[\s\n]+may[\s\n]+inspect[\s\n]+and[\s\n]+seize[\s\n]+data[\s\n]+stored[\s\n]+on[\s\n]+this[\s\n]+IS.[\s\n]*-[\s\n]*Communications[\s\n]+using,[\s\n]+or[\s\n]+data[\s\n]+stored[\s\n]+on,[\s\n]+this[\s\n]+IS[\s\n]+are[\s\n]+not[\s\n]+private,[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+routine[\s\n]+monitoring,[\s\n]+interception,[\s\n]+and[\s\n]+search,[\s\n]+and[\s\n]+may[\s\n]+be[\s\n]+disclosed[\s\n]+or[\s\n]+used[\s\n]+for[\s\n]+any[\s\n]+USG-authorized[\s\n]+purpose.[\s\n]*-[\s\n]*This[\s\n]+IS[\s\n]+includes[\s\n]+security[\s\n]+measures[\s\n]+\(e.g.,[\s\n]+authentication[\s\n]+and[\s\n]+access[\s\n]+controls\)[\s\n]+to[\s\n]+protect[\s\n]+USG[\s\n]+interests[\s\n]+--[\s\n]+not[\s\n]+for[\s\n]+your[\s\n]+personal[\s\n]+benefit[\s\n]+or[\s\n]+privacy.[\s\n]*-[\s\n]*Notwithstanding[\s\n]+the[\s\n]+above,[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+does[\s\n]+not[\s\n]+constitute[\s\n]+consent[\s\n]+to[\s\n]+PM,[\s\n]+LE[\s\n]+or[\s\n]+CI[\s\n]+investigative[\s\n]+searching[\s\n]+or[\s\n]+monitoring[\s\n]+of[\s\n]+the[\s\n]+content[\s\n]+of[\s\n]+privileged[\s\n]+communications,[\s\n]+or[\s\n]+work[\s\n]+product,[\s\n]+related[\s\n]+to[\s\n]+personal[\s\n]+representation[\s\n]+or[\s\n]+services[\s\n]+by[\s\n]+attorneys,[\s\n]+psychotherapists,[\s\n]+or[\s\n]+clergy,[\s\n]+and[\s\n]+their[\s\n]+assistants.[\s\n]+Such[\s\n]+communications[\s\n]+and[\s\n]+work[\s\n]+product[\s\n]+are[\s\n]+private[\s\n]+and[\s\n]+confidential.[\s\n]+See[\s\n]+User[\s\n]+Agreement[\s\n]+for[\s\n]+details."
# There was a regular-expression matching various banners, needs to be expanded
expanded=$(echo "$login_banner_text" | sed 's/\[\\s\\n\][+*]/ /g;s/\\//g;s/[^-]- /\n\n-/g')
formatted=$(echo "$expanded" | fold -sw 80)
cat <<EOF >/etc/issue
$formatted
EOF
printf "\n" >> /etc/issue
|
Network Configuration and FirewallsgroupMost machines must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
contains 34 rules |
Kernel Parameters Which Affect NetworkinggroupThe sysctl utility is used to set
parameters which affect the operation of the Linux kernel. Kernel parameters
which affect networking and have security implications are described here.
|
contains 15 rules |
Network Parameters for Hosts OnlygroupIf the system is not going to be used as a router, then setting certain
kernel parameters ensure that the host will not perform routing
of network traffic. |
contains 3 rules |
Disable Kernel Parameter for Sending ICMP Redirects by Defaultrule
To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.send_redirects = 0
identifiers:
CCE-27001-7, DISA FSO RHEL-06-000080 references:
AC-4, CM-7, SC-5, SC-7, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.default.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects=0
#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.send_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.default.send_redirects.*/net.ipv4.conf.default.send_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.default.send_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.default.send_redirects = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Sending ICMP Redirects for All Interfacesrule
To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.send_redirects = 0
identifiers:
CCE-27004-1, DISA FSO RHEL-06-000081 references:
CM-7, SC-5(1), 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects=0
#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.send_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.send_redirects.*/net.ipv4.conf.all.send_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.send_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.send_redirects = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for IP Forwardingrule
To set the runtime status of the net.ipv4.ip_forward kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.ip_forward=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.ip_forward = 0
identifiers:
CCE-26866-4, DISA FSO RHEL-06-000082 references:
CM-7, SC-5, 366, Test attestation on 20121024 by DS |
Network Related Kernel Runtime Parameters for Hosts and RoutersgroupCertain kernel parameters should be set for systems which are
acting as either hosts or routers to improve the system's ability defend
against certain types of IPv4 protocol attacks. |
contains 12 rules |
Disable Kernel Parameter for Accepting Source-Routed Packets for All Interfacesrule
To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.accept_source_route = 0
identifiers:
CCE-27037-1, DISA FSO RHEL-06-000083 references:
CM-7, SC-5, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route=0
#
# If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.accept_source_route = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.accept_source_route /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.accept_source_route.*/net.ipv4.conf.all.accept_source_route = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.accept_source_route to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.accept_source_route = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Accepting ICMP Redirects for All Interfacesrule
To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.accept_redirects = 0
identifiers:
CCE-27027-2, DISA FSO RHEL-06-000084 references:
CM-7, SC-5, 1503, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects=0
#
# If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.accept_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.accept_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.accept_redirects.*/net.ipv4.conf.all.accept_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.accept_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.accept_redirects = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Accepting Secure Redirects for All Interfacesrule
To set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.secure_redirects = 0
identifiers:
CCE-26854-0, DISA FSO RHEL-06-000086 references:
AC-4, CM-7, SC-5, 1503, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects=0
#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.secure_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.secure_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.secure_redirects.*/net.ipv4.conf.all.secure_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.secure_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.secure_redirects = 0" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Log Martian Packetsrule
To set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.log_martians=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.log_martians = 1
identifiers:
CCE-27066-0, DISA FSO RHEL-06-000088 references:
AC-3(10), CM-7, SC-5(3), 126, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.log_martians
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.log_martians=1
#
# If net.ipv4.conf.all.log_martians present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.conf.all.log_martians = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.log_martians /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.log_martians.*/net.ipv4.conf.all.log_martians = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.log_martians to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.log_martians = 1" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Accepting Source-Routed Packets By Defaultrule
To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.accept_source_route = 0
identifiers:
CCE-26983-7, DISA FSO RHEL-06-000089 references:
AC-4, CM-7, SC-5, SC-7, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route=0
#
# If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.accept_source_route = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.accept_source_route /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.default.accept_source_route.*/net.ipv4.conf.default.accept_source_route = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.default.accept_source_route to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.default.accept_source_route = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Accepting ICMP Redirects By Defaultrule
To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.accept_redirects = 0
identifiers:
CCE-27015-7, DISA FSO RHEL-06-000091 references:
AC-4, CM-7, SC-5, SC-7, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects=0
#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.accept_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.accept_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.default.accept_redirects.*/net.ipv4.conf.default.accept_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.default.accept_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.default.accept_redirects = 0" >> /etc/sysctl.conf
fi
|
Disable Kernel Parameter for Accepting Secure Redirects By Defaultrule
To set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.secure_redirects = 0
identifiers:
CCE-26831-8, DISA FSO RHEL-06-000090 references:
AC-4, CM-7, SC-5, SC-7, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects=0
#
# If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.secure_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.secure_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.default.secure_redirects.*/net.ipv4.conf.default.secure_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.default.secure_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.default.secure_redirects = 0" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requestsrule
To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.icmp_echo_ignore_broadcasts = 1
identifiers:
CCE-26883-9, DISA FSO RHEL-06-000092 references:
CM-7, SC-5, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
/sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts=1
#
# If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.icmp_echo_ignore_broadcasts = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.icmp_echo_ignore_broadcasts /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.icmp_echo_ignore_broadcasts.*/net.ipv4.icmp_echo_ignore_broadcasts = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.icmp_echo_ignore_broadcasts to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.icmp_echo_ignore_broadcasts = 1" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Ignore Bogus ICMP Error Responsesrule
To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.icmp_ignore_bogus_error_responses = 1
identifiers:
CCE-26993-6, DISA FSO RHEL-06-000093 references:
CM-7, SC-5, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
/sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses=1
#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.icmp_ignore_bogus_error_responses = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.icmp_ignore_bogus_error_responses /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.icmp_ignore_bogus_error_responses.*/net.ipv4.icmp_ignore_bogus_error_responses = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.icmp_ignore_bogus_error_responses to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.icmp_ignore_bogus_error_responses = 1" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Use TCP Syncookiesrule
To set the runtime status of the net.ipv4.tcp_syncookies kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.tcp_syncookies=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.tcp_syncookies = 1
identifiers:
CCE-27053-8, DISA FSO RHEL-06-000095 references:
AC-4, SC-5(2), SC-5(3), 1092, 1095, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.tcp_syncookies
#
/sbin/sysctl -q -n -w net.ipv4.tcp_syncookies=1
#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.tcp_syncookies = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.tcp_syncookies /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.tcp_syncookies.*/net.ipv4.tcp_syncookies = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.tcp_syncookies to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.tcp_syncookies = 1" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Use Reverse Path Filtering for All Interfacesrule
To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.rp_filter = 1
identifiers:
CCE-26979-5, DISA FSO RHEL-06-000096 references:
AC-4, SC-5, SC-7, 1551, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.all.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter=1
#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.conf.all.rp_filter = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.rp_filter /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.all.rp_filter.*/net.ipv4.conf.all.rp_filter = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.all.rp_filter to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.rp_filter = 1" >> /etc/sysctl.conf
fi
|
Enable Kernel Parameter to Use Reverse Path Filtering by Defaultrule
To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.rp_filter = 1
identifiers:
CCE-26915-9, DISA FSO RHEL-06-000097 references:
AC-4, SC-5, SC-7, Test attestation on 20121024 by DS Remediation script:#
# Set runtime for net.ipv4.conf.default.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter=1
#
# If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to "1"
# else, add "net.ipv4.conf.default.rp_filter = 1" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.rp_filter /etc/sysctl.conf ; then
sed -i 's/^net.ipv4.conf.default.rp_filter.*/net.ipv4.conf.default.rp_filter = 1/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv4.conf.default.rp_filter to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.conf.default.rp_filter = 1" >> /etc/sysctl.conf
fi
|
Wireless NetworkinggroupWireless networking, such as 802.11
(WiFi) and Bluetooth, can present a security risk to sensitive or
classified systems and networks. Wireless networking hardware is
much more likely to be included in laptop or portable systems than
in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless
capability remains disabled. Acquisition policies often include provisions to
prevent the purchase of equipment that will be used in sensitive spaces and
includes wireless capabilities. If it is impractical to remove the wireless
hardware, and policy permits the device to enter sensitive spaces as long
as wireless is disabled, efforts should instead focus on disabling wireless capability
via software. |
contains 4 rules |
Disable Wireless Through Software ConfigurationgroupIf it is impossible to remove the wireless hardware
from the device in question, disable as much of it as possible
through software. The following methods can disable software
support for wireless networking, but note that these methods do not
prevent malicious software or careless users from re-activating the
devices. |
contains 4 rules |
Disable WiFi or Bluetooth in BIOSruleSome systems that include built-in wireless support offer the
ability to disable the device through the BIOS. This is system-specific;
consult your hardware manual or explore the BIOS setup during
boot. identifiers:
CCE-26878-9 references:
AC-18(a), AC-18(d), AC-18(3), CM-7, 85 |
Deactivate Wireless Network InterfacesruleDeactivating wireless network interfaces should prevent
normal usage of the wireless capability.
First, identify the interfaces available with the command:
$ ifconfig -a
Additionally, the following command may be used to
determine whether wireless support is included for a
particular interface, though this may not always be a clear
indicator:
$ iwconfig
After identifying any wireless interfaces (which may have
names like wlan0, ath0, wifi0, em1 or
eth0), deactivate the interface with the command:
$ sudo ifdown interface
These changes will only last until the next reboot. To
disable the interface for future boots, remove the appropriate
interface file from /etc/sysconfig/network-scripts:
$ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface
identifiers:
CCE-27057-9 references:
AC-18(a), AC-18(d), AC-18(3), CM-7, 85, Test attestation on 20121025 by DS |
Disable Bluetooth Servicerule
The bluetooth service can be disabled with the following command:
$ sudo chkconfig bluetooth off
$ sudo service bluetooth stop
identifiers:
CCE-27081-9, DISA FSO RHEL-06-000331 references:
AC-18(a), AC-18(d), AC-18(3), CM-7, 85, 1551, Test attestation on 20121025 by DS Remediation script:#
# Disable bluetooth for all run levels
#
/sbin/chkconfig --level 0123456 bluetooth off
#
# Stop bluetooth if currently running
#
/sbin/service bluetooth stop
|
Disable Bluetooth Kernel ModulesruleThe kernel's module loading system can be configured to prevent
loading of the Bluetooth module. Add the following to
the appropriate /etc/modprobe.d configuration file
to prevent the loading of the Bluetooth module:
install bluetooth /bin/true
identifiers:
CCE-26763-3, DISA FSO RHEL-06-000315 references:
AC-18(a), AC-18(d), AC-18(3), CM-7, 85, 1551, Test attestation on 20141031 by JL Remediation script:echo "install bluetooth /bin/true" > /etc/modprobe.d/bluetooth.conf
|
IPv6groupThe system includes support for Internet Protocol
version 6. A major and often-mentioned improvement over IPv4 is its
enormous increase in the number of available addresses. Another
important feature is its support for automatic configuration of
many network settings. |
contains 8 rules |
Disable Support for IPv6 Unless Neededgroup
Despite configuration that suggests support for IPv6 has
been disabled, link-local IPv6 address auto-configuration occurs
even when only an IPv4 address is assigned. The only way to
effectively prevent execution of the IPv6 networking stack is to
instruct the system not to activate the IPv6 kernel module.
|
contains 3 rules |
Disable IPv6 Networking Support Automatic LoadingruleTo prevent the IPv6 kernel module (ipv6) from binding to the
IPv6 networking stack, add the following line to
/etc/modprobe.d/disabled.conf (or another file in
/etc/modprobe.d):
options ipv6 disable=1
This permits the IPv6 module to be loaded (and thus satisfy other modules that
depend on it), while disabling support for the IPv6 protocol.
identifiers:
CCE-27153-6, DISA FSO RHEL-06-000098 references:
CM-7, 1551, Test attestation on 20121024 by DS Remediation script:
# Prevent the IPv6 kernel module (ipv6) from loading the IPv6 networking stack
echo "options ipv6 disable=1" > /etc/modprobe.d/ipv6.conf
# Since according to: https://access.redhat.com/solutions/72733
# "ipv6 disable=1" options doesn't always disable the IPv6 networking stack from
# loading, instruct also sysctl configuration to disable IPv6 according to:
# https://access.redhat.com/solutions/8709#rhel6disable
declare -a IPV6_SETTINGS=("net.ipv6.conf.all.disable_ipv6" "net.ipv6.conf.default.disable_ipv6")
for setting in ${IPV6_SETTINGS[@]}
do
# Set runtime =1 for setting
/sbin/sysctl -q -n -w "$setting=1"
# If setting is present in /etc/sysctl.conf, change value to "1"
# else, add "$setting = 1" to /etc/sysctl.conf
if grep -q ^"$setting" /etc/sysctl.conf ; then
sed -i "s/^$setting.*/$setting = 1/g" /etc/sysctl.conf
else
echo "" >> /etc/sysctl.conf
echo "# Set $setting = 1 per security requirements" >> /etc/sysctl.conf
echo "$setting = 1" >> /etc/sysctl.conf
fi
done
|
Disable Interface Usage of IPv6ruleTo disable interface usage of IPv6, add or correct the following lines in /etc/sysconfig/network:
NETWORKING_IPV6=no
IPV6INIT=no
identifiers:
CCE-27161-9 |
Disable Support for RPC IPv6ruleRPC services for NFSv4 try to load transport modules for
udp6 and tcp6 by default, even if IPv6 has been disabled in
/etc/modprobe.d. To prevent RPC services such as rpc.mountd
from attempting to start IPv6 network listeners, remove or comment out the
following two lines in /etc/netconfig:
udp6 tpi_clts v inet6 udp - -
tcp6 tpi_cots_ord v inet6 tcp - -
identifiers:
CCE-27232-8 references:
CM-7 Remediation script:
# Drop 'tcp6' and 'udp6' entries from /etc/netconfig to prevent RPC
# services for NFSv4 from attempting to start IPv6 network listeners
declare -a IPV6_RPC_ENTRIES=("tcp6" "udp6")
for rpc_entry in ${IPV6_RPC_ENTRIES[@]}
do
sed -i "/^$rpc_entry[[:space:]]\+tpi\_.*inet6.*/d" /etc/netconfig
done
|
Configure IPv6 Settings if NecessarygroupA major feature of IPv6 is the extent to which systems
implementing it can automatically configure their networking
devices using information from the network. From a security
perspective, manually configuring important configuration
information is preferable to accepting it from the network
in an unauthenticated fashion. |
contains 5 rules |
Disable Automatic ConfigurationgroupDisable the system's acceptance of router
advertisements and redirects by adding or correcting the following
line in /etc/sysconfig/network (note that this does not disable
sending router solicitations):
IPV6_AUTOCONF=no
|
contains 2 rules |
Disable Accepting IPv6 Router Advertisementsrule
To set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv6.conf.default.accept_ra = 0
identifiers:
CCE-27164-3 references:
CM-7 Remediation script:#
# Set runtime for net.ipv6.conf.default.accept_ra
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra=0
#
# If net.ipv6.conf.default.accept_ra present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv6.conf.default.accept_ra = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv6.conf.default.accept_ra /etc/sysctl.conf ; then
sed -i 's/^net.ipv6.conf.default.accept_ra.*/net.ipv6.conf.default.accept_ra = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv6.conf.default.accept_ra to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv6.conf.default.accept_ra = 0" >> /etc/sysctl.conf
fi
|
Disable Accepting IPv6 Redirectsrule
To set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter,
run the following command:
$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv6.conf.default.accept_redirects = 0
identifiers:
CCE-27166-8, DISA FSO RHEL-06-000099 references:
CM-7, 1551 Remediation script:#
# Set runtime for net.ipv6.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects=0
#
# If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv6.conf.default.accept_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv6.conf.default.accept_redirects /etc/sysctl.conf ; then
sed -i 's/^net.ipv6.conf.default.accept_redirects.*/net.ipv6.conf.default.accept_redirects = 0/g' /etc/sysctl.conf
else
echo -e "\n# Set net.ipv6.conf.default.accept_redirects to 0 per security requirements" >> /etc/sysctl.conf
echo "net.ipv6.conf.default.accept_redirects = 0" >> /etc/sysctl.conf
fi
|
Manually Assign Global IPv6 AddressruleTo manually assign an IP address for an interface, edit the
file /etc/sysconfig/network-scripts/ifcfg-interface. Add or correct the
following line (substituting the correct IPv6 address):
IPV6ADDR=2001:0DB8::ABCD/64
Manually assigning an IP address is preferable to accepting one from routers or
from the network otherwise. The example address here is an IPv6 address
reserved for documentation purposes, as defined by RFC3849.
