Introduction
Test Result
Result ID | Profile | Start time | End time | Benchmark | Benchmark version |
xccdf_org.open-scap_testresult_CSCF-RHEL6-MLS | CSCF-RHEL6-MLS | 2014-07-14 14:33 | 2014-07-14 14:34 | embedded | 0.9 |
Target info
Targets
|
Addresses
|
Applicable platforms
|
Score
system | score | max | % | bar |
urn:xccdf:scoring:default | 96.79 | 100.00 | 96.79% |
Results overview
Rule Results Summary
pass | fixed | fail | error | not selected | not checked | not applicable | informational | unknown | total |
192 | 0 | 0 | 0 | 181 | 24 | 0 | 0 | 2 | 399 |
Rule results summary
Results details
Result for Ensure /var/log/audit Located On Separate Partition
Result: pass
Rule ID: partition_for_var_log_audit
Time: 2014-07-14 14:33
Severity: low
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.
Placing /var/log/audit
in its own partition
enables better separation between audit files
and other files, and helps ensure that
auditing cannot be halted due to the partition running out
of space.
Security identifiers
- CCE-26436-6
Result for Install AIDE
Result: pass
Rule ID: package_aide_installed
Time: 2014-07-14 14:33
Severity: medium
Install the AIDE package with the command:
# yum install aide
The AIDE package must be installed if it is to be available for integrity checking.
Security identifiers
- CCE-27024-9
Remediation script
yum -y install aide
Result for Disable Prelinking
Result: pass
Rule ID: disable_prelink
Time: 2014-07-14 14:33
Severity: low
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:
# /usr/sbin/prelink -ua
The prelinking feature can interfere with the operation of AIDE, because it changes binaries.
Security identifiers
- CCE-27221-1
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
Result for Build and Test AIDE Database
Result: notchecked
Rule ID: aide_build_database
Time: 2014-07-14 14:33
Severity: low
Run the following command to generate a new database:
# /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:
# cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
# /usr/sbin/aide --check
If this check produces any unexpected output, investigate.
For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.
Security identifiers
- CCE-27135-3
Result for Configure Periodic Execution of AIDE
Result: notchecked
Rule ID: aide_periodic_cron_checking
Time: 2014-07-14 14:33
Severity: medium
To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab
:
05 4 * * * root /usr/sbin/aide --check
AIDE can be executed periodically through other means; this is merely one example.
By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.
Security identifiers
- CCE-27222-9
Result for Install Intrusion Detection Software
Result: notchecked
Rule ID: install_hids
Time: 2014-07-14 14:33
Severity: high
The base Red Hat platform already includes a sophisticated auditing system that
can detect intruder activity, as well as SELinux, which provides host-based
intrusion prevention capabilities by confining privileged programs and user
sessions which may become compromised.
Host-based intrusion detection tools provide a system-level defense when an intruder gains access to a system or network.
Security identifiers
- CCE-27409-2
Result for Install Virus Scanning Software
Result: notchecked
Rule ID: install_antivirus
Time: 2014-07-14 14:33
Severity: low
Install virus scanning software, which uses signatures to search for the presence of viruses on the filesystem. The McAfee uvscan virus scanning tool is provided for DoD systems. Ensure virus definition files are no older than 7 days, or their last release. Configure the virus scanning software to perform scans dynamically on all accessed files. If this is not possible, configure the system to scan all altered files on the system on a daily basis. If the system processes inbound SMTP mail, configure the virus scanner to scan all received mail.
Virus scanning software can be used to detect if a system has been compromised by computer viruses, as well as to limit their spread to other systems.
Security identifiers
- CCE-27529-7
Result for Add nodev Option to Non-Root Local Partitions
Result: pass
Rule ID: mountopt_nodev_on_nonroot_partitions
Time: 2014-07-14 14:33
Severity: low
The 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 non-root local partitions.
The nodev
mount option prevents files from being
interpreted as character or block devices. The only legitimate location
for device files is the /dev
directory located on the root partition.
The only exception to this is chroot jails, for which it is not advised
to set nodev
on these filesystems.
Security identifiers
- CCE-27045-4
Result for Add nodev Option to /tmp
Result: pass
Rule ID: mount_option_tmp_nodev
Time: 2014-07-14 14:33
Severity: low
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
.
The only legitimate location for device files is the /dev
directory
located on the root partition. The only exception to this is chroot jails.
Security identifiers
- CCE-26499-4
Result for Add noexec Option to /tmp
Result: pass
Rule ID: mount_option_tmp_noexec
Time: 2014-07-14 14:33
Severity: low
The 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
.
Allowing users to execute binaries from world-writable directories
such as /tmp
should never be necessary in normal operation and
can expose the system to potential compromise.
Security identifiers
- CCE-26720-3
Result for Add nosuid Option to /tmp
Result: pass
Rule ID: mount_option_tmp_nosuid
Time: 2014-07-14 14:33
Severity: low
The nosuid
mount option can be used to prevent
execution of setuid programs in /tmp
. The suid/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
.
The presence of suid and sgid executables should be tightly controlled. Users should not be able to execute suid or sgid binaries from temporary storage partitions.
Security identifiers
- CCE-26762-5
Result for Add nodev Option to /dev/shm
Result: pass
Rule ID: mount_option_dev_shm_nodev
Time: 2014-07-14 14:33
Severity: low
The 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
.
The only legitimate location for device files is the /dev
directory
located on the root partition. The only exception to this is chroot jails.