identifiers:
CCE-27233-6 references:
CM-6(b) |
Use Privacy Extensions for AddressruleTo introduce randomness into the automatic generation of IPv6
addresses, add or correct the following line in
/etc/sysconfig/network-scripts/ifcfg-interface:
IPV6_PRIVACY=rfc3041
Automatically-generated IPv6 addresses are based on the underlying hardware
(e.g. Ethernet) address, and so it becomes possible to track a piece of
hardware over its lifetime using its traffic. If it is important for a system's
IP address to not trivially reveal its hardware address, this setting should be
applied.
identifiers:
CCE-27154-4 references:
CM-6(b) |
Manually Assign IPv6 Router AddressruleEdit the file
/etc/sysconfig/network-scripts/ifcfg-interface, and add or correct
the following line (substituting your gateway IP as appropriate):
IPV6_DEFAULTGW=2001:0DB8::0001
Router addresses should be manually set and not accepted via any
auto-configuration or router advertisement.
identifiers:
CCE-27234-4 references:
CM-6(b) |
Uncommon Network ProtocolsgroupThe system includes support for several network
protocols which are not commonly used. Although security vulnerabilities
in kernel networking code are not frequently
discovered, the consequences can be dramatic. Ensuring uncommon
network protocols are disabled reduces the system's risk to attacks
targeted at its implementation of those protocols. |
contains 4 rules |
Disable DCCP Supportrule
The Datagram Congestion Control Protocol (DCCP) is a
relatively new transport layer protocol, designed to support
streaming media and telephony.
To configure the system to prevent the dccp
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install dccp /bin/true
identifiers:
CCE-26448-1, DISA FSO RHEL-06-000124 references:
CM-7, 382, Test attestation on 20121024 by DS Remediation script:echo "install dccp /bin/true" > /etc/modprobe.d/dccp.conf
|
Disable SCTP Supportrule
The Stream Control Transmission Protocol (SCTP) is a
transport layer protocol, designed to support the idea of
message-oriented communication, with several streams of messages
within one connection.
To configure the system to prevent the sctp
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install sctp /bin/true
identifiers:
CCE-26410-1, DISA FSO RHEL-06-000125 references:
CM-7, 382, Test attestation on 20121024 by DS Remediation script:echo "install sctp /bin/true" > /etc/modprobe.d/sctp.conf
|
Disable RDS Supportrule
The Reliable Datagram Sockets (RDS) protocol is a transport
layer protocol designed to provide reliable high- bandwidth,
low-latency communications between nodes in a cluster.
To configure the system to prevent the rds
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install rds /bin/true
identifiers:
CCE-26239-4, DISA FSO RHEL-06-000126 references:
CM-7, 382, Test attestation on 20121024 by DS Remediation script:echo "install rds /bin/true" > /etc/modprobe.d/rds.conf
|
Disable TIPC Supportrule
The Transparent Inter-Process Communication (TIPC) protocol
is designed to provide communications between nodes in a
cluster.
To configure the system to prevent the tipc
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:
install tipc /bin/true
identifiers:
CCE-26696-5, DISA FSO RHEL-06-000127 references:
CM-7, 382, Test attestation on 20121024 by DS Remediation script:echo "install tipc /bin/true" > /etc/modprobe.d/tipc.conf
|
IPSec SupportgroupSupport for Internet Protocol Security (IPsec)
is provided in Red Hat Enterprise Linux 6 with Openswan.
|
contains 1 rule |
Install openswan PackageruleThe Openswan package provides an implementation of IPsec
and IKE, which permits the creation of secure tunnels over
untrusted networks.
The openswan package can be installed with the following command:
$ sudo yum install openswan
identifiers:
CCE-27626-1, DISA FSO RHEL-06-000321 references:
AC-17, MA-4, SC-8, 1130, 1131 Remediation script:yum -y install openswan
|
Disable Zeroconf NetworkingruleZeroconf networking allows the system to assign itself an IP
address and engage in IP communication without a statically-assigned address or
even a DHCP server. Automatic address assignment via Zeroconf (or DHCP) is not
recommended. To disable Zeroconf automatic route assignment in the 169.254.0.0
subnet, add or correct the following line in /etc/sysconfig/network:
NOZEROCONF=yes
identifiers:
CCE-27151-0 references:
CM-7 Remediation script:echo "NOZEROCONF=yes" >> /etc/sysconfig/network
|
Ensure System is Not Acting as a Network SnifferruleThe system should not be acting as a network sniffer, which can
capture all traffic on the network to which it is connected. Run the following
to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
identifiers:
CCE-27152-8 references:
CM-7, MA-3 |
Configure SysloggroupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
In Red Hat Enterprise Linux 6, rsyslog has replaced ksyslogd as the
syslog daemon of choice, and it includes some additional security features
such as reliable, connection-oriented (i.e. TCP) transmission of logs, the
option to log to database formats, and the encryption of log data en route to
a central logging server.
This section discusses how to configure rsyslog for
best effect, and how to use tools provided with the system to maintain and
monitor logs. |
contains 10 rules |
Ensure Proper Configuration of Log Filesgroup
The file /etc/rsyslog.conf controls where log message are written.
These are controlled by lines called rules, which consist of a
selector and an action.
These rules are often customized depending on the role of the system, the
requirements of the environment, and whatever may enable
the administrator to most effectively make use of log data.
The default rules in Red Hat Enterprise Linux 6 are:
*.info;mail.none;authpriv.none;cron.none /var/log/messages
authpriv.* /var/log/secure
mail.* -/var/log/maillog
cron.* /var/log/cron
*.emerg *
uucp,news.crit /var/log/spooler
local7.* /var/log/boot.log
See the man page rsyslog.conf(5) for more information.
Note that the rsyslog daemon can be configured to use a timestamp format that
some log processing programs may not understand. If this occurs,
edit the file /etc/rsyslog.conf and add or edit the following line:
$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
|
contains 3 rules |
Ensure Log Files Are Owned By Appropriate UserruleThe owner of all log files written by
rsyslog should be root.
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log.
For each log file LOGFILE referenced in /etc/rsyslog.conf,
run the following command to inspect the file's owner:
$ ls -l LOGFILE
If the owner is not root, run the following command to
correct this:
$ sudo chown root LOGFILE
identifiers:
CCE-26812-8, DISA FSO RHEL-06-000133 references:
AC-6, SI-11, 1314, Test attestation on 20121024 by DS |
Ensure Log Files Are Owned By Appropriate GroupruleThe group-owner of all log files written by
rsyslog should be root.
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log.
For each log file LOGFILE referenced in /etc/rsyslog.conf,
run the following command to inspect the file's group owner:
$ ls -l LOGFILE
If the owner is not root, run the following command to
correct this:
$ sudo chgrp root LOGFILE
identifiers:
CCE-26821-9, DISA FSO RHEL-06-000134 references:
AC-6, SI-11, 1314, Test attestation on 20121024 by DS |
Ensure System Log Files Have Correct PermissionsruleThe file permissions for all log files written by
rsyslog should be set to 600, or more restrictive.
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log.
For each log file LOGFILE referenced in /etc/rsyslog.conf,
run the following command to inspect the file's permissions:
$ ls -l LOGFILE
If the permissions are not 600 or more restrictive,
run the following command to correct this:
$ sudo chmod 0600 LOGFILE
identifiers:
CCE-27190-8, DISA FSO RHEL-06-000135 references:
SI-11, 1314, Test attestation on 20121024 by DS |
Rsyslog Logs Sent To Remote Hostgroup
If system logs are to be useful in detecting malicious
activities, it is necessary to send logs to a remote server. An
intruder who has compromised the root account on a machine may
delete the log entries which indicate that the system was attacked
before they are seen by an administrator.
However, it is recommended that logs be stored on the local
host in addition to being sent to the loghost, especially if
rsyslog has been configured to use the UDP protocol to send
messages over a network. UDP does not guarantee reliable delivery,
and moderately busy sites will lose log messages occasionally,
especially in periods of high traffic which may be the result of an
attack. In addition, remote rsyslog messages are not
authenticated in any way by default, so it is easy for an attacker to
introduce spurious messages to the central log server. Also, some
problems cause loss of network connectivity, which will prevent the
sending of messages to the central server. For all of these reasons, it is
better to store log messages both centrally and on each host, so
that they can be correlated if necessary. |
contains 1 rule |
Ensure Logs Sent To Remote Hostrule
To configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting loghost.example.com appropriately.
The choice of protocol depends on the environment of the system;
although TCP and RELP provide more reliable message delivery,
they may not be supported in all environments.
To use UDP for log message delivery:
*.* @loghost.example.com
To use TCP for log message delivery:
*.* @@loghost.example.com
To use RELP for log message delivery:
*.* :omrelp:loghost.example.com
identifiers:
CCE-26801-1, DISA FSO RHEL-06-000136 references:
AU-3(2), AU-9, 1348, 136 |
Configure rsyslogd to Accept Remote Messages If Acting as a Log Servergroup
By default, rsyslog does not listen over the network
for log messages. If needed, modules can be enabled to allow
the rsyslog daemon to receive messages from other systems and for the system
thus to act as a log server.
If the machine is not a log server, then lines concerning these modules
should remain commented out.
|
contains 1 rule |
Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log ServerruleThe rsyslog daemon should not accept remote messages
unless the system acts as a log server.
To ensure that it is not listening on the network, ensure the following lines are
not found in /etc/rsyslog.conf:
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port
identifiers:
CCE-26803-7 references:
AU-9(2), AC-4 |
Ensure All Logs are Rotated by logrotategroupEdit the file /etc/logrotate.d/syslog. Find the first
line, which should look like this (wrapped for clarity):
/var/log/messages /var/log/secure /var/log/maillog /var/log/spooler \
/var/log/boot.log /var/log/cron {
Edit this line so that it contains a one-space-separated
listing of each log file referenced in /etc/rsyslog.conf.
All logs in use on a system must be rotated regularly, or the
log files will consume disk space over time, eventually interfering
with system operation. The file /etc/logrotate.d/syslog is the
configuration file used by the logrotate program to maintain all
log files written by syslog. By default, it rotates logs weekly and
stores four archival copies of each log. These settings can be
modified by editing /etc/logrotate.conf, but the defaults are
sufficient for purposes of this guide.
Note that logrotate is run nightly by the cron job
/etc/cron.daily/logrotate. If particularly active logs need to be
rotated more often than once a day, some other mechanism must be
used. |
contains 1 rule |
Ensure Logrotate Runs PeriodicallyruleThe logrotate utility allows for the automatic rotation of
log files. The frequency of rotation is specified in /etc/logrotate.conf,
which triggers a cron task. To configure logrotate to run daily, add or correct
the following line in /etc/logrotate.conf:
# rotate log files frequency
daily
identifiers:
CCE-27014-0, DISA FSO RHEL-06-000138 references:
AU-9, 366 |
Configure Logwatch on the Central Log Servergroup
Is this machine the central log server? If so, edit the file /etc/logwatch/conf/logwatch.conf as shown below.
|
contains 1 rule |
Configure Logwatch SplitHosts Linerule
If SplitHosts is set, Logwatch will separate entries by hostname. This makes the report longer but significantly
more usable. If it is not set, then Logwatch will not report which host generated a given log entry, and that
information is almost always necessary
SplitHosts = yes identifiers:
CCE-27069-4 |
Ensure rsyslog is Installedrule
Rsyslog is installed by default.
The rsyslog package can be installed with the following command:
$ sudo yum install rsyslog
identifiers:
CCE-26809-4 references:
AU-9(2), 1311, 1312, Test attestation on 20121024 by DS Remediation script:yum -y install rsyslog
|
Enable rsyslog ServiceruleThe rsyslog service provides syslog-style logging by default on Red Hat Enterprise Linux 6.
The rsyslog service can be enabled with the following command:
$ sudo chkconfig --level 2345 rsyslog on
identifiers:
CCE-26807-8 references:
AU-12, 1557, 1312, 1311, Test attestation on 20121024 by DS Remediation script:#
# Enable rsyslog for all run levels
#
/sbin/chkconfig --level 0123456 rsyslog on
#
# Start rsyslog if not currently running
#
/sbin/service rsyslog start
|
Disable Logwatch on Clients if a Logserver Existsrule
Does your site have a central logserver which has been configured to report on logs received from all systems?
If so:
$ sudo rm /etc/cron.daily/0logwatch
If no logserver exists, it will be necessary for each machine to run Logwatch individually. Using a central
logserver provides the security and reliability benefits discussed earlier, and also makes monitoring logs easier
and less time-intensive for administrators. identifiers:
CCE-27162-7 |
System Accounting with auditdgroupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, auditd has modest disk space
requirements, and should not noticeably impact system performance.
Government networks often have substantial auditing
requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Fedora Documentation available at
http://docs.fedoraproject.org/en-US/Fedora/13/html/Security-Enhanced_Linux/sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages.html
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file
type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
msg=audit(1226874073.147:96)The number in parentheses is the unformatted time stamp (Epoch time)
for the event, which can be converted to standard time by using the
date command.
{ getattr }The item in braces indicates the permission that was denied. getattr
indicates the source process was trying to read the target file's status information.
This occurs before reading files. This action is denied due to the file being
accessed having the wrong label. Commonly seen permissions include getattr,
read, and write.comm="httpd"The executable that launched the process. The full path of the executable is
found in the exe= section of the system call (SYSCALL) message,
which in this case, is exe="/usr/sbin/httpd".
path="/var/www/html/file1"The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0"The SELinux context of the process that attempted the denied action. In
this case, it is the SELinux context of the Apache HTTP Server, which is running
in the httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0"The SELinux context of the object (target) the process attempted to access.
In this case, it is the SELinux context of file1. Note: the samba_share_t
type is not accessible to processes running in the httpd_t domain. From the system call (SYSCALL) message, two items are of interest:
success=no: indicates whether the denial (AVC) was enforced or not.
success=no indicates the system call was not successful (SELinux denied
access). success=yes indicates the system call was successful - this can
be seen for permissive domains or unconfined domains, such as initrc_t
and kernel_t.
exe="/usr/sbin/httpd": the full path to the executable that launched
the process, which in this case, is exe="/usr/sbin/httpd".
|
contains 31 rules |
Configure auditd Rules for Comprehensive AuditinggroupThe auditd program can perform comprehensive
monitoring of system activity. This section describes recommended
configuration settings for comprehensive auditing, but a full
description of the auditing system's capabilities is beyond the
scope of this guide. The mailing list linux-audit@redhat.com exists
to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:
Tracing of arbitrary system calls (identified by name or number)
on entry or exit.Filtering by PID, UID, call success, system call argument (with
some limitations), etc.Monitoring of specific files for modifications to the file's
contents or metadata.
Auditing rules at startup are controlled by the file /etc/audit/audit.rules.
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and
editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart
|
contains 31 rules |
Records Events that Modify Date and Time InformationgroupArbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time. All changes to the system
time should be audited. |
contains 5 rules |
Record attempts to alter time through adjtimexruleOn a 32-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
On a 64-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime
-k audit_time_rules
identifiers:
CCE-26242-8, DISA FSO RHEL-06-000165 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 Remediation script:
# audit.rules file to operate at
AUDIT_RULES_FILE="/etc/audit/audit.rules"
# General form / skeleton of an audit rule to search for
BASE_SEARCH_RULE='-a always,exit .* -k audit_time_rules'
# System calls group to search for
SYSCALL_GROUP="time"
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && ARCHS=("b32") || ARCHS=("b32" "b64")
# Perform the remediation depending on the system's architecture:
# * on 32 bit system, operate just at '-F arch=b32' audit rules
# * on 64 bit system, operate at both '-F arch=b32' & '-F arch=b64' audit rules
for ARCH in ${ARCHS[@]}
do
# Create expected audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k audit_time_rules"
else
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules"
fi
# Indicator that we want to append $EXPECTED_RULE for key & arch into
# audit.rules by default
APPEND_EXPECTED_RULE=0
# From all the existing /etc/audit.rule definitions select those, which:
# * follow the common audit rule form ($BASE_SEARCH_RULE above)
# * meet the hardware architecture requirement, and
# * are current $SYSCALL_GROUP specific
IFS=$'\n' EXISTING_KEY_ARCH_RULES=($(sed -e "/${BASE_SEARCH_RULE}/!d" -e "/${ARCH}/!d" -e "/${SYSCALL_GROUP}/!d" ${AUDIT_RULES_FILE}))
# Process found rules case by case
for RULE in ${EXISTING_KEY_ARCH_RULES[@]}
do
# Found rule is for same arch & syscall group, but differs slightly (in count of -S arguments)
if [ ${RULE} != ${EXPECTED_RULE} ]
then
# If so, isolate just '-S syscall' substring of that rule
RULE_SYSCALLS=$(echo ${RULE} | grep -o -P '(-S \w+ )+')
# Check if list of '-S syscall' arguments of that rule is a subset
# '-S syscall' list from the expected form ($EXPECTED_RULE)
if [ $(echo ${EXPECTED_RULE} | grep -- ${RULE_SYSCALLS}) ]
then
# If so, this audit rule is covered when we append expected rule
# later & therefore the rule can be deleted.
#
# Thus delete the rule from both - the audit.rules file and
# our $EXISTING_KEY_ARCH_RULES array
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
EXISTING_KEY_ARCH_RULES=(${EXISTING_KEY_ARCH_RULES[@]//${RULE}/})
else
# Rule isn't covered by $EXPECTED_RULE - in other words it besides
# adjtimex, settimeofday, or stime -S arguments contains also -S argument
# for other time group system call (-S clock_adjtime for example).
# Example: '-S adjtimex -S clock_adjtime'
#
# Therefore:
# * delete the original rule for arch & key from audit.rules
# (original '-S adjtimex -S clock_adjtime' rule would be deleted)
# * delete $SYSCALL_GROUP -S arguments from the rule,
# but keep those not from this $SYSCALL_GROUP
# (original '-S adjtimex -S clock_adjtime' would become '-S clock_adjtime')
# * append the modified (filtered) rule again into audit.rules
# if the same rule not already present
# (new rule for same arch & key with '-S clock_adjtime' would be appended
# if not present yet)
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
if [ ${ARCH} = "b32" ]
then
# On 32-bit arch drop ' -S (adjtimex|settimeofday|stime)' from the rule's
# system call list
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday|stime)//g")
else
# On 64-bit arch drop ' -S (adjtimex|settimeofday)' from the rule's
# system call list ('stime' call isn't known, see "$ ausyscall .." examples above)
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday)//g")
fi
# Update the list of system calls for new rule to contain those from new syscalls list
UPDATED_RULE=$(echo ${RULE} | sed "s/${RULE_SYSCALLS}/${NEW_SYSCALLS_FOR_RULE}/g")
# Squeeze repeated whitespace characters in rule definition (if any) into one
UPDATED_RULE=$(echo ${UPDATED_RULE} | tr -s '[:space:]')
# Insert updated rule into /etc/audit/audit.rules only in case it's not
# present yet to prevent duplicate same rules
if [ ! $(grep -- ${UPDATED_RULE} ${AUDIT_RULES_FILE}) ]
then
echo ${UPDATED_RULE} >> ${AUDIT_RULES_FILE}
fi
fi
else
# /etc/audit/audit.rules already contains the expected rule form for this
# architecture & key => don't insert it second time
APPEND_EXPECTED_RULE=1
fi
done
# We deleted all rules that were subset of the expected one for this arch & key.
# Also isolated rules containing system calls not from this system calls group.
# Now append the expected rule if it's not present in audit.rules yet
if [[ ${APPEND_EXPECTED_RULE} -eq "0" ]]
then
echo ${EXPECTED_RULE} >> ${AUDIT_RULES_FILE}
fi
done
|
Record attempts to alter time through settimeofdayruleOn a 32-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
On a 64-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime
-k audit_time_rules
identifiers:
CCE-27203-9, DISA FSO RHEL-06-000167 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 Remediation script:
# audit.rules file to operate at
AUDIT_RULES_FILE="/etc/audit/audit.rules"
# General form / skeleton of an audit rule to search for
BASE_SEARCH_RULE='-a always,exit .* -k audit_time_rules'
# System calls group to search for
SYSCALL_GROUP="time"
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && ARCHS=("b32") || ARCHS=("b32" "b64")
# Perform the remediation depending on the system's architecture:
# * on 32 bit system, operate just at '-F arch=b32' audit rules
# * on 64 bit system, operate at both '-F arch=b32' & '-F arch=b64' audit rules
for ARCH in ${ARCHS[@]}
do
# Create expected audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k audit_time_rules"
else
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules"
fi
# Indicator that we want to append $EXPECTED_RULE for key & arch into
# audit.rules by default
APPEND_EXPECTED_RULE=0
# From all the existing /etc/audit.rule definitions select those, which:
# * follow the common audit rule form ($BASE_SEARCH_RULE above)
# * meet the hardware architecture requirement, and
# * are current $SYSCALL_GROUP specific
IFS=$'\n' EXISTING_KEY_ARCH_RULES=($(sed -e "/${BASE_SEARCH_RULE}/!d" -e "/${ARCH}/!d" -e "/${SYSCALL_GROUP}/!d" ${AUDIT_RULES_FILE}))
# Process found rules case by case
for RULE in ${EXISTING_KEY_ARCH_RULES[@]}
do
# Found rule is for same arch & syscall group, but differs slightly (in count of -S arguments)
if [ ${RULE} != ${EXPECTED_RULE} ]
then
# If so, isolate just '-S syscall' substring of that rule
RULE_SYSCALLS=$(echo ${RULE} | grep -o -P '(-S \w+ )+')
# Check if list of '-S syscall' arguments of that rule is a subset
# '-S syscall' list from the expected form ($EXPECTED_RULE)
if [ $(echo ${EXPECTED_RULE} | grep -- ${RULE_SYSCALLS}) ]
then
# If so, this audit rule is covered when we append expected rule
# later & therefore the rule can be deleted.
#
# Thus delete the rule from both - the audit.rules file and
# our $EXISTING_KEY_ARCH_RULES array
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
EXISTING_KEY_ARCH_RULES=(${EXISTING_KEY_ARCH_RULES[@]//${RULE}/})
else
# Rule isn't covered by $EXPECTED_RULE - in other words it besides
# adjtimex, settimeofday, or stime -S arguments contains also -S argument
# for other time group system call (-S clock_adjtime for example).
# Example: '-S adjtimex -S clock_adjtime'
#
# Therefore:
# * delete the original rule for arch & key from audit.rules
# (original '-S adjtimex -S clock_adjtime' rule would be deleted)
# * delete $SYSCALL_GROUP -S arguments from the rule,
# but keep those not from this $SYSCALL_GROUP
# (original '-S adjtimex -S clock_adjtime' would become '-S clock_adjtime')
# * append the modified (filtered) rule again into audit.rules
# if the same rule not already present
# (new rule for same arch & key with '-S clock_adjtime' would be appended
# if not present yet)
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
if [ ${ARCH} = "b32" ]
then
# On 32-bit arch drop ' -S (adjtimex|settimeofday|stime)' from the rule's
# system call list
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday|stime)//g")
else
# On 64-bit arch drop ' -S (adjtimex|settimeofday)' from the rule's
# system call list ('stime' call isn't known, see "$ ausyscall .." examples above)
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday)//g")
fi
# Update the list of system calls for new rule to contain those from new syscalls list
UPDATED_RULE=$(echo ${RULE} | sed "s/${RULE_SYSCALLS}/${NEW_SYSCALLS_FOR_RULE}/g")
# Squeeze repeated whitespace characters in rule definition (if any) into one
UPDATED_RULE=$(echo ${UPDATED_RULE} | tr -s '[:space:]')
# Insert updated rule into /etc/audit/audit.rules only in case it's not
# present yet to prevent duplicate same rules
if [ ! $(grep -- ${UPDATED_RULE} ${AUDIT_RULES_FILE}) ]
then
echo ${UPDATED_RULE} >> ${AUDIT_RULES_FILE}
fi
fi
else
# /etc/audit/audit.rules already contains the expected rule form for this
# architecture & key => don't insert it second time
APPEND_EXPECTED_RULE=1
fi
done
# We deleted all rules that were subset of the expected one for this arch & key.
# Also isolated rules containing system calls not from this system calls group.
# Now append the expected rule if it's not present in audit.rules yet
if [[ ${APPEND_EXPECTED_RULE} -eq "0" ]]
then
echo ${EXPECTED_RULE} >> ${AUDIT_RULES_FILE}
fi
done
|
Record Attempts to Alter Time Through stimeruleOn a 32-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b32 -S stime -k audit_time_rules
On a 64-bit system, the "-S stime" is not necessary. The -k option allows for
the specification of a key in string form that can be used for better
reporting capability through ausearch and aureport. Multiple system calls
can be defined on the same line to save space if desired, but is not required.
See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime
-k audit_time_rules
identifiers:
CCE-27169-2, DISA FSO RHEL-06-000169 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 Remediation script:
# audit.rules file to operate at
AUDIT_RULES_FILE="/etc/audit/audit.rules"
# General form / skeleton of an audit rule to search for
BASE_SEARCH_RULE='-a always,exit .* -k audit_time_rules'
# System calls group to search for
SYSCALL_GROUP="time"
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && ARCHS=("b32") || ARCHS=("b32" "b64")
# Perform the remediation depending on the system's architecture:
# * on 32 bit system, operate just at '-F arch=b32' audit rules
# * on 64 bit system, operate at both '-F arch=b32' & '-F arch=b64' audit rules
for ARCH in ${ARCHS[@]}
do
# Create expected audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k audit_time_rules"
else
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
EXPECTED_RULE="-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules"
fi
# Indicator that we want to append $EXPECTED_RULE for key & arch into
# audit.rules by default
APPEND_EXPECTED_RULE=0
# From all the existing /etc/audit.rule definitions select those, which:
# * follow the common audit rule form ($BASE_SEARCH_RULE above)
# * meet the hardware architecture requirement, and
# * are current $SYSCALL_GROUP specific
IFS=$'\n' EXISTING_KEY_ARCH_RULES=($(sed -e "/${BASE_SEARCH_RULE}/!d" -e "/${ARCH}/!d" -e "/${SYSCALL_GROUP}/!d" ${AUDIT_RULES_FILE}))
# Process found rules case by case
for RULE in ${EXISTING_KEY_ARCH_RULES[@]}
do
# Found rule is for same arch & syscall group, but differs slightly (in count of -S arguments)
if [ ${RULE} != ${EXPECTED_RULE} ]
then
# If so, isolate just '-S syscall' substring of that rule
RULE_SYSCALLS=$(echo ${RULE} | grep -o -P '(-S \w+ )+')
# Check if list of '-S syscall' arguments of that rule is a subset
# '-S syscall' list from the expected form ($EXPECTED_RULE)
if [ $(echo ${EXPECTED_RULE} | grep -- ${RULE_SYSCALLS}) ]
then
# If so, this audit rule is covered when we append expected rule
# later & therefore the rule can be deleted.
#
# Thus delete the rule from both - the audit.rules file and
# our $EXISTING_KEY_ARCH_RULES array
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
EXISTING_KEY_ARCH_RULES=(${EXISTING_KEY_ARCH_RULES[@]//${RULE}/})
else
# Rule isn't covered by $EXPECTED_RULE - in other words it besides
# adjtimex, settimeofday, or stime -S arguments contains also -S argument
# for other time group system call (-S clock_adjtime for example).
# Example: '-S adjtimex -S clock_adjtime'
#
# Therefore:
# * delete the original rule for arch & key from audit.rules
# (original '-S adjtimex -S clock_adjtime' rule would be deleted)
# * delete $SYSCALL_GROUP -S arguments from the rule,
# but keep those not from this $SYSCALL_GROUP
# (original '-S adjtimex -S clock_adjtime' would become '-S clock_adjtime')
# * append the modified (filtered) rule again into audit.rules
# if the same rule not already present
# (new rule for same arch & key with '-S clock_adjtime' would be appended
# if not present yet)
sed -i -e "/${RULE}/d" ${AUDIT_RULES_FILE}
if [ ${ARCH} = "b32" ]
then
# On 32-bit arch drop ' -S (adjtimex|settimeofday|stime)' from the rule's
# system call list
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday|stime)//g")
else
# On 64-bit arch drop ' -S (adjtimex|settimeofday)' from the rule's
# system call list ('stime' call isn't known, see "$ ausyscall .." examples above)
NEW_SYSCALLS_FOR_RULE=$(echo ${RULE_SYSCALLS} | sed -r -e "s/[\s]*-S (adjtimex|settimeofday)//g")
fi
# Update the list of system calls for new rule to contain those from new syscalls list
UPDATED_RULE=$(echo ${RULE} | sed "s/${RULE_SYSCALLS}/${NEW_SYSCALLS_FOR_RULE}/g")
# Squeeze repeated whitespace characters in rule definition (if any) into one
UPDATED_RULE=$(echo ${UPDATED_RULE} | tr -s '[:space:]')
# Insert updated rule into /etc/audit/audit.rules only in case it's not
# present yet to prevent duplicate same rules
if [ ! $(grep -- ${UPDATED_RULE} ${AUDIT_RULES_FILE}) ]
then
echo ${UPDATED_RULE} >> ${AUDIT_RULES_FILE}
fi
fi
else
# /etc/audit/audit.rules already contains the expected rule form for this
# architecture & key => don't insert it second time
APPEND_EXPECTED_RULE=1
fi
done
# We deleted all rules that were subset of the expected one for this arch & key.
# Also isolated rules containing system calls not from this system calls group.
# Now append the expected rule if it's not present in audit.rules yet
if [[ ${APPEND_EXPECTED_RULE} -eq "0" ]]
then
echo ${EXPECTED_RULE} >> ${AUDIT_RULES_FILE}
fi
done
|
Record Attempts to Alter Time Through clock_settimeruleOn a 32-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b32 -S clock_settime -k audit_time_rules
On a 64-bit system, add the following to /etc/audit/audit.rules:
# audit_time_rules
-a always,exit -F arch=b64 -S clock_settime -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime
-k audit_time_rules
identifiers:
CCE-27170-0, DISA FSO RHEL-06-000171 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -k audit_time_rules"
GROUP="clock_settime"
FULL_RULE="-a always,exit -F arch=$ARCH -S clock_settime -k audit_time_rules"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Attempts to Alter the localtime FileruleAdd the following to /etc/audit/audit.rules:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport and
should always be used.