Security identifiers
- CCE-26778-1
Result for Add noexec Option to /dev/shm
Result: pass
Rule ID: mount_option_dev_shm_noexec
Time: 2014-07-14 14:33
Severity: low
The 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
.
Allowing users to execute binaries from world-writable directories
such as /dev/shm
can expose the system to potential compromise.
Security identifiers
- CCE-26622-1
Result for Add nosuid Option to /dev/shm
Result: pass
Rule ID: mount_option_dev_shm_nosuid
Time: 2014-07-14 14:33
Severity: low
The nosuid
mount option can be used to prevent execution
of setuid programs in /dev/shm
. The suid/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
.
The presence of suid and sgid executables should be tightly controlled. Users should not be able to execute suid or sgid binaries from temporary storage partitions.
Security identifiers
- CCE-26486-1
Result for Disable Modprobe Loading of USB Storage Driver
Result: pass
Rule ID: kernel_module_usb-storage_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
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.
USB storage devices such as thumb drives can be used to introduce malicious software.
Security identifiers
- CCE-27016-5
Remediation script
echo "install usb-storage /bin/false" > /etc/modprobe.d/usb-storage.conf
Result for Disable Booting from USB Devices in Boot Firmware
Result: notchecked
Rule ID: bios_disable_usb_boot
Time: 2014-07-14 14:33
Severity: low
Configure the system boot firmware (historically called BIOS on PC systems) to disallow booting from USB drives.
Booting a system from a USB device would allow an attacker to circumvent any security measures provided by the operating system. Attackers could mount partitions and modify the configuration of the OS.
Security identifiers
- CCE-26923-3
Result for Disable the Automounter
Result: pass
Rule ID: service_autofs_disabled
Time: 2014-07-14 14:33
Severity: low
The 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:
# chkconfig autofs off
Disabling the automounter permits the administrator to
statically control filesystem mounting through /etc/fstab
.
Security identifiers
- CCE-26976-1
Remediation script
#
# Disable autofs for all run levels
#
chkconfig --level 0123456 autofs off
#
# Stop autofs if currently running
#
service autofs stop
Result for Disable GNOME Automounting
Result: pass
Rule ID: gconf_gnome_disable_automount
Time: 2014-07-14 14:33
Severity: low
The 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:
# gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/nautilus/preferences/media_automount false
# gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/nautilus/preferences/media_autorun_never true
Disabling automatic mounting in GNOME can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.
Security identifiers
- CCE-27035-5
Result for Disable Mounting of cramfs
Result: pass
Rule ID: kernel_module_cramfs_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26340-0
Remediation script
echo "install cramfs /bin/false" > /etc/modprobe.d/cramfs.conf
Result for Disable Mounting of freevxfs
Result: pass
Rule ID: kernel_module_freevxfs_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26544-7
Remediation script
echo "install freevxfs /bin/false" > /etc/modprobe.d/freevxfs.conf
Result for Disable Mounting of jffs2
Result: pass
Rule ID: kernel_module_jffs2_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26670-0
Remediation script
echo "install jffs2 /bin/false" > /etc/modprobe.d/jffs2.conf
Result for Disable Mounting of hfs
Result: pass
Rule ID: kernel_module_hfs_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26800-3
Remediation script
echo "install hfs /bin/false" > /etc/modprobe.d/hfs.conf
Result for Disable Mounting of hfsplus
Result: pass
Rule ID: kernel_module_hfsplus_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26361-6
Remediation script
echo "install hfsplus /bin/false" > /etc/modprobe.d/hfsplus.conf
Result for Disable Mounting of squashfs
Result: pass
Rule ID: kernel_module_squashfs_disabled
Time: 2014-07-14 14:33
Severity: low
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/false
This effectively prevents usage of this uncommon filesystem.
Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Security identifiers
- CCE-26404-4
Remediation script
echo "install squashfs /bin/false" > /etc/modprobe.d/squashfs.conf
Result for Disable All GNOME Thumbnailers
Result: pass
Rule ID: disable_gnome_thumbnailers
Time: 2014-07-14 14:33
Severity: low
The 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:
# 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.
An attacker with knowledge of a flaw in a GNOME thumbnailer application could craft a malicious file to exploit this flaw. Assuming the attacker could place the malicious file on the local filesystem (via a web upload for example) and assuming a user browses the same location using Nautilus, the malicious file would exploit the thumbnailer with the potential for malicious code execution. It is best to disable these thumbnailer applications unless they are explicitly required.
Security identifiers
- CCE-27224-5
Result for Verify User Who Owns shadow File
Result: pass
Rule ID: userowner_shadow_file
Time: 2014-07-14 14:33
Severity: medium
To properly set the owner of /etc/shadow
, run the command:
# chown root /etc/shadow
The /etc/shadow
file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture.
Security identifiers
- CCE-26947-2
Remediation script
chown root /etc/shadow
Result for Verify Group Who Owns shadow File
Result: pass
Rule ID: groupowner_shadow_file
Time: 2014-07-14 14:33
Severity: medium
To properly set the group owner of /etc/shadow
, run the command:
# chgrp root /etc/shadow
The /etc/shadow
file stores password hashes. Protection of this file is
critical for system security.
Security identifiers
- CCE-26967-0
Remediation script
chgrp root /etc/shadow
Result for Verify Permissions on shadow File
Result: pass
Rule ID: file_permissions_etc_shadow
Time: 2014-07-14 14:33
Severity: medium
To properly set the permissions of /etc/shadow
, run the command:
# chmod 0000 /etc/shadow
The /etc/shadow
file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture.