identifiers:
CCE-27172-6, DISA FSO RHEL-06-000173 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation
fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
|
Record Events that Modify the System's Discretionary Access ControlsgroupAt a minimum, the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules:
-a always,exit -F arch=b32 -S chmod -S fchmod -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod
-a always,exit -F arch=b32 -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod
-a always,exit -F arch=b32 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod -S fchmod -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod
-a always,exit -F arch=b64 -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod
-a always,exit -F arch=b64 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
|
contains 13 rules |
Record Events that Modify the System's Discretionary Access Controls - chmodruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-26280-8, DISA FSO RHEL-06-000184 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chmod"
FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - chownruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27173-4, DISA FSO RHEL-06-000185 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chown"
FULL_RULE="-a always,exit -F arch=$ARCH -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fchmodruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27174-2, DISA FSO RHEL-06-000186 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chmod"
FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fchmodatruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27175-9, DISA FSO RHEL-06-000187 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chmod"
FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fchownruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27177-5, DISA FSO RHEL-06-000188 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chown"
FULL_RULE="-a always,exit -F arch=$ARCH -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fchownatruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27178-3, DISA FSO RHEL-06-000189 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chown"
FULL_RULE="-a always,exit -F arch=$ARCH -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27179-1, DISA FSO RHEL-06-000190 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27180-9, DISA FSO RHEL-06-000191 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - lchownruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27181-7, DISA FSO RHEL-06-000192 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="chown"
FULL_RULE="-a always,exit -F arch=$ARCH -S chown -S fchown -S fchownat -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27182-5, DISA FSO RHEL-06-000193 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27183-3, DISA FSO RHEL-06-000194 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - removexattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27184-1, DISA FSO RHEL-06-000195 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify the System's Discretionary Access Controls - setxattrruleAt a minimum the audit system should collect file
permission changes for all users and root. Add the following to
/etc/audit/audit.rules:
-a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod
identifiers:
CCE-27185-8, DISA FSO RHEL-06-000196 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="xattr"
FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Record Events that Modify User/Group InformationruleAdd the following to /etc/audit/audit.rules, in order
to capture events that modify account changes:
# audit_rules_usergroup_modification
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
identifiers:
CCE-26664-3, DISA FSO RHEL-06-000174 references:
AC-2(4), AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 18, 1403, 1404, 1405, 1684, 1683, 1685, 1686 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation
fix_audit_watch_rule "auditctl" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"
|
Record Events that Modify the System's Network EnvironmentruleAdd the following to /etc/audit/audit.rules, setting
ARCH to either b32 or b64 as appropriate for your system:
# audit_rules_networkconfig_modification
-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
identifiers:
CCE-26648-6, DISA FSO RHEL-06-000182 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -k *"
# Use escaped BRE regex to specify rule group
GROUP="set\(host\|domain\)name"
FULL_RULE="-a always,exit -F arch=$ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
# Then perform the remediations for the watch rules
fix_audit_watch_rule "auditctl" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"
|
System Audit Logs Must Have Mode 0640 or Less Permissiverule
Change the mode of the audit log files with the following command:
$ sudo chmod 0640 audit_file
identifiers:
CCE-27243-5, DISA FSO RHEL-06-000383 references:
AC-6, AU-1(b), AU-9, IR-5, 166, Test attestation on 20121024 by DS Remediation script:chmod -R 640 /var/log/audit/*
chmod 640 /etc/audit/audit.rules
|
System Audit Logs Must Be Owned By Rootrule
To properly set the owner of /var/log, run the command:
$ sudo chown root /var/log
identifiers:
CCE-27244-3, DISA FSO RHEL-06-000384 references:
AC-6, AU-1(b), AU-9, IR-5, 166, Test attestation on 20121024 by DS |
Record Events that Modify the System's Mandatory Access ControlsruleAdd the following to /etc/audit/audit.rules:
-w /etc/selinux/ -p wa -k MAC-policy
identifiers:
CCE-26657-7, DISA FSO RHEL-06-000183 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation
fix_audit_watch_rule "auditctl" "/etc/selinux/" "wa" "MAC-policy"
|
Record Attempts to Alter Login and Logout Eventsrule
The audit system already collects login info for all users and root. To watch for attempted manual edits of
files involved in storing login events, add the following to /etc/audit/audit.rules:
-w /var/log/faillog -p wa -k logins
-w /var/log/lastlog -p wa -k logins
identifiers:
CCE-26691-6 references:
AC-3(10), AU-1(b), AU-12(a), AU-12(c), IR-5 |
Record Attempts to Alter Process and Session Initiation Informationrule The audit system already collects process information for all
users and root. To watch for attempted manual edits of files involved in
storing such process information, add the following to
/etc/audit/audit.rules:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
identifiers:
CCE-26610-6 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation
fix_audit_watch_rule "auditctl" "/var/run/utmp" "wa" "session"
fix_audit_watch_rule "auditctl" "/var/log/btmp" "wa" "session"
fix_audit_watch_rule "auditctl" "/var/log/wtmp" "wa" "session"
|
Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)ruleAt a minimum the audit system should collect
unauthorized file accesses for all users and root. Add the following
to /etc/audit/audit.rules:
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access
If the system is 64 bit then also add the following:
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access
identifiers:
CCE-26712-0, DISA FSO RHEL-06-000197 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# First fix the -EACCES requirement
PATTERN="-a always,exit -F arch=$ARCH -S .* -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k *"
# Use escaped BRE regex to specify rule group
GROUP="\(creat\|open\|truncate\)"
FULL_RULE="-a always,exit -F arch=$ARCH -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
# Then fix the -EPERM requirement
PATTERN="-a always,exit -F arch=$ARCH -S .* -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k *"
# No need to change content of $GROUP variable - it's the same as for -EACCES case above
FULL_RULE="-a always,exit -F arch=$ARCH -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Ensure auditd Collects Information on the Use of Privileged CommandsruleAt a minimum the audit system should collect the
execution of privileged commands for all users and root.
To find the relevant setuid / setgid programs, run the following command
for each local partition PART:
$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
Then, for each setuid / setgid program on the system, add a line of the
following form to /etc/audit/audit.rules, where
SETUID_PROG_PATH is the full path to each setuid / setgid program
in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged
identifiers:
CCE-26457-2, DISA FSO RHEL-06-000198 references:
AC-3(10)), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AC-6(9), AU-12(a), AU-12(c), IR-5, 40, Test attestation on 20140703 by JL Remediation script:
readonly AUDIT_RULES='/etc/audit/audit.rules'
# Obtain the list of SUID/SGID binaries on the particular system into PRIVILEGED_BINARIES array
PRIVILEGED_BINARIES=($(find / -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null))
# Keep list of SUID/SGID binaries that have been already handled within some previous iteration
declare -a SBINARIES_TO_SKIP=()
# For each found binary from that list...
for SBINARY in ${PRIVILEGED_BINARIES[@]}
do
# Replace possible slash '/' character in SBINARY definition so we could use it in sed expressions below
SBINARY_ESC=${SBINARY//$'/'/$'\/'}
# Check if this SBINARY wasn't already handled in some of the previous iterations
if [[ $(sed -ne "/$SBINARY_ESC/p" <<< ${SBINARIES_TO_SKIP[@]}) ]]
then
# If so, don't process it second time & go to process next SBINARY
continue
fi
# Search existing audit.rule's content for match. Match criteria:
# * existing rule is for the same SUID/SGID binary we are currently processing (but
# can contain multiple -F path= elements covering multiple SUID/SGID binaries)
# * existing rule contains all arguments from expected rule form (though can contain
# them in arbitrary order)
BASE_SEARCH=$(sed -e "/-a always,exit/!d" -e "/-F path=${SBINARY_ESC}/!d" \
-e "/-F path=[^[:space:]]\+/!d" -e "/-F perm=.*/!d" \
-e "/-F auid>=500/!d" -e "/-F auid!=4294967295/!d" \
-e "/-k privileged/!d" $AUDIT_RULES)
# Define expected rule form for this binary
EXPECTED_RULE="-a always,exit -F path=${SBINARY} -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged"
# Require execute access type to be set for existing audit rule
EXEC_ACCESS='x'
# Search existing audit.rules content for presence of rule pattern for this binary
if [[ $BASE_SEARCH ]]
then
# Current /etc/audit/audit.rules already contains rule for this binary =>
# Store the exact form of found rule for this binary for further processing
CONCRETE_RULE=$BASE_SEARCH
# Select all other SUID/SGID binaries possibly also present in the found rule
IFS=$'\n' HANDLED_SBINARIES=($(grep -o -e "-F path=[^[:space:]]\+" <<< $CONCRETE_RULE))
IFS=$' ' HANDLED_SBINARIES=(${HANDLED_SBINARIES[@]//-F path=/})
# Merge the list of such SUID/SGID binaries found in this iteration with global list ignoring duplicates
SBINARIES_TO_SKIP=($(for i in "${SBINARIES_TO_SKIP[@]}" "${HANDLED_SBINARIES[@]}"; do echo $i; done | sort -du))
# Separate CONCRETE_RULE into three sections using hash '#'
# sign as a delimiter around rule's permission section borders
CONCRETE_RULE=$(echo $CONCRETE_RULE | sed -n "s/\(.*\)\+\(-F perm=[rwax]\+\)\+/\1#\2#/p")
# Split CONCRETE_RULE into head, perm, and tail sections using hash '#' delimiter
IFS=$'#' read RULE_HEAD RULE_PERM RULE_TAIL <<< "$CONCRETE_RULE"
# Extract already present exact access type [r|w|x|a] from rule's permission section
ACCESS_TYPE=${RULE_PERM//-F perm=/}
# Verify current permission access type(s) for rule contain 'x' (execute) permission
if ! grep -q "$EXEC_ACCESS" <<< "$ACCESS_TYPE"
then
# If not, append the 'x' (execute) permission to the existing access type bits
ACCESS_TYPE="$ACCESS_TYPE$EXEC_ACCESS"
# Reconstruct the permissions section for the rule
NEW_RULE_PERM="-F perm=$ACCESS_TYPE"
# Update existing rule in /etc/audit/audit.rules with the new permission section
sed -i "s#${RULE_HEAD}\(.*\)${RULE_TAIL}#${RULE_HEAD}${NEW_RULE_PERM}${RULE_TAIL}#" $AUDIT_RULES
fi
else
# Current /etc/audit/audit.rules content doesn't contain expected rule for this
# SUID/SGID binary yet => append it
echo $EXPECTED_RULE >> $AUDIT_RULES
fi
done
|
Ensure auditd Collects Information on Exporting to Media (successful)ruleAt a minimum the audit system should collect media
exportation events for all users and root. Add the following to
/etc/audit/audit.rules, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export
identifiers:
CCE-26573-6, DISA FSO RHEL-06-000199 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126, Test attestation on 20121024 by DS Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
GROUP="mount"
FULL_RULE="-a always,exit -F arch=$ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Ensure auditd Collects File Deletion Events by UserruleAt a minimum the audit system should collect file
deletion events for all users and root. Add the following to
/etc/audit/audit.rules, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete
identifiers:
CCE-26651-0, DISA FSO RHEL-06-000200 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in ${RULE_ARCHS[@]}
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k delete"
# Use escaped BRE regex to specify rule group
GROUP="\(rmdir\|unlink\|rename\)"
FULL_RULE="-a always,exit -F arch=$ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
|
Ensure auditd Collects Information on Kernel Module Loading and UnloadingruleAdd the following to /etc/audit/audit.rules in order
to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-w /sbin/insmod -p x -k modules
-w /sbin/rmmod -p x -k modules
-w /sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules
identifiers:
CCE-26611-4, DISA FSO RHEL-06-000202 references:
AC-3(10), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
# Include source function library.
. /usr/share/scap-security-guide/remediation_functions
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit kernel modules can't be loaded / unloaded on 64-bit kernel =>
# it's not required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule. Therefore for
# each system it's enought to check presence of system's native rule form.
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b64")
for ARCH in "${RULE_ARCHS[@]}"
do
PATTERN="-a always,exit -F arch=$ARCH -S .* -k *"
# Use escaped BRE regex to specify rule group
GROUP="\(init\|delete\)_module"
FULL_RULE="-a always,exit -F arch=$ARCH -S init_module -S delete_module -k modules"
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
# Then perform the remediations for the watch rules
fix_audit_watch_rule "auditctl" "/sbin/insmod" "x" "modules"
fix_audit_watch_rule "auditctl" "/sbin/rmmod" "x" "modules"
fix_audit_watch_rule "auditctl" "/sbin/modprobe" "x" "modules"
|
Make the auditd Configuration ImmutableruleAdd the following to /etc/audit/audit.rules in order
to make the configuration immutable:
-e 2
With this setting, a reboot will be required to change any
audit rules. identifiers:
CCE-26612-2 references:
AC-6, AU-1(b), AU-2(a), AU-2(c), AU-2(d), IR-5 Remediation script:
readonly AUDIT_RULES='/etc/audit/audit.rules'
# If '-e .*' setting present in audit.rules already, delete it since the
# auditctl(8) manual page instructs it should be the last rule in configuration
sed -i '/-e[[:space:]]\+.*/d' $AUDIT_RULES
# Append '-e 2' requirement at the end of audit.rules
echo '' >> $AUDIT_RULES
echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_RULES
echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_RULES
echo '-e 2' >> $AUDIT_RULES
|
Servicesgroup
The best protection against vulnerable software is running less software. This section describes how to review
the software which Red Hat Enterprise Linux 6 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default Red Hat Enterprise Linux 6 system and provides guidance about which
ones can be safely disabled.
Red Hat Enterprise Linux 6 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building Red Hat Enterprise Linux 6 servers, it is highly recommended to select the minimal packages and then build up
the system from there.
|
contains 124 rules |
Obsolete ServicesgroupThis section discusses a number of network-visible
services which have historically caused problems for system
security, and for which disabling or severely limiting the service
has been the best available guidance for some time. As a result of
this, many of these services are not installed as part of Red Hat Enterprise Linux 6
by default.
Organizations which are running these services should
switch to more secure equivalents as soon as possible.
If it remains absolutely necessary to run one of
these services for legacy reasons, care should be taken to restrict
the service as much as possible, for instance by configuring host
firewall software such as iptables to restrict access to the
vulnerable service to only those remote hosts which have a known
need to use it. |
contains 12 rules |
XinetdgroupThe xinetd service acts as a dedicated listener for some
network services (mostly, obsolete ones) and can be used to provide access
controls and perform some logging. It has been largely obsoleted by other
features, and it is not installed by default. The older Inetd service
is not even available as part of Red Hat Enterprise Linux 6. |
contains 2 rules |
Disable xinetd Servicerule
The xinetd service can be disabled with the following command:
$ sudo chkconfig xinetd off
identifiers:
CCE-27046-2, DISA FSO RHEL-06-000203 references:
CM-7, 305, Test attestation on 20121026 by DS |
Uninstall xinetd PackageruleThe xinetd package can be uninstalled with the following command:
$ sudo yum erase xinetd
identifiers:
CCE-27005-8, DISA FSO RHEL-06-000204 references:
CM-7, 305, Test attestation on 20121026 by DS Remediation script:if rpm -qa | grep -q xinetd; then
yum -y remove xinetd
fi
|
TelnetgroupThe telnet protocol does not provide confidentiality or integrity
for information transmitted on the network. This includes authentication
information such as passwords. Organizations which use telnet should be
actively working to migrate to a more secure protocol. |
contains 2 rules |
Disable telnet Servicerule
The telnet service can be disabled with the following command:
$ sudo chkconfig telnet off
identifiers:
CCE-26836-7, DISA FSO RHEL-06-000211 references:
CM-7, IA-5(1)(c), 68, 1436, 197, 877, 888, Test attestation on 20121026 by DS |
Uninstall telnet-server PackageruleThe telnet-server package can be uninstalled with
the following command:
$ sudo yum erase telnet-server identifiers:
CCE-27073-6, DISA FSO RHEL-06-000206 references:
CM-7, 305, 381, Test attestation on 20121026 by DS Remediation script:if rpm -qa | grep -q telnet-server; then
yum -y remove telnet-server
fi
|
Rlogin, Rsh, and RexecgroupThe Berkeley r-commands are legacy services which
allow cleartext remote access and have an insecure trust
model. |
contains 3 rules |
Uninstall rsh-server PackageruleThe rsh-server package can be uninstalled with
the following command:
$ sudo yum erase rsh-server
identifiers:
CCE-27062-9, DISA FSO RHEL-06-000213 references:
CM-7, 305, 381, Test attestation on 20121026 by DS Remediation script:yum -y erase rsh-server
|
Disable rsh ServiceruleThe rsh service, which is available with
the rsh-server package and runs as a service through xinetd,
should be disabled.
The rsh service can be disabled with the following command:
$ sudo chkconfig rsh off
identifiers:
CCE-26994-4, DISA FSO RHEL-06-000214 references:
CM-7, IA-5(1)(c), 68, 1436, Test attestation on 20121026 by DS |
Remove Rsh Trust FilesruleThe files /etc/hosts.equiv and ~/.rhosts (in
each user's home directory) list remote hosts and users that are trusted by the
local system when using the rshd daemon.
To remove these files, run the following command to delete them from any
location:
$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts
identifiers:
CCE-27270-8, DISA FSO RHEL-06-000019 references:
CM-7, 1436, Test attestation on 20121026 by DS Remediation script:find -type f -name .rhosts -exec rm -f '{}' \;
rm /etc/hosts.equiv
|
NISgroupThe Network Information Service (NIS), also known as 'Yellow
Pages' (YP), and its successor NIS+ have been made obsolete by
Kerberos, LDAP, and other modern centralized authentication
services. NIS should not be used because it suffers from security
problems inherent in its design, such as inadequate protection of
important authentication information. |
contains 2 rules |
Uninstall ypserv PackageruleThe ypserv package can be uninstalled with
the following command:
$ sudo yum erase ypserv
identifiers:
CCE-27079-3, DISA FSO RHEL-06-000220 references:
CM-7, 305, 381, Test attestation on 20121026 by DS Remediation script:if rpm -qa | grep -q ypserv; then
yum -y remove ypserv
fi
|
Disable ypbind ServiceruleThe ypbind service, which allows the system to act as a client in
a NIS or NIS+ domain, should be disabled.
The ypbind service can be disabled with the following command:
$ sudo chkconfig ypbind off
identifiers:
CCE-26894-6, DISA FSO RHEL-06-000221 references:
CM-7, 305, Test attestation on 20121026 by DS |
TFTP Servergroup
TFTP is a lightweight version of the FTP protocol which has
traditionally been used to configure networking equipment. However,
TFTP provides little security, and modern versions of networking
operating systems frequently support configuration via SSH or other
more secure protocols. A TFTP server should be run only if no more
secure method of supporting existing equipment can be
found. |
contains 3 rules |
Disable tftp ServiceruleThe tftp service should be disabled.
The tftp service can be disabled with the following command:
$ sudo chkconfig tftp off
identifiers:
CCE-27055-3, DISA FSO RHEL-06-000223 references:
CM-7, 1436, Test attestation on 20121026 by DS Remediation script:#
# Disable tftp for all run levels
#
/sbin/chkconfig --level 0123456 tftp off
#
# Stop tftp if currently running
#
/sbin/service tftp stop
|
Uninstall tftp-server Packagerule
The tftp-server package can be removed with the following command:
$ sudo yum erase tftp-server
identifiers:
CCE-26946-4, DISA FSO RHEL-06-000222 references:
CM-7, 305, Test attestation on 20121026 by DS |
Ensure tftp Daemon Uses Secure ModeruleIf running the tftp service is necessary, it should be configured
to change its root directory at startup. To do so, ensure
/etc/xinetd.d/tftp includes -s as a command line argument, as shown in
the following example (which is also the default):
server_args = -s /var/lib/tftpboot
identifiers:
CCE-27272-4, DISA FSO RHEL-06-000338 references:
CM-7, 366 |
Base ServicesgroupThis section addresses the base services that are installed on a
Red Hat Enterprise Linux 6 default installation which are not covered in other
sections. Some of these services listen on the network and
should be treated with particular discretion. Other services are local
system utilities that may or may not be extraneous. In general, system services
should be disabled if not required. |
contains 22 rules |
Disable Automatic Bug Reporting Tool (abrtd)ruleThe Automatic Bug Reporting Tool (abrtd) daemon collects
and reports crash data when an application crash is detected. Using a variety
of plugins, abrtd can email crash reports to system administrators, log crash
reports to files, or forward crash reports to a centralized issue tracking
system such as RHTSupport.
The abrtd service can be disabled with the following command:
$ sudo chkconfig abrtd off
identifiers:
CCE-27247-6, DISA FSO RHEL-06-000261 references:
CM-7, 381 Remediation script:#
# Disable abrtd for all run levels
#
/sbin/chkconfig --level 0123456 abrtd off
#
# Stop abrtd if currently running
#
/sbin/service abrtd stop
|
Disable Advanced Configuration and Power Interface (acpid)ruleThe Advanced Configuration and Power Interface Daemon (acpid)
dispatches ACPI events (such as power/reset button depressed) to userspace
programs.
The acpid service can be disabled with the following command:
$ sudo chkconfig acpid off
identifiers:
CCE-27061-1 references:
CM-7 Remediation script:#
# Disable acpid for all run levels
#
/sbin/chkconfig --level 0123456 acpid off
#
# Stop acpid if currently running
#
/sbin/service acpid stop
|
Disable Certmonger Service (certmonger)ruleCertmonger is a D-Bus based service that attempts to simplify interaction
with certifying authorities on networks which use public-key infrastructure. It is often
combined with Red Hat's IPA (Identity Policy Audit) security information management
solution to aid in the management of certificates.
The certmonger service can be disabled with the following command:
$ sudo chkconfig certmonger off
identifiers:
CCE-27267-4 references:
CM-7 Remediation script:#
# Disable certmonger for all run levels
#
/sbin/chkconfig --level 0123456 certmonger off
#
# Stop certmonger if currently running
#
/sbin/service certmonger stop
|
Disable Control Group Config (cgconfig)ruleControl groups allow an administrator to allocate system resources (such as CPU,
memory, network bandwidth, etc) among a defined group (or groups) of processes executing on
a system. The cgconfig daemon starts at boot and establishes the predefined control groups.
The cgconfig service can be disabled with the following command:
$ sudo chkconfig cgconfig off
identifiers:
CCE-27250-0 references:
CM-7 Remediation script:#
# Disable cgconfig for all run levels
#
/sbin/chkconfig --level 0123456 cgconfig off
#
# Stop cgconfig if currently running
#
/sbin/service cgconfig stop
|
Disable Control Group Rules Engine (cgred)ruleThe cgred service moves tasks into control groups according to
parameters set in the /etc/cgrules.conf configuration file.
The cgred service can be disabled with the following command:
$ sudo chkconfig cgred off
identifiers:
CCE-27252-6 references:
CM-7 Remediation script:#
# Disable cgred for all run levels
#
/sbin/chkconfig --level 0123456 cgred off
#
# Stop cgred if currently running
#
/sbin/service cgred stop
|
Disable CPU Speed (cpuspeed)ruleThe cpuspeed service can adjust the clock speed of supported CPUs based upon
the current processing load thereby conserving power and reducing heat.
The cpuspeed service can be disabled with the following command:
$ sudo chkconfig cpuspeed off
identifiers:
CCE-26973-8 references:
CM-7 Remediation script:#
# Disable cpuspeed for all run levels
#
/sbin/chkconfig --level 0123456 cpuspeed off
#
# Stop cpuspeed if currently running
#
/sbin/service cpuspeed stop
|
Disable Hardware Abstraction Layer Service (haldaemon)ruleThe Hardware Abstraction Layer Daemon (haldaemon) collects
and maintains information about the system's hardware configuration.
This service is required on a workstation
running a desktop environment, and may be necessary on any system which
deals with removable media or devices.
The haldaemon service can be disabled with the following command:
$ sudo chkconfig haldaemon off
identifiers:
CCE-27086-8 references:
CM-7 Remediation script:#
# Disable haldaemon for all run levels
#
/sbin/chkconfig --level 0123456 haldaemon off
#
# Stop haldaemon if currently running
#
/sbin/service haldaemon stop
|
Enable IRQ Balance (irqbalance)ruleThe irqbalance service optimizes the balance between
power savings and performance through distribution of hardware interrupts across
multiple processors.
The irqbalance service can be enabled with the following command:
$ sudo chkconfig --level 2345 irqbalance on
identifiers:
CCE-26990-2 references:
CM-7 Remediation script:#
# Enable irqbalance for all run levels
#
/sbin/chkconfig --level 0123456 irqbalance on
#
# Start irqbalance if not currently running
#
/sbin/service irqbalance start
|
Disable KDump Kernel Crash Analyzer (kdump)ruleThe kdump service provides a kernel crash dump analyzer. It uses the kexec
system call to boot a secondary kernel ("capture" kernel) following a system
crash, which can load information from the crashed kernel for analysis.
The kdump service can be disabled with the following command:
$ sudo chkconfig kdump off
identifiers:
CCE-26850-8 references:
CM-7 Remediation script:#
# Disable kdump for all run levels
#
/sbin/chkconfig --level 0123456 kdump off
#
# Stop kdump if currently running
#
/sbin/service kdump stop
|
Disable Software RAID Monitor (mdmonitor)ruleThe mdmonitor service is used for monitoring a software RAID array; hardware
RAID setups do not use this service.
The mdmonitor service can be disabled with the following command:
$ sudo chkconfig mdmonitor off
identifiers:
CCE-27193-2 references:
CM-7 Remediation script:#
# Disable mdmonitor for all run levels
#
/sbin/chkconfig --level 0123456 mdmonitor off
#
# Stop mdmonitor if currently running
#
/sbin/service mdmonitor stop
|
Disable D-Bus IPC Service (messagebus)ruleD-Bus provides an IPC mechanism used by
a growing list of programs, such as those used for Gnome, Bluetooth, and Avahi.
Due to these dependencies, disabling D-Bus may not be practical for
many systems.
The messagebus service can be disabled with the following command:
$ sudo chkconfig messagebus off
identifiers:
CCE-26913-4 references:
CM-7 Remediation script:#
# Disable messagebus for all run levels
#
/sbin/chkconfig --level 0123456 messagebus off
#
# Stop messagebus if currently running
#
/sbin/service messagebus stop
|
Disable Network Console (netconsole)ruleThe netconsole service is responsible for loading the
netconsole kernel module, which logs kernel printk messages over UDP to a
syslog server. This allows debugging of problems where disk logging fails and
serial consoles are impractical.
The netconsole service can be disabled with the following command:
$ sudo chkconfig netconsole off
identifiers:
CCE-27254-2, DISA FSO RHEL-06-000289 references:
CM-7, 381 Remediation script:#
# Disable netconsole for all run levels
#
/sbin/chkconfig --level 0123456 netconsole off
#
# Stop netconsole if currently running
#
/sbin/service netconsole stop
|
Disable ntpdate Service (ntpdate)ruleThe ntpdate service sets the local hardware clock by polling NTP servers
when the system boots. It synchronizes to the NTP servers listed in
/etc/ntp/step-tickers or /etc/ntp.conf
and then sets the local hardware clock to the newly synchronized
system time.
The ntpdate service can be disabled with the following command:
$ sudo chkconfig ntpdate off
identifiers:
CCE-27256-7, DISA FSO RHEL-06-000265 references:
CM-7, 382, Test attestation on 20121024 by DS |
Disable Odd Job Daemon (oddjobd)ruleThe oddjobd service exists to provide an interface and
access control mechanism through which
specified privileged tasks can run tasks for unprivileged client
applications. Communication with oddjobd through the system message bus.
The oddjobd service can be disabled with the following command:
$ sudo chkconfig oddjobd off
identifiers:
CCE-27257-5, DISA FSO RHEL-06-000266 references:
CM-7, 381, Test attestation on 20121024 by DS Remediation script:#
# Disable oddjobd for all run levels
#
/sbin/chkconfig --level 0123456 oddjobd off
#
# Stop oddjobd if currently running
#
/sbin/service oddjobd stop
|
Disable Portreserve (portreserve)ruleThe portreserve service is a TCP port reservation utility that can
be used to prevent portmap from binding to well known TCP ports that are
required for other services.
The portreserve service can be disabled with the following command:
$ sudo chkconfig portreserve off
identifiers:
CCE-27258-3 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Disable portreserve for all run levels
#
/sbin/chkconfig --level 0123456 portreserve off
#
# Stop portreserve if currently running
#
/sbin/service portreserve stop
|
Disable Apache Qpid (qpidd)ruleThe qpidd service provides high speed, secure,
guaranteed delivery services. It is an implementation of the Advanced Message
Queuing Protocol. By default the qpidd service will bind to port 5672 and
listen for connection attempts.
The qpidd service can be disabled with the following command:
$ sudo chkconfig qpidd off
identifiers:
CCE-26928-2, DISA FSO RHEL-06-000267 references:
CM-7, 382 Remediation script:#
# Disable qpidd for all run levels
#
/sbin/chkconfig --level 0123456 qpidd off
#
# Stop qpidd if currently running
#
/sbin/service qpidd stop
|
Disable Network Router Discovery Daemon (rdisc)ruleThe rdisc service implements the client side of the ICMP
Internet Router Discovery Protocol (IRDP), which allows discovery of routers on
the local subnet. If a router is discovered then the local routing table is
updated with a corresponding default route. By default this daemon is disabled.
The rdisc service can be disabled with the following command:
$ sudo chkconfig rdisc off
identifiers:
CCE-27261-7, DISA FSO RHEL-06-000268 references:
AC-4, CM-7, 382, Test attestation on 20121024 by DS Remediation script:#
# Disable rdisc for all run levels
#
/sbin/chkconfig --level 0123456 rdisc off
#
# Stop rdisc if currently running
#
/sbin/service rdisc stop
|
Disable Red Hat Network Service (rhnsd)ruleThe Red Hat Network service automatically queries Red Hat Network
servers to determine whether there are any actions that should be executed,
such as package updates. This only occurs if the system was registered to an
RHN server or satellite and managed as such.
The rhnsd service can be disabled with the following command:
$ sudo chkconfig rhnsd off
identifiers:
CCE-26846-6, DISA FSO RHEL-06-000009 references:
CM-7, 382, Test attestation on 20121024 by DS Remediation script:#
# Disable rhnsd for all run levels
#
/sbin/chkconfig --level 0123456 rhnsd off
#
# Stop rhnsd if currently running
#
/sbin/service rhnsd stop
|
Disable Red Hat Subscription Manager Daemon (rhsmcertd)ruleThe Red Hat Subscription Manager (rhsmcertd) periodically checks for
changes in the entitlement certificates for a registered system and updates it
accordingly.
The rhsmcertd service can be disabled with the following command:
$ sudo chkconfig rhsmcertd off
identifiers:
CCE-27262-5 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Disable rhsmcertd for all run levels
#
/sbin/chkconfig --level 0123456 rhsmcertd off
#
# Stop rhsmcertd if currently running
#
/sbin/service rhsmcertd stop
|
Disable Cyrus SASL Authentication Daemon (saslauthd)ruleThe saslauthd service handles plaintext authentication requests on
behalf of the SASL library. The service isolates all code requiring superuser
privileges for SASL authentication into a single process, and can also be used
to provide proxy authentication services to clients that do not understand SASL
based authentication.
The saslauthd service can be disabled with the following command:
$ sudo chkconfig saslauthd off
identifiers:
CCE-27263-3 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Disable saslauthd for all run levels
#
/sbin/chkconfig --level 0123456 saslauthd off
#
# Stop saslauthd if currently running
#
/sbin/service saslauthd stop
|
Disable SMART Disk Monitoring Service (smartd)ruleSMART (Self-Monitoring, Analysis, and Reporting Technology) is a
feature of hard drives that allows them to detect symptoms of disk failure and
relay an appropriate warning.
The smartd service can be disabled with the following command:
$ sudo chkconfig smartd off
identifiers:
CCE-26853-2 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Disable smartd for all run levels
#
/sbin/chkconfig --level 0123456 smartd off
#
# Stop smartd if currently running
#
/sbin/service smartd stop
|
Disable System Statistics Reset Service (sysstat)ruleThe sysstat service resets various I/O and CPU
performance statistics to zero in order to begin counting from a fresh state
at boot time.
The sysstat service can be disabled with the following command:
$ sudo chkconfig sysstat off
identifiers:
CCE-27265-8 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Disable sysstat for all run levels
#
/sbin/chkconfig --level 0123456 sysstat off
#
# Stop sysstat if currently running
#
/sbin/service sysstat stop
|
Cron and At DaemonsgroupThe cron and at services are used to allow commands to
be executed at a later time. The cron service is required by almost
all systems to perform necessary maintenance tasks, while at may or
may not be required on a given system. Both daemons should be
configured defensively. |
contains 2 rules |
Enable cron ServiceruleThe crond service is used to execute commands at
preconfigured times. It is required by almost all systems to perform necessary
maintenance tasks, such as notifying root of system activity.
The crond service can be enabled with the following command:
$ sudo chkconfig --level 2345 crond on
identifiers:
CCE-27070-2, DISA FSO RHEL-06-000224 references:
CM-7, Test attestation on 20121024 by DS Remediation script:#
# Enable crond for all run levels
#
/sbin/chkconfig --level 0123456 crond on
#
# Start crond if not currently running
#
/sbin/service crond start
|
Disable At Service (atd)ruleThe at and batch commands can be used to
schedule tasks that are meant to be executed only once. This allows delayed
execution in a manner similar to cron, except that it is not
recurring. The daemon atd keeps track of tasks scheduled via
at and batch, and executes them at the specified time.