Security identifiers
- CCE-26992-8
Remediation script
chmod 0000 /etc/shadow
Result for Verify User Who Owns group File
Result: pass
Rule ID: file_owner_etc_group
Time: 2014-07-14 14:33
Severity: medium
To properly set the owner of /etc/group
, run the command:
# chown root /etc/group
The /etc/group
file contains information regarding groups that are configured
on the system. Protection of this file is important for system security.
Security identifiers
- CCE-26822-7
Result for Verify Group Who Owns group File
Result: pass
Rule ID: file_groupowner_etc_group
Time: 2014-07-14 14:33
Severity: medium
To properly set the group owner of /etc/group
, run the command:
# chgrp root /etc/group
The /etc/group
file contains information regarding groups that are configured
on the system. Protection of this file is important for system security.
Security identifiers
- CCE-26930-8
Result for Verify Permissions on group File
Result: pass
Rule ID: file_permissions_etc_group
Time: 2014-07-14 14:33
Severity: medium
To properly set the permissions of /etc/group
, run the command:
# chmod 644 /etc/group
The /etc/group
file contains information regarding groups that are configured
on the system. Protection of this file is important for system security.
Security identifiers
- CCE-26954-8
Result for Verify User Who Owns gshadow File
Result: pass
Rule ID: file_owner_etc_gshadow
Time: 2014-07-14 14:33
Severity: medium
To properly set the owner of /etc/gshadow
, run the command:
# chown root /etc/gshadow
The /etc/gshadow
file contains group password hashes. Protection of this file
is critical for system security.
Security identifiers
- CCE-27026-4
Result for Verify Group Who Owns gshadow File
Result: pass
Rule ID: file_groupowner_etc_gshadow
Time: 2014-07-14 14:33
Severity: medium
To properly set the group owner of /etc/gshadow
, run the command:
# chgrp root /etc/gshadow
The /etc/gshadow
file contains group password hashes. Protection of this file
is critical for system security.
Security identifiers
- CCE-26975-3
Result for Verify Permissions on gshadow File
Result: pass
Rule ID: file_permissions_etc_gshadow
Time: 2014-07-14 14:33
Severity: medium
To properly set the permissions of /etc/gshadow
, run the command:
# chmod 0000 /etc/gshadow
The /etc/gshadow
file contains group password hashes. Protection of this file
is critical for system security.
Security identifiers
- CCE-26951-4
Result for Verify User Who Owns passwd File
Result: pass
Rule ID: file_owner_etc_passwd
Time: 2014-07-14 14:33
Severity: medium
To properly set the owner of /etc/passwd
, run the command:
# chown root /etc/passwd
The /etc/passwd
file contains information about the users that are configured on
the system. Protection of this file is critical for system security.
Security identifiers
- CCE-26953-0
Result for Verify Group Who Owns passwd File
Result: pass
Rule ID: file_groupowner_etc_passwd
Time: 2014-07-14 14:33
Severity: medium
To properly set the group owner of /etc/passwd
, run the command:
# chgrp root /etc/passwd
The /etc/passwd
file contains information about the users that are configured on
the system. Protection of this file is critical for system security.
Security identifiers
- CCE-26856-5
Result for Verify Permissions on passwd File
Result: pass
Rule ID: file_permissions_etc_passwd
Time: 2014-07-14 14:33
Severity: medium
To properly set the permissions of /etc/passwd
, run the command:
# chmod 0644 /etc/passwd
If the /etc/passwd
file is writable by a group-owner or the
world the risk of its compromise is increased. The file contains the list of
accounts on the system and associated information, and protection of this file
is critical for system security.
Security identifiers
- CCE-26868-0
Result for Verify that Shared Library Files Have Restrictive Permissions
Result: pass
Rule ID: file_permissions_library_dirs
Time: 2014-07-14 14:33
Severity: medium
System-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:
# chmod go-w FILE
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Restrictive permissions are necessary to protect the integrity of the system.
Security identifiers
- CCE-27381-3
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
Result for Verify that Shared Library Files Have Root Ownership
Result: pass
Rule ID: file_ownership_library_dirs
Time: 2014-07-14 14:33
Severity: medium
System-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:
# chown root FILE
Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership is necessary to protect the integrity of the system.
Security identifiers
- CCE-27424-1
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
Result for Verify that System Executables Have Restrictive Permissions
Result: pass
Rule ID: file_permissions_binary_dirs
Time: 2014-07-14 14:33
Severity: medium
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:
# chmod go-w FILE
System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.
Security identifiers
- CCE-27289-8
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
Result for Verify that System Executables Have Root Ownership
Result: pass
Rule ID: file_ownership_binary_dirs
Time: 2014-07-14 14:33
Severity: medium
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:
# chown root FILE
System binaries are executed by privileged users as well as system services, and restrictive permissions are necessary to ensure that their execution of these programs cannot be co-opted.
Security identifiers
- CCE-27623-8
Result for Ensure All SGID Executables Are Authorized
Result: pass
Rule ID: no_unpackaged_sgid_files
Time: 2014-07-14 14:34
Severity: low
The SGID (set group id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorized SGID files is determine if any were not installed as part of an RPM package, which is cryptographically verified. Investigate the origin of any unpackaged SGID files.
Executable files with the SGID permission run with the privileges of the owner of the file. SGID files of uncertain provenance could allow for unprivileged users to elevate privileges. The presence of these files should be strictly controlled on the system.
Security identifiers
- CCE-26769-0
Result for Set Daemon Umask
Result: pass
Rule ID: umask_for_daemons
Time: 2014-07-14 14:34
Severity: low
The 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 UMASK
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.
The umask influences the permissions assigned to files created by a process at run time. An unnecessarily permissive umask could result in files being created with insecure permissions.
Security identifiers
- CCE-27031-4
Remediation script
var_umask_for_daemons="022"
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
Result for Disable Core Dumps for All Users
Result: pass
Rule ID: disable_users_coredumps
Time: 2014-07-14 14:34
Severity: low
To disable core dumps for all users, add the following line to
/etc/security/limits.conf
:
* hard core 0
A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.
Security identifiers
- CCE-27033-0
Remediation script
echo "* hard core 0" >> /etc/security/limits.conf
Result for Disable Core Dumps for SUID programs
Result: pass
Rule ID: sysctl_fs_suid_dumpable
Time: 2014-07-14 14:34
Severity: low
To set the runtime status of the fs.suid_dumpable
kernel parameter,
run the following command:
# 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
The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.
Security identifiers
- CCE-27044-7
Remediation script
#
# Set runtime for fs.suid_dumpable
#
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 "" >> /etc/sysctl.conf
echo "# Set fs.suid_dumpable to 0 per security requirements" >> /etc/sysctl.conf
echo "fs.suid_dumpable = 0" >> /etc/sysctl.conf
fi
Result for Enable Randomized Layout of Virtual Address Space
Result: pass
Rule ID: sysctl_kernel_randomize_va_space
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the kernel.randomize_va_space
kernel parameter,
run the following command:
# 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
Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.
Security identifiers
- CCE-26999-3
Remediation script
#
# Set runtime for kernel.randomize_va_space
#
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 "" >> /etc/sysctl.conf
echo "# Set kernel.randomize_va_space to 2 per security requirements" >> /etc/sysctl.conf
echo "kernel.randomize_va_space = 2" >> /etc/sysctl.conf
fi
Result for Enable NX or XD Support in the BIOS
Result: notchecked
Rule ID: bios_enable_execution_restrictions
Time: 2014-07-14 14:34
Severity: low
Reboot the system and enter the BIOS or Setup configuration menu. Navigate the BIOS configuration menu and make sure that the option is enabled. The setting may be located under a Security section. Look for Execute Disable (XD) on Intel-based systems and No Execute (NX) on AMD-based systems.
Computers with the ability to prevent this type of code execution frequently put an option in the BIOS that will allow users to turn the feature on or off at will.
Security identifiers
- CCE-27163-5
Result for Ensure SELinux Not Disabled in /etc/grub.conf
Result: pass
Rule ID: enable_selinux_bootloader
Time: 2014-07-14 14:34
Severity: medium
SELinux can be disabled at boot time by an argument in
/etc/grub.conf
.
Remove any instances of selinux=0
from the kernel arguments in that
file to prevent SELinux from being disabled at boot.
Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.
Security identifiers
- CCE-26956-3
Remediation script
sed -i "s/selinux=0//gI" /etc/grub.conf
sed -i "s/enforcing=0//gI" /etc/grub.conf
Result for Ensure SELinux State is Enforcing
Result: pass
Rule ID: selinux_state
Time: 2014-07-14 14:34
Severity: medium
The 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
Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.
Security identifiers
- CCE-26969-6
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
Result for Configure SELinux Policy
Result: pass
Rule ID: selinux_policytype
Time: 2014-07-14 14:34
Severity: low
The 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.
Setting the SELinux policy to targeted
or a more specialized policy
ensures the system will confine processes that are likely to be
targeted for exploitation, such as network or system services.
Security identifiers
- CCE-26875-5
Remediation script
var_selinux_policy_name="mls"
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
Result for Ensure No Daemons are Unconfined by SELinux
Result: notchecked
Rule ID: selinux_confinement_of_daemons
Time: 2014-07-14 14:34
Severity: medium
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:
# 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.
Daemons which run with the initrc_t
context may cause AVC denials,
or allow privileges that the daemon does not require.
Security identifiers
- CCE-27111-4
Result for Direct root Logins Not Allowed
Result: notchecked
Rule ID: no_direct_root_logins
Time: 2014-07-14 14:34
Severity: medium
To 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:
echo > /etc/securetty
Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.
Security identifiers
- CCE-26891-2
Result for Restrict Virtual Console Root Logins
Result: pass
Rule ID: securetty_root_login_console_only
Time: 2014-07-14 14:34
Severity: medium
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
Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.
Security identifiers
- CCE-26855-7
Remediation script
sed -i '/^vc\//d' /etc/securetty
Result for Restrict Serial Port Root Logins
Result: pass
Rule ID: restrict_serial_port_logins
Time: 2014-07-14 14:34
Severity: low
To restrict root logins on serial ports,
ensure lines of this form do not appear in /etc/securetty
:
ttyS0
ttyS1
Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.
Security identifiers
- CCE-27047-0
Result for Verify Only Root Has UID 0
Result: pass
Rule ID: accounts_no_uid_except_zero
Time: 2014-07-14 14:34
Severity: medium
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.
An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.