The atd service can be disabled with the following command:
$ sudo chkconfig atd off
identifiers:
CCE-27249-2, DISA FSO RHEL-06-000262 references:
CM-7, 381 Remediation script:#
# Disable atd for all run levels
#
/sbin/chkconfig --level 0123456 atd off
#
# Stop atd if currently running
#
/sbin/service atd stop
|
SSH ServergroupThe SSH protocol is recommended for remote login and
remote file transfer. SSH provides confidentiality and integrity
for data exchanged between two systems, as well as server
authentication, through the use of public key cryptography. The
implementation included with the system is called OpenSSH, and more
detailed documentation is available from its website,
http://www.openssh.org. Its server program is called sshd and
provided by the RPM package openssh-server. |
contains 10 rules |
Configure OpenSSH Server if NecessarygroupIf the system needs to act as an SSH server, then
certain changes should be made to the OpenSSH daemon configuration
file /etc/ssh/sshd_config. The following recommendations can be
applied to this file. See the sshd_config(5) man page for more
detailed information. |
contains 9 rules |
Allow Only SSH Protocol 2ruleOnly SSH protocol version 2 connections should be
permitted. The default setting in
/etc/ssh/sshd_config is correct, and can be
verified by ensuring that the following
line appears:
Protocol 2
identifiers:
CCE-27072-8, DISA FSO RHEL-06-000227 references:
AC-3(10), IA-5(1)(c), 776, 774, 1436, Test attestation on 20121024 by DS Remediation script:grep -qi ^Protocol /etc/ssh/sshd_config && \
sed -i "s/Protocol.*/Protocol 2/gI" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "Protocol 2" >> /etc/ssh/sshd_config
fi
|
Limit Users' SSH AccessruleBy default, the SSH configuration allows any user with an account
to access the system. In order to specify the users that are allowed to login
via SSH and deny all other users, add or correct the following line in the
/etc/ssh/sshd_config file:
DenyUsers USER1 USER2
Where USER1 and USER2 are valid user names.
identifiers:
CCE-27556-0 references:
AC-3, http://iase.disa.mil/stigs/cci/Pages/index.aspx |
Set SSH Client Alive CountruleTo ensure the SSH idle timeout occurs precisely when the ClientAliveCountMax is set,
edit /etc/ssh/sshd_config as
follows:
ClientAliveCountMax 0
identifiers:
CCE-26282-4, DISA FSO RHEL-06-000231 references:
AC-2(5), SA-8, 879, 1133, Test attestation on 20121024 by DS Remediation script:grep -q ^ClientAliveCountMax /etc/ssh/sshd_config && \
sed -i "s/ClientAliveCountMax.*/ClientAliveCountMax 0/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "ClientAliveCountMax 0" >> /etc/ssh/sshd_config
fi
|
Disable SSH Support for .rhosts FilesruleSSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
To ensure this behavior is disabled, add or correct the
following line in /etc/ssh/sshd_config:
IgnoreRhosts yes
identifiers:
CCE-27124-7, DISA FSO RHEL-06-000234 references:
AC-3, 765, 766 Remediation script:grep -q ^IgnoreRhosts /etc/ssh/sshd_config && \
sed -i "s/IgnoreRhosts.*/IgnoreRhosts yes/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "IgnoreRhosts yes" >> /etc/ssh/sshd_config
fi
|
Disable SSH Root LoginruleThe root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line
in /etc/ssh/sshd_config:
PermitRootLogin no
identifiers:
CCE-27100-7, DISA FSO RHEL-06-000237 references:
AC-3, AC-6(2), IA-2(1), 770, Test attestation on 20121024 by DS Remediation script:
SSHD_CONFIG='/etc/ssh/sshd_config'
# Obtain line number of first uncommented case-insensitive occurrence of Match
# block directive (possibly prefixed with whitespace) present in $SSHD_CONFIG
FIRST_MATCH_BLOCK=$(sed -n '/^[[:space:]]*Match[^\n]*/I{=;q}' $SSHD_CONFIG)
# Obtain line number of first uncommented case-insensitive occurence of
# PermitRootLogin directive (possibly prefixed with whitespace) present in
# $SSHD_CONFIG
FIRST_PERMIT_ROOT_LOGIN=$(sed -n '/^[[:space:]]*PermitRootLogin[^\n]*/I{=;q}' $SSHD_CONFIG)
# Case: Match block directive not present in $SSHD_CONFIG
if [ -z "$FIRST_MATCH_BLOCK" ]
then
# Case: PermitRootLogin directive not present in $SSHD_CONFIG yet
if [ -z "$FIRST_PERMIT_ROOT_LOGIN" ]
then
# Append 'PermitRootLogin no' at the end of $SSHD_CONFIG
echo -e "\nPermitRootLogin no" >> $SSHD_CONFIG
# Case: PermitRootLogin directive present in $SSHD_CONFIG already
else
# Replace first uncommented case-insensitive occurrence
# of PermitRootLogin directive
sed -i "$FIRST_PERMIT_ROOT_LOGIN s/^[[:space:]]*PermitRootLogin.*$/PermitRootLogin no/I" $SSHD_CONFIG
fi
# Case: Match block directive present in $SSHD_CONFIG
else
# Case: PermitRootLogin directive not present in $SSHD_CONFIG yet
if [ -z "$FIRST_PERMIT_ROOT_LOGIN" ]
then
# Prepend 'PermitRootLogin no' before first uncommented
# case-insensitive occurrence of Match block directive
sed -i "$FIRST_MATCH_BLOCK s/^\([[:space:]]*Match[^\n]*\)/PermitRootLogin no\n\1/I" $SSHD_CONFIG
# Case: PermitRootLogin directive present in $SSHD_CONFIG and placed
# before first Match block directive
elif [ "$FIRST_PERMIT_ROOT_LOGIN" -lt "$FIRST_MATCH_BLOCK" ]
then
# Replace first uncommented case-insensitive occurrence
# of PermitRootLogin directive
sed -i "$FIRST_PERMIT_ROOT_LOGIN s/^[[:space:]]*PermitRootLogin.*$/PermitRootLogin no/I" $SSHD_CONFIG
# Case: PermitRootLogin directive present in $SSHD_CONFIG and placed
# after first Match block directive
else
# Prepend 'PermitRootLogin no' before first uncommented
# case-insensitive occurrence of Match block directive
sed -i "$FIRST_MATCH_BLOCK s/^\([[:space:]]*Match[^\n]*\)/PermitRootLogin no\n\1/I" $SSHD_CONFIG
fi
fi
|
Disable SSH Access via Empty PasswordsruleTo explicitly disallow remote login from accounts with
empty passwords, add or correct the following line in
/etc/ssh/sshd_config:
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.
identifiers:
CCE-26887-0, DISA FSO RHEL-06-000239 references:
AC-3, 765, 766, Test attestation on 20121024 by DS Remediation script:grep -q ^PermitEmptyPasswords /etc/ssh/sshd_config && \
sed -i "s/PermitEmptyPasswords.*/PermitEmptyPasswords no/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "PermitEmptyPasswords no" >> /etc/ssh/sshd_config
fi
|
Enable SSH Warning Bannerrule
To enable the warning banner and ensure it is consistent
across the system, add or correct the following line in /etc/ssh/sshd_config:
Banner /etc/issue
Another section contains information on how to create an
appropriate system-wide warning banner.
identifiers:
CCE-27112-2, DISA FSO RHEL-06-000240 references:
AC-8(a), 48, Test attestation on 20121024 by DS Remediation script:grep -q ^Banner /etc/ssh/sshd_config && \
sed -i "s/Banner.*/Banner \/etc\/issue/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "Banner /etc/issue" >> /etc/ssh/sshd_config
fi
|
Do Not Allow SSH Environment OptionsruleTo ensure users are not able to present
environment options to the SSH daemon, add or correct the following line
in /etc/ssh/sshd_config:
PermitUserEnvironment no
identifiers:
CCE-27201-3, DISA FSO RHEL-06-000241 references:
1414, Test attestation on 20121024 by DS Remediation script:grep -q ^PermitUserEnvironment /etc/ssh/sshd_config && \
sed -i "s/PermitUserEnvironment.*/PermitUserEnvironment no/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "PermitUserEnvironment no" >> /etc/ssh/sshd_config
fi
|
Use Only Approved CiphersruleLimit the ciphers to those algorithms which are FIPS-approved.
Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved ciphers:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
The man page sshd_config(5) contains a list of supported ciphers.
identifiers:
CCE-26555-3, DISA FSO RHEL-06-000243 references:
AC-3, AC-17(2), SI-7, IA-5(1)(c), IA-7, 803, 1144, 1145, 1146, Test attestation on 20121024 by DS Remediation script:grep -q ^Ciphers /etc/ssh/sshd_config && \
sed -i "s/Ciphers.*/Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc" >> /etc/ssh/sshd_config
fi
|
Disable SSH Server If Possible (Unusual)ruleThe SSH server service, sshd, is commonly needed.
However, if it can be disabled, do so.
The sshd service can be disabled with the following command:
$ sudo chkconfig sshd off
This is unusual, as SSH is a common method for encrypted and authenticated
remote access.
identifiers:
CCE-27054-6 references:
Test attestation on 20121024 by DS |
X Window SystemgroupThe X Window System implementation included with the
system is called X.org. |
contains 2 rules |
Disable X WindowsgroupUnless there is a mission-critical reason for the
system to run a graphical user interface, ensure X is not set to start
automatically at boot and remove the X Windows software packages.
There is usually no reason to run X Windows
on a dedicated server machine, as it increases the system's attack surface and consumes
system resources. Administrators of server systems should instead login via
SSH or on the text console. |
contains 2 rules |
Disable X Windows Startup By Setting RunlevelruleSetting the system's runlevel to 3 will prevent automatic startup
of the X server. To do so, ensure the following line in /etc/inittab
features a 3 as shown:
id:3:initdefault:
identifiers:
CCE-27119-7, DISA FSO RHEL-06-000290 references:
AC-3, 366, Test attestation on 20121025 by DS |
Remove the X Windows Package GroupruleRemoving all packages which constitute the X Window System
ensures users or malicious software cannot start X.
To do so, run the following command:
$ sudo yum groupremove "X Window System"
identifiers:
CCE-27198-1, DISA FSO RHEL-06-000291 references:
366, Test attestation on 20121025 by DS |
Avahi ServergroupThe Avahi daemon implements the DNS Service Discovery
and Multicast DNS protocols, which provide service and host
discovery on a network. It allows a system to automatically
identify resources on the network, such as printers or web servers.
This capability is also known as mDNSresponder and is a major part
of Zeroconf networking. |
contains 5 rules |
Disable Avahi Server if PossiblegroupBecause the Avahi daemon service keeps an open network
port, it is subject to network attacks.
Disabling it can reduce the system's vulnerability to such attacks.
|
contains 1 rule |
Disable Avahi Server Softwarerule
The avahi-daemon service can be disabled with the following command:
$ sudo chkconfig avahi-daemon off
identifiers:
CCE-27087-6, DISA FSO RHEL-06-000246 references:
CM-7, 366 |
Configure Avahi if Necessarygroup
If your system requires the Avahi daemon, its configuration can be restricted
to improve security. The Avahi daemon configuration file is
/etc/avahi/avahi-daemon.conf. The following security recommendations
should be applied to this file:
See the avahi-daemon.conf(5) man page, or documentation at
http://www.avahi.org, for more detailed information about the configuration options.
|
contains 4 rules |
Serve Avahi Only via Required Protocolrule
If you are using only IPv4, edit /etc/avahi/avahi-daemon.conf and ensure
the following line exists in the [server] section:
use-ipv6=no
Similarly, if you are using only IPv6, disable IPv4 sockets with the line:
use-ipv4=no
identifiers:
CCE-27590-9 references:
CM-7 |
Check Avahi Responses' TTL Fieldrule
To make Avahi ignore packets unless the TTL field is 255, edit
/etc/avahi/avahi-daemon.conf and ensure the following line
appears in the [server] section:
check-response-ttl=yes
identifiers:
CCE-27340-9 references:
CM-7 |
Prevent Other Programs from Using Avahi's Portrule
To prevent other mDNS stacks from running, edit /etc/avahi/avahi-daemon.conf
and ensure the following line appears in the [server] section:
disallow-other-stacks=yes
identifiers:
CCE-27308-6 references:
CM-7 |
Disable Avahi Publishingrule
To prevent Avahi from publishing its records, edit /etc/avahi/avahi-daemon.conf
and ensure the following line appears in the [publish] section:
disable-publishing=yes
identifiers:
CCE-27526-3 references:
CM-7 |
Print SupportgroupThe Common Unix Printing System (CUPS) service provides both local
and network printing support. A system running the CUPS service can accept
print jobs from other systems, process them, and send them to the appropriate
printer. It also provides an interface for remote administration through a web
browser. The CUPS service is installed and activated by default. The project
homepage and more detailed documentation are available at http://www.cups.org.
|
contains 2 rules |
Configure the CUPS Service if NecessarygroupCUPS provides the ability to easily share local printers with
other machines over the network. It does this by allowing machines to share
lists of available printers. Additionally, each machine that runs the CUPS
service can potentially act as a print server. Whenever possible, the printer
sharing and print server capabilities of CUPS should be limited or disabled.
The following recommendations should demonstrate how to do just that.
|
contains 1 rule |
Disable Printer Browsing Entirely if PossibleruleBy default, CUPS listens on the network for printer list
broadcasts on UDP port 631. This functionality is called printer browsing.
To disable printer browsing entirely, edit the CUPS configuration
file, located at /etc/cups/cupsd.conf, to include the following:
Browsing Off
identifiers:
CCE-27108-0 references:
CM-7 |
Disable the CUPS Servicerule
The cups service can be disabled with the following command:
$ sudo chkconfig cups off
identifiers:
CCE-26899-5 references:
CM-7 Remediation script:#
# Disable cups for all run levels
#
/sbin/chkconfig --level 0123456 cups off
#
# Stop cups if currently running
#
/sbin/service cups stop
|
DHCPgroupThe Dynamic Host Configuration Protocol (DHCP) allows
systems to request and obtain an IP address and other configuration
parameters from a server.
This guide recommends configuring networking on clients by manually editing
the appropriate files under /etc/sysconfig. Use of DHCP can make client
systems vulnerable to compromise by rogue DHCP servers, and should be avoided
unless necessary. If using DHCP is necessary, however, there are best practices
that should be followed to minimize security risk.
|
contains 6 rules |
Disable DHCP ServergroupIf the system must act as a DHCP server, the configuration
information it serves should be minimized. Also, support for other protocols
and DNS-updating schemes should be explicitly disabled unless needed. The
configuration file for dhcpd is called /etc/dhcp/dhcpd.conf. The file
begins with a number of global configuration options. The remainder of the file
is divided into sections, one for each block of addresses offered by dhcpd,
each of which contains configuration options specific to that address
block. |
contains 5 rules |
Do Not Use Dynamic DNSruleTo prevent the DHCP server from receiving DNS information from
clients, edit /etc/dhcp/dhcpd.conf, and add or correct the following global
option: ddns-update-style none;
identifiers:
CCE-27049-6 references:
CM-7 |
Deny Decline MessagesruleEdit /etc/dhcp/dhcpd.conf and add or correct the following
global option to prevent the DHCP server from responding the DHCPDECLINE
messages, if possible: deny declines; identifiers:
CCE-27106-4 references:
CM-7 |
Deny BOOTP QueriesruleUnless your network needs to support older BOOTP clients, disable
support for the bootp protocol by adding or correcting the global option:
deny bootp;
identifiers:
CCE-27077-7 references:
CM-7 |
Minimize Served InformationruleEdit /etc/dhcp/dhcpd.conf. Examine each address range section within
the file, and ensure that the following options are not defined unless there is
an operational need to provide this information via DHCP:
option domain-name
option domain-name-servers
option nis-domain
option nis-servers
option ntp-servers
option routers
option time-offset
references:
CM-7 |
Configure LoggingruleEnsure that the following line exists in
/etc/rsyslog.conf:
daemon.* /var/log/daemon.log
Configure logwatch or other log monitoring tools to summarize error conditions
reported by the dhcpd process. identifiers:
CCE-26898-7 references:
AU-12 |
Disable DHCP Clientgroup
DHCP is the default network configuration method provided by the system
installer, and common on many networks. Nevertheless, manual management
of IP addresses for systems implies a greater degree of management and
accountability for network activity.
|
contains 1 rule |
Disable DHCP Clientrule
For each interface on the system (e.g. eth0), edit
/etc/sysconfig/network-scripts/ifcfg-interface and make the
following changes:
Correct the BOOTPROTO line to read:
BOOTPROTO=none
Add or correct the following lines, substituting the appropriate
values based on your site's addressing scheme:
NETMASK=255.255.255.0
IPADDR=192.168.1.2
GATEWAY=192.168.1.1
identifiers:
CCE-27021-5, DISA FSO RHEL-06-000292 references:
CM-7, 366, Test attestation on 20121024 by DS |
Network Time ProtocolgroupThe Network Time Protocol is used to manage the system
clock over a network. Computer clocks are not very accurate, so
time will drift unpredictably on unmanaged systems. Central time
protocols can be used both to ensure that time is consistent among
a network of machines, and that their time is consistent with the
outside world.
If every system on a network reliably reports the same time, then it is much
easier to correlate log messages in case of an attack. In addition, a number of
cryptographic protocols (such as Kerberos) use timestamps to prevent certain
types of attacks. If your network does not have synchronized time, these
protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as
important as local synchronization, or not very important at all. If your
network is connected to the Internet, using a
public timeserver (or one provided by your enterprise) provides globally
accurate timestamps which may be essential in investigating or responding to
an attack which originated outside of your network.
A typical network setup involves a small number of internal systems operating as NTP
servers, and the remainder obtaining time information from those
internal servers.
More information on how to configure the NTP server software,
including configuration of cryptographic authentication for
time data, is available at http://www.ntp.org.
|
contains 2 rules |
Enable the NTP Daemonrule
The ntpd service can be enabled with the following command:
$ sudo chkconfig --level 2345 ntpd on
identifiers:
CCE-27093-4, DISA FSO RHEL-06-000247 references:
AU-8(1), 160, Test attestation on 20121024 by DS Remediation script:#
# Enable ntpd for all run levels
#
/sbin/chkconfig --level 0123456 ntpd on
#
# Start ntpd if not currently running
#
/sbin/service ntpd start
|
Specify a Remote NTP ServerruleTo specify a remote NTP server for time synchronization, edit
the file /etc/ntp.conf. Add or correct the following lines,
substituting the IP or hostname of a remote NTP server for ntpserver:
server ntpserver
This instructs the NTP software to contact that remote server to obtain time
data.
identifiers:
CCE-27098-3, DISA FSO RHEL-06-000248 references:
AU-8(1), 160, Test attestation on 20121024 by DS |
Mail Server Softwaregroup
Mail servers are used to send and receive email over the network.
Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious
targets of network attack.
Ensure that machines are not running MTAs unnecessarily,
and configure needed MTAs as defensively as possible.
Very few systems at any site should be configured to directly receive email over the
network. Users should instead use mail client programs to retrieve email
from a central server that supports protocols such as IMAP or POP3.
However, it is normal for most systems to be independently capable of sending email,
for instance so that cron jobs can report output to an administrator.
Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from
the local system to a central site MTA (or directly delivered to a local account),
but the system still cannot receive mail directly over a network.
The alternatives program in Red Hat Enterprise Linux permits selection of other mail server software
(such as Sendmail), but Postfix is the default and is preferred.
Postfix was coded with security in mind and can also be more effectively contained by
SELinux as its modular design has resulted in separate processes performing specific actions.