Security identifiers
- CCE-26971-2
Remediation script
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs passwd -l
Result for Prevent Log In to Accounts With Empty Password
Result: pass
Rule ID: no_empty_passwords
Time: 2014-07-14 14:34
Severity: high
If an account is configured for password authentication
but does not have an assigned password, it may be possible to log
into the account without authentication. Remove any instances of the nullok
option in /etc/pam.d/system-auth
to
prevent logins with empty passwords.
If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.
Security identifiers
- CCE-27038-9
Remediation script
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth
Result for Verify All Account Password Hashes are Shadowed
Result: pass
Rule ID: accounts_password_all_shadowed
Time: 2014-07-14 14:34
Severity: medium
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.
The hashes for all user account passwords should be stored in
the file /etc/shadow
and never in /etc/passwd
,
which is readable by all users.
Security identifiers
- CCE-26476-2
Result for Verify No netrc Files Exist
Result: pass
Rule ID: no_netrc_files
Time: 2014-07-14 14:34
Severity: medium
The .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.
Unencrypted passwords for remote FTP servers may be stored in .netrc
files. DoD policy requires passwords be encrypted in storage and not used
in access scripts.
Security identifiers
- CCE-27225-2
Result for Set Password Minimum Length in login.defs
Result: pass
Rule ID: accounts_password_minlen_login_defs
Time: 2014-07-14 14:34
Severity: medium
To 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.
Requiring a minimum password length makes password cracking attacks more difficult by ensuring a larger search space. However, any security benefit from an onerous requirement must be carefully weighed against usability problems, support costs, or counterproductive behavior that may result.
Security identifiers
- CCE-27002-5
Remediation script
var_accounts_password_minlen_login_defs="12"
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
Result for Set Password Maximum Age
Result: pass
Rule ID: accounts_maximum_age_login_defs
Time: 2014-07-14 14:34
Severity: medium
To specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line, replacing DAYS appropriately:
PASS_MAX_DAYS DAYS
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
Setting the password maximum age ensures users are required to periodically change their passwords. This could possibly decrease the utility of a stolen password. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.
Security identifiers
- CCE-26985-2
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
Result for Set Password Warning Age
Result: pass
Rule ID: accounts_password_warn_age_login_defs
Time: 2014-07-14 14:34
Severity: low
To 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, replacing DAYS appropriately:
PASS_WARN_AGE DAYS
The DoD requirement is 7.
Setting the password warning age enables users to make the change at a practical time.
Security identifiers
- CCE-26988-6
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 $var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi
Result for Set Account Expiration Following Inactivity
Result: pass
Rule ID: account_disable_post_pw_expiration
Time: 2014-07-14 14:34
Severity: low
To specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following lines in /etc/default/useradd
, substituting
NUM_DAYS
appropriately:
INACTIVE=NUM_DAYS
A value of 35 is recommended.
If a password is currently on the
verge of expiration, then 35 days remain until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 95
days could elapse until the account would be automatically disabled. See the
useradd
man page for more information. Determining the inactivity
timeout must be done with careful consideration of the length of a "normal"
period of inactivity for users in the particular environment. Setting
the timeout too low incurs support costs and also has the potential to impact
availability of the system to legitimate users.
Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.
Security identifiers
- CCE-27283-1
Remediation script
var_account_disable_post_pw_expiration="35"
grep -q ^INACTIVE /etc/default/useradd && \
sed -i "s/INACTIVE.*/INACTIVE=$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
Result for Assign Expiration Date to Temporary Accounts
Result: notchecked
Rule ID: account_temp_expire_date
Time: 2014-07-14 14:34
Severity: low
In the event temporary or emergency accounts are required, configure the system
to terminate them after a documented time period. For every temporary and
emergency account, run the following command to set an expiration date on it,
substituting USER
and YYYY-MM-DD
appropriately:
# chage -E YYYY-MM-DD USER
YYYY-MM-DD
indicates the documented expiration date for the account.
When temporary and emergency accounts are created, there is a risk they may
remain in place and active after the need for them no longer exists. Account
expiration greatly reduces the risk of accounts being misused or hijacked.
Security identifiers
- CCE-27474-6
Result for Set Password Retry Prompts Permitted Per-Session
Result: pass
Rule ID: accounts_password_pam_cracklib_retry
Time: 2014-07-14 14:34
Severity: low
To 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.
Setting the password retry prompts that are permitted on a per-session basis to a low value requires some software, such as SSH, to re-connect. This can slow down and draw additional attention to some types of password-guessing attacks. Note that this is different from account lockout, which is provided by the pam_faillock module.
Security identifiers
- CCE-27123-9
Result for Set Password to Maximum of Three Consecutive Repeating Characters
Result: notchecked
Rule ID: password_require_consecrepeat
Time: 2014-07-14 14:34
Severity: low
The pam_cracklib module's maxrepeat
parameter controls requirements for
consecutive repeating characters. When set to a positive number, it will reject passwords
which contain more than that number of consecutive characters. Add maxrepeat=3
after pam_cracklib.so to prevent a run of four or more identical characters.
Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.
Security identifiers
- CCE-27227-8
Result for Set Password Strength Minimum Digit Characters
Result: pass
Rule ID: accounts_password_pam_cracklib_dcredit
Time: 2014-07-14 14:34
Severity: low
The 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.
Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.
Security identifiers
- CCE-26374-9
Result for Set Password Strength Minimum Uppercase Characters
Result: pass
Rule ID: accounts_password_pam_cracklib_ucredit
Time: 2014-07-14 14:34
Severity: low
The 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.
Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.