More information is available on its website, http://www.postfix.org.
|
contains 2 rules |
Enable Postfix ServiceruleThe Postfix mail transfer agent is used for local mail delivery
within the system. The default configuration only listens for connections to
the default SMTP port (port 25) on the loopback interface (127.0.0.1). It is
recommended to leave this service enabled for local mail delivery.
The postfix service can be enabled with the following command:
$ sudo chkconfig --level 2345 postfix on
identifiers:
CCE-26325-1, DISA FSO RHEL-06-000287 references:
Test attestation on 20121024 by DS Remediation script:#
# Enable postfix for all run levels
#
/sbin/chkconfig --level 0123456 postfix on
#
# Start postfix if not currently running
#
/sbin/service postfix start
|
Uninstall Sendmail PackageruleSendmail is not the default mail transfer agent and is
not installed by default.
The sendmail package can be removed with the following command:
$ sudo yum erase sendmail
identifiers:
CCE-27515-6, DISA FSO RHEL-06-000288 references:
CM-7, Test attestation on 20121024 by DS |
LDAPgroupLDAP is a popular directory service, that is, a
standardized way of looking up information from a central database.
Red Hat Enterprise Linux 6 includes software that enables a system to act as both
an LDAP client and server.
|
contains 1 rule |
Configure OpenLDAP ClientsgroupThis section provides information on which security settings are
important to configure in OpenLDAP clients by manually editing the appropriate
configuration files. Red Hat Enterprise Linux 6 provides an automated configuration tool called
authconfig and a graphical wrapper for authconfig called
system-config-authentication. However, these tools do not provide as
much control over configuration as manual editing of configuration files. The
authconfig tools do not allow you to specify locations of SSL certificate
files, which is useful when trying to use SSL cleanly across several protocols.
Installation and configuration of OpenLDAP on Red Hat Enterprise Linux 6 is available at
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-Directory_Servers.html.
|
contains 1 rule |
Configure LDAP Client to Use TLS For All TransactionsruleConfigure LDAP to enforce TLS use. First, edit the file
/etc/pam_ldap.conf, and add or correct the following lines:
ssl start_tls
Then review the LDAP server and ensure TLS has been configured.
identifiers:
CCE-26690-8, DISA FSO RHEL-06-000252 references:
CM-7, 776, 778, 1453, Test attestation on 20121024 by DS |
NFS and RPCgroupThe Network File System is a popular distributed filesystem for
the Unix environment, and is very widely deployed. This section discusses the
circumstances under which it is possible to disable NFS and its dependencies,
and then details steps which should be taken to secure
NFS's configuration. This section is relevant to machines operating as NFS
clients, as well as to those operating as NFS servers.
|
contains 16 rules |
Disable All NFS Services if PossiblegroupIf there is not a reason for the system to operate as either an
NFS client or an NFS server, follow all instructions in this section to disable
subsystems required by NFS.
|
contains 4 rules |
Disable Services Used Only by NFSgroupIf NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd.
All of these daemons run with elevated privileges, and many listen for network
connections. If they are not needed, they should be disabled to improve system
security posture. |
contains 3 rules |
Disable Network File System Lock Service (nfslock)ruleThe Network File System Lock (nfslock) service starts the required
remote procedure call (RPC) processes which allow clients to lock files on the
server. If the local machine is not configured to mount NFS filesystems then
this service should be disabled.
The nfslock service can be disabled with the following command:
$ sudo chkconfig nfslock off
identifiers:
CCE-27104-9 Remediation script:#
# Disable nfslock for all run levels
#
/sbin/chkconfig --level 0123456 nfslock off
#
# Stop nfslock if currently running
#
/sbin/service nfslock stop
|
Disable Secure RPC Client Service (rpcgssd)rule
The rpcgssd service manages RPCSEC GSS contexts required to secure protocols
that use RPC (most often Kerberos and NFS). The rpcgssd service is the
client-side of RPCSEC GSS. If the system does not require secure RPC then this
service should be disabled.
The rpcgssd service can be disabled with the following command:
$ sudo chkconfig rpcgssd off
identifiers:
CCE-26864-9 Remediation script:#
# Disable rpcgssd for all run levels
#
/sbin/chkconfig --level 0123456 rpcgssd off
#
# Stop rpcgssd if currently running
#
/sbin/service rpcgssd stop
|
Disable RPC ID Mapping Service (rpcidmapd)ruleThe rpcidmapd service is used to map user names and groups to UID
and GID numbers on NFSv4 mounts. If NFS is not in use on the local system then
this service should be disabled.
The rpcidmapd service can be disabled with the following command:
$ sudo chkconfig rpcidmapd off
identifiers:
CCE-26870-6 Remediation script:#
# Disable rpcidmapd for all run levels
#
/sbin/chkconfig --level 0123456 rpcidmapd off
#
# Stop rpcidmapd if currently running
#
/sbin/service rpcidmapd stop
|
Disable netfs if PossiblegroupTo determine if any network filesystems handled by netfs are
currently mounted on the system execute the following command:
$ mount -t nfs,nfs4,smbfs,cifs,ncpfs
If the command did not return any output then disable netfs.
|
contains 1 rule |
Disable Network File Systems (netfs)ruleThe netfs script manages the boot-time mounting of several types
of networked filesystems, of which NFS and Samba are the most common. If these
filesystem types are not in use, the script can be disabled, protecting the
system somewhat against accidental or malicious changes to /etc/fstab
and against flaws in the netfs script itself.
The netfs service can be disabled with the following command:
$ sudo chkconfig netfs off
identifiers:
CCE-27137-9 Remediation script:#
# Disable netfs for all run levels
#
/sbin/chkconfig --level 0123456 netfs off
#
# Stop netfs if currently running
#
/sbin/service netfs stop
|
Configure All Machines which Use NFSgroupThe steps in this section are appropriate for all machines which
run NFS, whether they operate as clients or as servers. |
contains 4 rules |
Configure NFS Services to Use Fixed Ports (NFSv3 and NFSv2)groupFirewalling should be done at each host and at the border
firewalls to protect the NFS daemons from remote access, since NFS servers
should never be accessible from outside the organization. However, by default
for NFSv3 and NFSv2, the RPC Bind service assigns each NFS service to a port
dynamically at service startup time. Dynamic ports cannot be protected by port
filtering firewalls such as iptables.
Therefore, restrict each service to always use a given port, so that
firewalling can be done effectively. Note that, because of the way RPC is
implemented, it is not possible to disable the RPC Bind service even if ports
are assigned statically to all RPC services.
In NFSv4, the mounting and locking protocols have been incorporated into the
protocol, and the server listens on the the well-known TCP port 2049. As such,
NFSv4 does not need to interact with the rpcbind, lockd, and rpc.statd
daemons, which can and should be disabled in a pure NFSv4 environment. The
rpc.mountd daemon is still required on the NFS server to setup
exports, but is not involved in any over-the-wire operations.
|
contains 4 rules |
Configure lockd to use static TCP portruleConfigure the lockd daemon to use a static TCP port as
opposed to letting the RPC Bind service dynamically assign a port. Edit the
file /etc/sysconfig/nfs. Add or correct the following line:
LOCKD_TCPPORT=lockd-port
Where lockd-port is a port which is not used by any other service on
your network.
identifiers:
CCE-27149-4 |
Configure lockd to use static UDP portruleConfigure the lockd daemon to use a static UDP port as
opposed to letting the RPC Bind service dynamically assign a port. Edit the
file /etc/sysconfig/nfs. Add or correct the following line:
LOCKD_UDPPORT=lockd-port
Where lockd-port is a port which is not used by any other service on
your network.
identifiers:
CCE-27063-7 |
Configure statd to use static portruleConfigure the statd daemon to use a static port as
opposed to letting the RPC Bind service dynamically assign a port. Edit the
file /etc/sysconfig/nfs. Add or correct the following line:
STATD_PORT=statd-port
Where statd-port is a port which is not used by any other service on your network.
identifiers:
CCE-26889-6 |
Configure mountd to use static portruleConfigure the mountd daemon to use a static port as
opposed to letting the RPC Bind service dynamically assign a port. Edit the
file /etc/sysconfig/nfs. Add or correct the following line:
MOUNTD_PORT=statd-port
Where mountd-port is a port which is not used by any other service on your network.
identifiers:
CCE-27114-8 |
Configure NFS ClientsgroupThe steps in this section are appropriate for machines which operate as NFS clients. |
contains 5 rules |
Disable NFS Server Daemonsgroup
There is no need to run the NFS server daemons nfs and
rpcsvcgssd except on a small number of properly secured machines
designated as NFS servers. Ensure that these daemons are turned off on
clients. |
contains 3 rules |
Specify UID and GID for Anonymous NFS ConnectionsruleTo specify the UID and GID for remote root users, edit the /etc/exports file and add the following for each export:
anonuid=value greater than UID_MAX from /etc/login.defs
anongid=value greater than GID_MAX from /etc/login.defs
Note that a value of "-1" is technically acceptable as this will randomize the anonuid and
anongid values on a Red Hat Enterprise Linux 6 based NFS server. While acceptable from a security perspective,
a value of -1 may cause interoperability issues, particularly with Red Hat Enterprise Linux 7 client systems.
identifiers:
CCE-27414-2 |
Disable Network File System (nfs)ruleThe Network File System (NFS) service allows remote hosts to mount
and interact with shared filesystems on the local machine. If the local machine
is not designated as a NFS server then this service should be disabled.
The nfs service can be disabled with the following command:
$ sudo chkconfig nfs off
identifiers:
CCE-27199-9 references:
Test attestation on 20121025 by DS Remediation script:#
# Disable nfs for all run levels
#
/sbin/chkconfig --level 0123456 nfs off
#
# Stop nfs if currently running
#
/sbin/service nfs stop
|
Disable Secure RPC Server Service (rpcsvcgssd)ruleThe rpcsvcgssd service manages RPCSEC GSS contexts required to
secure protocols that use RPC (most often Kerberos and NFS). The rpcsvcgssd
service is the server-side of RPCSEC GSS. If the system does not require secure
RPC then this service should be disabled.
The rpcsvcgssd service can be disabled with the following command:
$ sudo chkconfig rpcsvcgssd off
identifiers:
CCE-27122-1 references:
Test attestation on 20121025 by DS Remediation script:#
# Disable rpcsvcgssd for all run levels
#
/sbin/chkconfig --level 0123456 rpcsvcgssd off
#
# Stop rpcsvcgssd if currently running
#
/sbin/service rpcsvcgssd stop
|
Mount Remote Filesystems with Restrictive OptionsgroupEdit the file /etc/fstab. For each filesystem whose type
(column 3) is nfs or nfs4, add the text
,nodev,nosuid to the list of mount options in column 4. If
appropriate, also add ,noexec.
See the section titled "Restrict Partition Mount Options" for a description of
the effects of these options. In general, execution of files mounted via NFS
should be considered risky because of the possibility that an adversary could
intercept the request and substitute a malicious file. Allowing setuid files to
be executed from remote servers is particularly risky, both for this reason and
because it requires the clients to extend root-level trust to the NFS
server. |
contains 2 rules |
Mount Remote Filesystems with nodevrule
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
any NFS mounts.
identifiers:
CCE-27090-0, DISA FSO RHEL-06-000269 references:
CM-7, MP-2, Test attestation on 20121025 by DS |
Mount Remote Filesystems with nosuidrule
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
any NFS mounts.
identifiers:
CCE-26972-0, DISA FSO RHEL-06-000270 references:
Test attestation on 20121025 by DS |
Configure NFS ServersgroupThe steps in this section are appropriate for machines which operate as NFS servers. |
contains 3 rules |
Use Root-Squashing on All ExportsruleIf a filesystem is exported using root squashing, requests from root on the client
are considered to be unprivileged (mapped to a user such as nobody). This provides some mild
protection against remote abuse of an NFS server. Root squashing is enabled by default, and
should not be disabled.
Ensure that no line in /etc/exports contains the option no_root_squash.
identifiers:
CCE-27138-7 |
Restrict NFS Clients to Privileged PortsruleBy default, the server NFS implementation requires that all client requests be made
from ports less than 1024. If your organization has control over machines connected to its
network, and if NFS requests are prohibited at the border firewall, this offers some protection
against malicious requests from unprivileged users. Therefore, the default should not be changed.
To ensure that the default has not been changed, ensure no line in
/etc/exports contains the option insecure.
identifiers:
CCE-27121-3 |
Ensure Insecure File Locking is Not AllowedruleBy default the NFS server requires secure file-lock requests,
which require credentials from the client in order to lock a file. Most NFS
clients send credentials with file lock requests, however, there are a few
clients that do not send credentials when requesting a file-lock, allowing the
client to only be able to lock world-readable files. To get around this, the
insecure_locks option can be used so these clients can access the
desired export. This poses a security risk by potentially allowing the client
access to data for which it does not have authorization.
Remove any instances of the
insecure_locks option from the file /etc/exports.
identifiers:
CCE-27167-6, DISA FSO RHEL-06-000309 references:
764 |
DNS ServergroupMost organizations have an operational need to run at
least one nameserver. However, there are many common attacks
involving DNS server software, and this server software should
be disabled on any system
on which it is not needed. |
contains 3 rules |
Disable DNS Servergroup
DNS software should be disabled on any machine which does not
need to be a nameserver. Note that the BIND DNS server software is
not installed on Red Hat Enterprise Linux 6 by default. The remainder of this section
discusses secure configuration of machines which must be
nameservers.
|
contains 2 rules |
Disable DNS Serverrule
The named service can be disabled with the following command:
$ sudo chkconfig named off
identifiers:
CCE-26873-0 references:
CM-7, 366 |
Uninstall bind PackageruleTo remove the bind package, which contains the
named service, run the following command:
$ sudo yum erase bind
identifiers:
CCE-27030-6 references:
CM-7, 366 |
Protect DNS Data from Tampering or AttackgroupThis section discusses DNS configuration options which make it
more difficult for attackers to gain access to private DNS data or to modify
DNS data. |
contains 1 rule |
Disable Dynamic UpdatesruleIs there a mission-critical reason to enable the risky dynamic
update functionality? If not, edit /etc/named.conf. For each zone
specification, correct the following directive if necessary:
zone "example.com " IN {
allow-update { none; };
...
};
identifiers:
CCE-27105-6 |
FTP ServergroupFTP is a common method for allowing remote access to
files. Like telnet, the FTP protocol is unencrypted, which means
that passwords and other data transmitted during the session can be
captured and that the session is vulnerable to hijacking.
Therefore, running the FTP server software is not recommended.
However, there are some FTP server configurations which may
be appropriate for some environments, particularly those which
allow only read-only anonymous access as a means of downloading
data available to the public. |
contains 4 rules |
Disable vsftpd if Possiblegroup |
contains 2 rules |
Disable vsftpd Servicerule
The vsftpd service can be disabled with the following command:
$ sudo chkconfig vsftpd off
identifiers:
CCE-26948-0 references:
CM-7, 1436 Remediation script:if service vsftpd status >/dev/null; then
service vsftpd stop
fi
|
Uninstall vsftpd Packagerule
The vsftpd package can be removed with the following command:
$ sudo yum erase vsftpd
identifiers:
CCE-26687-4 references:
CM-7, 1436 |
Use vsftpd to Provide FTP Service if NecessarygroupThe primary vsftpd configuration file is
/etc/vsftpd.conf, if that file exists, or
/etc/vsftpd/vsftpd.conf if it does not.
|
contains 2 rules |
Enable Logging of All FTP TransactionsruleAdd or correct the following configuration options within the vsftpd
configuration file, located at /etc/vsftpd/vsftpd.conf:
xferlog_enable=YES
xferlog_std_format=NO
log_ftp_protocol=YES
identifiers:
CCE-27142-9, DISA FSO RHEL-06-000339 |
Create Warning Banners for All FTP UsersruleEdit the vsftpd configuration file, which resides at /etc/vsftpd/vsftpd.conf
by default. Add or correct the following configuration options:
banner_file=/etc/issue
identifiers:
CCE-27145-2, DISA FSO RHEL-06-000348 references:
48 |
Web ServergroupThe web server is responsible for providing access to
content via the HTTP protocol. Web servers represent a significant
security risk because:
The HTTP port is commonly probed by malicious sourcesWeb server software is very complex, and includes a long
history of vulnerabilitiesThe HTTP protocol is unencrypted and vulnerable to passive
monitoring
The system's default web server software is Apache 2 and is
provided in the RPM package httpd. |
contains 22 rules |
Disable Apache if PossiblegroupIf Apache was installed and activated, but the system
does not need to act as a web server, then it should be disabled
and removed from the system.
|
contains 1 rule |
Uninstall httpd Packagerule
The httpd package can be removed with the following command:
$ sudo yum erase httpd
identifiers:
CCE-27133-8 references:
CM-7 Remediation script:if rpm -qa | grep -q httpd; then
yum -y remove httpd
fi
|
Secure Apache ConfigurationgroupThe httpd configuration file is
/etc/httpd/conf/httpd.conf. Apply the recommendations in the remainder
of this section to this file. |
contains 21 rules |
Restrict Web Server Information Leakagegroup
The ServerTokens and ServerSignature directives determine how
much information the web server discloses about the configuration of the
system. |
contains 1 rule |
Set httpd ServerTokens Directive to ProdruleServerTokens Prod restricts information in page headers, returning only the word "Apache."