Security identifiers
- CCE-26601-5
Result for Set Password Strength Minimum Special Characters
Result: pass
Rule ID: accounts_password_pam_cracklib_ocredit
Time: 2014-07-14 14:34
Severity: low
The 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.
Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.
Security identifiers
- CCE-26409-3
Result for Set Password Strength Minimum Lowercase Characters
Result: pass
Rule ID: accounts_password_pam_cracklib_lcredit
Time: 2014-07-14 14:34
Severity: low
The 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.
Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.
Security identifiers
- CCE-26631-2
Result for Set Password Strength Minimum Different Characters
Result: pass
Rule ID: accounts_password_pam_cracklib_difok
Time: 2014-07-14 14:34
Severity: low
The pam_cracklib module's difok
parameter controls requirements for
usage of different characters during a password change.
Add difok=NUM
after pam_cracklib.so to require differing
characters when changing passwords, substituting NUM appropriately.
The DoD requirement is 4
.
Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.
Security identifiers
- CCE-26615-5
Result for Limit Password Reuse
Result: pass
Rule ID: accounts_password_reuse_limit
Time: 2014-07-14 14:34
Severity: medium
Do 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=24
to the
line which refers to the pam_unix.so
module, as shown:
password sufficient pam_unix.so existing_options remember=24
The DoD and FISMA requirement is 24 passwords.
Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.
Security identifiers
- CCE-26741-9
Result for Set Password Hashing Algorithm in /etc/login.defs
Result: pass
Rule ID: set_password_hashing_algorithm_logindefs
Time: 2014-07-14 14:34
Severity: medium
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
Using a stronger hashing algorithm makes password cracking attacks more difficult.
Security identifiers
- CCE-27228-6
Result for Set Password Hashing Algorithm in /etc/libuser.conf
Result: pass
Rule ID: set_password_hashing_algorithm_libuserconf
Time: 2014-07-14 14:34
Severity: medium
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
Using a stronger hashing algorithm makes password cracking attacks more difficult.
Security identifiers
- CCE-27229-4
Result for Limit the Number of Concurrent Login Sessions Allowed Per User
Result: unknown
Rule ID: accounts_max_concurrent_login_sessions
Time: 2014-07-14 14:34
Severity: low
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 10
Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.
Security identifiers
- CCE-27457-1
Remediation script
var_accounts_max_concurrent_login_sessions="1"
echo "* hard maxlogins $var_accounts_max_concurrent_login_sessions" >> /etc/security/limits.conf
Result for Set Boot Loader Password
Result: pass
Rule ID: bootloader_password
Time: 2014-07-14 14:34
Severity: medium
The 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.
Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.
Security identifiers
- CCE-26911-8
Result for Disable Interactive Boot
Result: pass
Rule ID: disable_interactive_boot
Time: 2014-07-14 14:34
Severity: medium
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.
Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.
Security identifiers
- CCE-27043-9
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
Result for GNOME Desktop Screensaver Mandatory Use
Result: pass
Rule ID: enable_screensaver_after_idle
Time: 2014-07-14 14:34
Severity: medium
Run the following command to activate the screensaver 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
Enabling idle activation of the screen saver ensures the screensaver will be activated after the idle delay. Applications requiring continuous, real-time screen display (such as network management products) require the login session does not have administrator rights and the display station is located in a controlled-access area.
Security identifiers
- CCE-26600-7
Result for Enable Screen Lock Activation After Idle Period
Result: pass
Rule ID: enable_screensaver_password_lock
Time: 2014-07-14 14:34
Severity: medium
Run the following command to activate locking of the screensaver in the GNOME desktop when it is activated:
# gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type bool \
--set /apps/gnome-screensaver/lock_enabled true
Enabling the activation of the screen lock after an idle period ensures password entry will be required in order to access the system, preventing access by passersby.
Security identifiers
- CCE-26235-2
Result for Implement Blank Screen Saver
Result: pass
Rule ID: set_blank_screensaver
Time: 2014-07-14 14:34
Severity: low
Run the following command to set the screensaver mode in the GNOME desktop to a blank screen:
# gconftool-2 --direct \
--config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
--type string \
--set /apps/gnome-screensaver/mode blank-only
Setting the screensaver mode to blank-only conceals the contents of the display from passersby.
Security identifiers
- CCE-26638-7
Result for Set GUI Warning Banner Text
Result: notchecked
Rule ID: set_gdm_login_banner_text
Time: 2014-07-14 14:34
Severity: medium
To set the text shown by the GNOME Display Manager in the login screen, run the following command:
sudo -u gdm gconftool-2 \
--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 to the file /var/lib/gdm/.gconf/apps/gdm/simple-greeter/%gconf.xml
,
and this file can later be edited directly if necessary.
An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.
Security identifiers
- CCE-27017-3
Result for Disable Zeroconf Networking
Result: pass
Rule ID: network_disable_zeroconf
Time: 2014-07-14 14:34
Severity: low
Zeroconf 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
Zeroconf addresses are in the network 169.254.0.0. The networking scripts add entries to the system's routing table for these addresses. Zeroconf address assignment commonly occurs when the system is configured to use DHCP but fails to receive an address assignment from the DHCP server.
Security identifiers
- CCE-27151-0
Remediation script
echo "NOZEROCONF=yes" >> /etc/sysconfig/network
Result for Ensure System is Not Acting as a Network Sniffer
Result: pass
Rule ID: network_sniffer_disabled
Time: 2014-07-14 14:34
Severity: low
The 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
If any results are returned, then a sniffing process (such as tcpdump or Wireshark) is likely to be using the interface and this should be investigated.