Add or correct the following directive in /etc/httpd/conf/httpd.conf:
ServerTokens Prod
identifiers:
CCE-27425-8 references:
CM-7 |
Minimize Web Server Loadable Modulesgroup
A default installation of httpd includes a plethora of dynamically shared objects (DSO)
that are loaded at run-time. Unlike the aforementioned compiled-in modules, a DSO can be
disabled in the configuration file by removing the corresponding LoadModule directive.
Note: A DSO only provides additional functionality if associated directives are included
in the httpd configuration file. It should also be noted that removing a DSO will produce
errors on httpd startup if the configuration file contains directives that apply to that
module. Refer to http://httpd.apache.org/docs/ for details on which directives
are associated with each DSO.
Following each DSO removal, the configuration can be tested with the following command
to check if everything still works:
$ sudo service httpd configtest
The purpose of each of the modules loaded by default will now be addressed one at a time.
If none of a module's directives are being used, remove it.
|
contains 12 rules |
httpd Core Modulesgroup
These modules comprise a basic subset of modules that are likely needed for base httpd
functionality; ensure they are not commented out in /etc/httpd/conf/httpd.conf:
LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule authn_default_module modules/mod_authn_default.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_default_module modules/mod_authz_default.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule logio_module modules/mod_logio.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule mime_module modules/mod_mome.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule dir_module modules/mod_dir.so
LoadModule alias_module modules/mod_alias.so
Minimizing the number of loadable modules available to the web server reduces risk
by limiting the capabilities allowed by the web server.
|
contains 12 rules |
Disable HTTP Digest Authenticationrule
The auth_digest module provides encrypted authentication sessions.
If this functionality is unnecessary, comment out the related module:
#LoadModule auth_digest_module modules/mod_auth_digest.so
identifiers:
CCE-27553-7 |
Disable HTTP mod_rewriterule
The mod_rewrite module is very powerful and can protect against
certain classes of web attacks. However, it is also very complex and has a
significant history of vulnerabilities itself. If its functionality is
unnecessary, comment out the related module:
#LoadModule rewrite_module modules/mod_rewrite.so
identifiers:
CCE-27570-1 |
Disable LDAP Supportrule
The ldap module provides HTTP authentication via an LDAP directory.
If its functionality is unnecessary, comment out the related modules:
#LoadModule ldap_module modules/mod_ldap.so
#LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
If LDAP is to be used, SSL encryption should be used as well.
identifiers:
CCE-27395-3 |
Disable Server Side Includesrule
Server Side Includes provide a method of dynamically generating web pages through the
insertion of server-side code. However, the technology is also deprecated and
introduces significant security concerns.
If this functionality is unnecessary, comment out the related module:
#LoadModule include_module modules/mod_include.so
If there is a critical need for Server Side Includes, they should be enabled with the
option IncludesNoExec to prevent arbitrary code execution. Additionally, user
supplied data should be encoded to prevent cross-site scripting vulnerabilities.
identifiers:
CCE-27558-6 |
Disable MIME Magicrule
The mime_magic module provides a second layer of MIME support that in most configurations
is likely extraneous. If its functionality is unnecessary, comment out the related module:
#LoadModule mime_magic_module modules/mod_mime_magic.so
identifiers:
CCE-27541-2 |
Disable WebDAV (Distributed Authoring and Versioning)rule
WebDAV is an extension of the HTTP protocol that provides distributed and
collaborative access to web content. If its functionality is unnecessary,
comment out the related modules:
#LoadModule dav_module modules/mod_dav.so
#LoadModule dav_fs_module modules/mod_dav_fs.so
If there is a critical need for WebDAV, extra care should be taken in its configuration.
Since DAV access allows remote clients to manipulate server files, any location on the
server that is DAV enabled should be protected by access controls.
identifiers:
CCE-27329-2 |
Disable Server Activity Statusrule
The status module provides real-time access to statistics on the internal operation of
the web server. This may constitute an unnecessary information leak and should be disabled
unless necessary. To do so, comment out the related module:
#LoadModule status_module modules/mod_status.so
If there is a critical need for this module, ensure that access to the status
page is properly restricted to a limited set of hosts in the status handler
configuration.
identifiers:
CCE-27468-8 |
Disable Web Server Configuration Displayrule
The info module creates a web page illustrating the configuration of the web server. This
can create an unnecessary security leak and should be disabled.
If its functionality is unnecessary, comment out the module:
#LoadModule info_module modules/mod_info.so
If there is a critical need for this module, use the Location directive to provide
an access control list to restrict access to the information.
identifiers:
CCE-27507-3 |
Disable URL Correction on Misspelled Entriesrule
The speling module attempts to find a document match by allowing one misspelling in an
otherwise failed request. If this functionality is unnecessary, comment out the module:
#LoadModule speling_module modules/mod_speling.so
This functionality weakens server security by making site enumeration easier.
identifiers:
CCE-27276-5 |
Disable Proxy Supportrule
The proxy module provides proxying support, allowing httpd to forward requests and
serve as a gateway for other servers. If its functionality is unnecessary, comment out the module:
#LoadModule proxy_module modules/mod_proxy.so
If proxy support is needed, load mod_proxy and the appropriate proxy protocol handler
module (one of mod_proxy_http, mod_proxy_ftp, or mod_proxy_connect). Additionally,
make certain that a server is secure before enabling proxying, as open proxy servers
are a security risk. mod_proxy_balancer enables load balancing, but requires that
mod status be enabled.
identifiers:
CCE-27442-3 |
Disable Cache Supportrule
The cache module allows httpd to cache data, optimizing access to
frequently accessed content. However, it introduces potential security flaws
such as the possibility of circumventing Allow and
Deny directives.
If this functionality is
unnecessary, comment out the module:
#LoadModule cache_module modules/mod_cache.so
If caching is required, it should not be enabled for any limited-access content.
identifiers:
CCE-26859-9 |
Disable CGI Supportrule
The cgi module allows HTML to interact with the CGI web programming language.
If this functionality is unnecessary, comment out the module:
#LoadModule cgi_module modules/mod_cgi.so
If the web server requires the use of CGI, enable mod_cgi.
identifiers:
CCE-27362-3 |
Directory Restrictionsgroup
The Directory tags in the web server configuration file allow finer grained access
control for a specified directory. All web directories should be configured on a
case-by-case basis, allowing access only where needed.
|
contains 4 rules |
Restrict Root Directoryrule
The httpd root directory should always have the most restrictive configuration enabled.
<Directory / >
Options None
AllowOverride None
Order allow,deny
</Directory>
identifiers:
CCE-27009-0 |
Restrict Web Directoryrule
The default configuration for the web (/var/www/html) Directory allows directory
indexing (Indexes) and the following of symbolic links (FollowSymLinks).
Neither of these is recommended.
The /var/www/html directory hierarchy should not be viewable via the web, and
symlinks should only be followed if the owner of the symlink also owns the linked file.
Ensure that this policy is adhered to by altering the related section of the configuration:
<Directory "/var/www/html">
# ...
Options SymLinksIfOwnerMatch
# ...
</Directory>
identifiers:
CCE-27574-3 |
Restrict Other Critical Directoriesrule
All accessible web directories should be configured with similarly restrictive settings.
The Options directive should be limited to necessary functionality and the AllowOverride
directive should be used only if needed. The Order and Deny access control tags
should be used to deny access by default, allowing access only where necessary.
identifiers:
CCE-27565-1 |
Limit Available Methodsrule
Web server methods are defined in section 9 of RFC 2616 (http://www.ietf.org/rfc/rfc2616.txt).
If a web server does not require the implementation of all available methods,
they should be disabled.
Note: GET and POST are the most common methods. A majority of the others
are limited to the WebDAV protocol.
<Directory /var/www/html>
# ...
# Only allow specific methods (this command is case-sensitive!)
<LimitExcept GET POST>
Order allow,deny
</LimitExcept>
# ...
</Directory>
identifiers:
CCE-27581-8 |
Use Appropriate Modules to Improve httpd's Securitygroup
Among the modules available for httpd are several whose use may improve the
security of the web server installation. This section recommends and discusses
the deployment of security-relevant modules.
|
contains 2 rules |
Deploy mod_sslgroup
Because HTTP is a plain text protocol, all traffic is susceptible to passive
monitoring. If there is a need for confidentiality, SSL should be configured
and enabled to encrypt content.
Note: mod_nss is a FIPS 140-2 certified alternative to mod_ssl.
The modules share a considerable amount of code and should be nearly identical
in functionality. If FIPS 140-2 validation is required, then mod_nss should
be used. If it provides some feature or its greater compatibility is required,
then mod_ssl should be used.
|
contains 1 rule |
Install mod_sslrule
Install the mod_ssl module:
$ sudo yum install mod_ssl
identifiers:
CCE-27403-5 |
Deploy mod_securitygroup
The security module provides an application level firewall for httpd.
Following its installation with the base ruleset, specific configuration advice can be found at
http://www.modsecurity.org/ to design a policy that best matches the security needs of
the web applications. Usage of mod_security is highly recommended for some environments,
but it should be noted this module does not ship with Red Hat Enterprise Linux itself,
and instead is provided via Extra Packages for Enterprise Linux (EPEL).
For more information on EPEL please refer to http://fedoraproject.org/wiki/EPEL.
|
contains 1 rule |
Install mod_securityrule
Install the security module:
$ sudo yum install mod_security
identifiers:
CCE-27525-5 |
Configure Operating System to Protect Web Servergroup
The following configuration steps should be taken on the machine which hosts the
web server, in order to provide as safe an environment as possible for the web server.
|
contains 2 rules |
Restrict File and Directory Accessgroup
Minimize access to critical httpd files and directories.
|
contains 2 rules |
Set Permissions on the /etc/httpd/conf/ Directoryrule
Set permissions on the web server configuration directory to 750:
$ sudo chmod 750 /etc/httpd/conf/
identifiers:
CCE-27487-8 |
Set Permissions on All Configuration Files Inside /etc/httpd/conf/rule
Set permissions on the web server configuration files to 640:
$ sudo chmod 640 /etc/httpd/conf/*
identifiers:
CCE-27316-9 references:
CM-7 |
IMAP and POP3 ServergroupDovecot provides IMAP and POP3 services. It is not
installed by default. The project page at http://www.dovecot.org
contains more detailed information about Dovecot
configuration. |
contains 5 rules |
Disable DovecotgroupIf the system does not need to operate as an IMAP or
POP3 server, the dovecot software should be disabled and removed.
|
contains 2 rules |
Disable Dovecot Servicerule
The dovecot service can be disabled with the following command:
$ sudo chkconfig dovecot off
identifiers:
CCE-26922-5 |
Uninstall dovecot PackageruleThe dovecot package can be uninstalled
with the following command:
$ sudo yum erase dovecot
identifiers:
CCE-27039-7 Remediation script:if rpm -qa | grep -q dovecot; then
yum -y remove dovecot
fi
|
Configure Dovecot if NecessarygroupIf the system will operate as an IMAP or
POP3 server, the dovecot software should be configured securely by following
the recommendations below.
|
contains 3 rules |
Enable SSL SupportgroupSSL should be used to encrypt network traffic between the
Dovecot server and its clients. Users must authenticate to the Dovecot
server in order to read their mail, and passwords should never be
transmitted in clear text. In addition, protecting mail as it is
downloaded is a privacy measure, and clients may use SSL certificates
to authenticate the server, preventing another system from impersonating
the server.
|
contains 3 rules |
Enable the SSL flag in /etc/dovecot.confruleTo allow clients to make encrypted connections the ssl
flag in Dovecot's configuration file needs to be set to yes.
Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following line:
ssl = yes
identifiers:
CCE-27571-9 |
Configure Dovecot to Use the SSL Certificate fileruleThis option tells Dovecot where to find the the mail
server's SSL Certificate.
Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following
line (note: the path below is the default path set by the Dovecot installation. If
you are using a different path, ensure you reference the appropriate file):
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
identifiers:
CCE-27459-7 |
Configure Dovecot to Use the SSL Key fileruleThis option tells Dovecot where to find the the mail
server's SSL Key.
Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following
line (note: the path below is the default path set by the Dovecot installation. If
you are using a different path, ensure you reference the appropriate file):
ssl_key = </etc/pki/dovecot/private/dovecot.pem
identifiers:
CCE-27633-7 |
Samba(SMB) Microsoft Windows File Sharing ServergroupWhen properly configured, the Samba service allows
Linux machines to provide file and print sharing to Microsoft
Windows machines. There are two software packages that provide
Samba support. The first, samba-client, provides a series of
command line tools that enable a client machine to access Samba
shares. The second, simply labeled samba, provides the Samba
service. It is this second package that allows a Linux machine to
act as an Active Directory server, a domain controller, or as a
domain member. Only the samba-client package is installed by
default. |
contains 4 rules |
Disable Samba if Possiblegroup
Even after the Samba server package has been installed, it
will remain disabled. Do not enable this service unless it is
absolutely necessary to provide Microsoft Windows file and print
sharing functionality.
|
contains 1 rule |
Disable Sambarule
The smb service can be disabled with the following command:
$ sudo chkconfig smb off
identifiers:
CCE-27143-7 references:
1436 |
Configure Samba if NecessarygroupAll settings for the Samba daemon can be found in
/etc/samba/smb.conf. Settings are divided between a
[global] configuration section and a series of user
created share definition sections meant to describe file or print
shares on the system. By default, Samba will operate in user mode
and allow client machines to access local home directories and
printers. It is recommended that these settings be changed or that
additional limitations be set in place. |
contains 3 rules |
Disable Root Access to SMB SharesruleAdministrators should not use administrator accounts to access
Samba file and printer shares. Disable the root user and the wheel
administrator group:
[share]
invalid users = root @wheel
If administrator accounts cannot be disabled, ensure that local machine
passwords and Samba service passwords do not match. identifiers:
CCE-27533-9 |
Require Client SMB Packet Signing, if using smbclientrule
To require samba clients running smbclient to use
packet signing, add the following to the [global] section
of the Samba configuration file, /etc/samba/smb.conf:
client signing = mandatory
Requiring samba clients such as smbclient to use packet
signing ensures they can
only communicate with servers that support packet signing.
identifiers:
CCE-26328-5, DISA FSO RHEL-06-000272 Remediation script:######################################################################
#By Luke "Brisk-OH" Brisk
#luke.brisk@boeing.com or luke.brisk@gmail.com
######################################################################
CLIENTSIGNING=$( grep -ic 'client signing' /etc/samba/smb.conf )
if [ "$CLIENTSIGNING" -eq 0 ]; then
# Add to global section
sed -i 's/\[global\]/\[global\]\n\n\tclient signing = mandatory/g' /etc/samba/smb.conf
else
sed -i 's/[[:blank:]]*client[[:blank:]]signing[[:blank:]]*=[[:blank:]]*no/ client signing = mandatory/g' /etc/samba/smb.conf
fi
|
Require Client SMB Packet Signing, if using mount.cifsruleRequire packet signing of clients who mount Samba
shares using the mount.cifs program (e.g., those who specify shares
in /etc/fstab). To do so, ensure signing options (either
sec=krb5i or sec=ntlmv2i) are used.
See the mount.cifs(8) man page for more information. A Samba
client should only communicate with servers who can support SMB
packet signing.
identifiers:
CCE-26792-2, DISA FSO RHEL-06-000273 |
Proxy ServergroupA proxy server is a very desirable target for a
potential adversary because much (or all) sensitive data for a
given infrastructure may flow through it. Therefore, if one is
required, the machine acting as a proxy server should be dedicated
to that purpose alone and be stored in a physically secure
location. The system's default proxy server software is Squid, and
provided in an RPM package of the same name. |
contains 2 rules |
Disable Squid if PossiblegroupIf Squid was installed and activated, but the system
does not need to act as a proxy server, then it should be disabled
and removed.
|
contains 2 rules |
Disable Squidrule
The squid service can be disabled with the following command:
$ sudo chkconfig squid off
identifiers:
CCE-27146-0 |
Uninstall squid Packagerule
The squid package can be removed with the following command:
$ sudo yum erase squid
identifiers:
CCE-26977-9 |
SNMP ServergroupThe Simple Network Management Protocol allows
administrators to monitor the state of network devices, including
computers. Older versions of SNMP were well-known for weak
security, such as plaintext transmission of the community string
(used for authentication) and usage of easily-guessable
choices for the community string. |
contains 2 rules |
Disable SNMP Server if PossiblegroupThe system includes an SNMP daemon that allows for its remote
monitoring, though it not installed by default. If it was installed and
activated but is not needed, the software should be disabled and removed.
|
contains 2 rules |
Disable snmpd Servicerule
The snmpd service can be disabled with the following command:
$ sudo chkconfig snmpd off
identifiers:
CCE-26906-8 |
Uninstall net-snmp PackageruleThe net-snmp package provides the snmpd service.
The net-snmp package can be removed with the following command:
$ sudo yum erase net-snmp
identifiers:
CCE-26332-7 Remediation script:if rpm -qa | grep -q net-snmp; then
yum -y remove net-snmp
fi
|