Security identifiers
- CCE-27152-8
Result for Disable Kernel Parameter for Sending ICMP Redirects by Default
Result: pass
Rule ID: sysctl_net_ipv4_conf_default_send_redirects
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.default.send_redirects
kernel parameter,
run the following command:
# 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
Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.
Security identifiers
- CCE-27001-7
Remediation script
#
# Set runtime for net.ipv4.conf.default.send_redirects
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Sending ICMP Redirects for All Interfaces
Result: pass
Rule ID: sysctl_ipv4_all_send_redirects
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.all.send_redirects
kernel parameter,
run the following command:
# 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
Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.
Security identifiers
- CCE-27004-1
Result for Disable Kernel Parameter for IP Forwarding
Result: pass
Rule ID: sysctl_ipv4_ip_forward
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.ip_forward
kernel parameter,
run the following command:
# 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
IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.
Security identifiers
- CCE-26866-4
Result for Disable Kernel Parameter for Accepting Source-Routed Packets for All Interfaces
Result: pass
Rule ID: sysctl_net_ipv4_conf_all_accept_source_route
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.all.accept_source_route
kernel parameter,
run the following command:
# 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
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-27037-1
Remediation script
#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Accepting ICMP Redirects for All Interfaces
Result: pass
Rule ID: sysctl_net_ipv4_conf_all_accept_redirects
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.all.accept_redirects
kernel parameter,
run the following command:
# 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
Accepting ICMP redirects has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-27027-2
Remediation script
#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Accepting Secure Redirects for All Interfaces
Result: pass
Rule ID: sysctl_net_ipv4_conf_all_secure_redirects
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.all.secure_redirects
kernel parameter,
run the following command:
# 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
Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-26854-0
Remediation script
#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Enable Kernel Parameter to Log Martian Packets
Result: pass
Rule ID: sysctl_net_ipv4_conf_all_log_martians
Time: 2014-07-14 14:34
Severity: low
To set the runtime status of the net.ipv4.conf.all.log_martians
kernel parameter,
run the following command:
# 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
The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.
Security identifiers
- CCE-27066-0
Remediation script
#
# Set runtime for net.ipv4.conf.all.log_martians
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Accepting Source-Routed Packets By Default
Result: pass
Rule ID: sysctl_net_ipv4_conf_default_accept_source_route
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.default.accept_source_route
kernel parameter,
run the following command:
# 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
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-26983-7
Remediation script
#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Accepting ICMP Redirects By Default
Result: pass
Rule ID: sysctl_net_ipv4_conf_default_accept_redirects
Time: 2014-07-14 14:34
Severity: low
To set the runtime status of the net.ipv4.conf.default.accept_redirects
kernel parameter,
run the following command:
# 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
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-27015-7
Remediation script
#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable Kernel Parameter for Accepting Secure Redirects By Default
Result: pass
Rule ID: sysctl_net_ipv4_conf_default_secure_redirects
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.default.secure_redirects
kernel parameter,
run the following command:
# 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
Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
Security identifiers
- CCE-26831-8
Remediation script
#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests
Result: pass
Rule ID: sysctl_net_ipv4_icmp_echo_ignore_broadcasts
Time: 2014-07-14 14:34
Severity: low
To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts
kernel parameter,
run the following command:
# 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
Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.
Security identifiers
- CCE-26883-9
Remediation script
#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Enable Kernel Parameter to Ignore Bogus ICMP Error Responses
Result: pass
Rule ID: sysctl_net_ipv4_icmp_ignore_bogus_error_responses
Time: 2014-07-14 14:34
Severity: low
To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses
kernel parameter,
run the following command:
# 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
Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.
Security identifiers
- CCE-26993-6
Remediation script
#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Enable Kernel Parameter to Use TCP Syncookies
Result: pass
Rule ID: sysctl_net_ipv4_tcp_syncookies
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.tcp_syncookies
kernel parameter,
run the following command:
# 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
A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.
Security identifiers
- CCE-27053-8
Remediation script
#
# Set runtime for net.ipv4.tcp_syncookies
#
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 "" >> /etc/sysctl.conf
echo "# Set net.ipv4.tcp_syncookies to 1 per security requirements" >> /etc/sysctl.conf
echo "net.ipv4.tcp_syncookies = 1" >> /etc/sysctl.conf
fi
Result for Enable Kernel Parameter to Use Reverse Path Filtering for All Interfaces
Result: pass
Rule ID: sysctl_net_ipv4_conf_all_rp_filter
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.all.rp_filter
kernel parameter,
run the following command:
# 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
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
Security identifiers
- CCE-26979-5
Remediation script
#
# Set runtime for net.ipv4.conf.all.rp_filter
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Enable Kernel Parameter to Use Reverse Path Filtering by Default
Result: pass
Rule ID: sysctl_net_ipv4_conf_default_rp_filter
Time: 2014-07-14 14:34
Severity: medium
To set the runtime status of the net.ipv4.conf.default.rp_filter
kernel parameter,
run the following command:
# 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
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
Security identifiers
- CCE-26915-9
Remediation script
#
# Set runtime for net.ipv4.conf.default.rp_filter
#
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 "" >> /etc/sysctl.conf
echo "# 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
Result for Disable WiFi or Bluetooth BIOS
Result: notchecked
Rule ID: wireless_disable_in_bios
Time: 2014-07-14 14:34
Severity: low
Some 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.
Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.
Security identifiers
- CCE-26878-9
Result for Deactivate Wireless Network Interfaces
Result: pass
Rule ID: deactivate_wireless_interfaces
Time: 2014-07-14 14:34
Severity: low
Deactivating 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 also be used to
determine whether wireless support ('extensions') 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:
# 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
:
# rm /etc/sysconfig/network-scripts/ifcfg-interface
Wireless networking allows attackers within physical proximity to launch network-based attacks against systems, including those against local LAN protocols which were not designed with security in mind.
Security identifiers
- CCE-27057-9
Result for Disable Bluetooth Service
Result: pass
Rule ID: service_bluetooth_disabled
Time: 2014-07-14 14:34
Severity: medium
The bluetooth
service can be disabled with the following command:
# chkconfig bluetooth off
# service bluetooth stop
Disabling the bluetooth
service prevents the system from attempting
connections to Bluetooth devices, which entails some security risk.
Nevertheless, variation in this risk decision may be expected due to the
utility of Bluetooth connectivity and its limited range.
Security identifiers
- CCE-27081-9
Remediation script
#
# Disable bluetooth for all run levels
#
chkconfig --level 0123456 bluetooth off
#
# Stop bluetooth if currently running
#
service bluetooth stop
Result for Disable Bluetooth Kernel Modules
Result: pass
Rule ID: kernel_module_bluetooth_disabled
Time: 2014-07-14 14:34
Severity: medium
The 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 net-pf-31 /bin/false
install bluetooth /bin/false
If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.
Security identifiers
- CCE-26763-3
Result for Disable IPv6 Networking Support Automatic Loading
Result: pass
Rule ID: kernel_module_ipv6_option_disabled
Time: 2014-07-14 14:34
Severity: medium
To prevent the IPv6 kernel module (ipv6
) from loading 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.
Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.
Security identifiers
- CCE-27153-6
Result for Disable Support for RPC IPv6
Result: pass
Rule ID: network_ipv6_disable_rpc
Time: 2014-07-14 14:34
Severity: low
RPC 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 - -
Security identifiers
- CCE-27232-8
Result for Verify iptables Enabled
Result: pass
Rule ID: service_iptables_enabled
Time: 2014-07-14 14:34
Severity: medium
The iptables
service can be enabled with the following command:
# chkconfig --level 2345 iptables on
The iptables
service provides the system's host-based firewalling
capability for IPv4 and ICMP.
Security identifiers
- CCE-27018-1
Remediation script
#
# Enable iptables for all run levels
#
chkconfig --level 0123456 iptables on
#
# Start iptables if not currently running
#
service iptables start
Result for Set Default iptables Policy for Incoming Packets
Result: pass
Rule ID: set_iptables_default_rule
Time: 2014-07-14 14:34
Severity: medium
To set the default policy to DROP (instead of ACCEPT) for
the built-in INPUT chain which processes incoming packets,
add or correct the following line in
/etc/sysconfig/iptables
:
:INPUT DROP [0:0]
In iptables
the default policy is applied only after all
the applicable rules in the table are examined for a match. Setting the
default policy to DROP
implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted.
Security identifiers
- CCE-26444-0
Result for Set Default iptables Policy for Forwarded Packets
Result: notchecked
Rule ID: set_iptables_default_rule_forward
Time: 2014-07-14 14:34
Severity: medium
To set the default policy to DROP (instead of ACCEPT) for
the built-in FORWARD chain which processes packets that will be forwarded from
one interface to another,
add or correct the following line in
/etc/sysconfig/iptables
:
:FORWARD DROP [0:0]
In iptables
the default policy is applied only after all
the applicable rules in the table are examined for a match. Setting the
default policy to DROP
implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted.
Security identifiers
- CCE-27186-6
Result for Disable DCCP Support
Result: pass
Rule ID: kernel_module_dccp_disabled
Time: 2014-07-14 14:34
Severity: medium
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/false
Disabling DCCP protects the system against exploitation of any flaws in its implementation.
Security identifiers
- CCE-26448-1
Remediation script
echo "install dccp /bin/false" > /etc/modprobe.d/dccp.conf
Result for Disable SCTP Support
Result: pass
Rule ID: kernel_module_sctp_disabled
Time: 2014-07-14 14:34
Severity: medium
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/false
Disabling SCTP protects the system against exploitation of any flaws in its implementation.
Security identifiers
- CCE-26410-1
Remediation script
echo "install sctp /bin/false" > /etc/modprobe.d/sctp.conf
Result for Disable RDS Support
Result: pass
Rule ID: kernel_module_rds_disabled
Time: 2014-07-14 14:34
Severity: low
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/false
Disabling RDS protects the system against exploitation of any flaws in its implementation.
Security identifiers
- CCE-26239-4
Remediation script
echo "install rds /bin/false" > /etc/modprobe.d/rds.conf
Result for Disable TIPC Support
Result: pass
Rule ID: kernel_module_tipc_disabled
Time: 2014-07-14 14:34
Severity: medium
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/false
Disabling TIPC protects the system against exploitation of any flaws in its implementation.
Security identifiers
- CCE-26696-5
Remediation script
echo "install tipc /bin/false" > /etc/modprobe.d/tipc.conf
Result for Ensure rsyslog is Installed
Result: pass
Rule ID: package_rsyslog_installed
Time: 2014-07-14 14:34
Severity: medium
Rsyslog is installed by default.
The rsyslog
package can be installed with the following command:
# yum install rsyslog
The rsyslog package provides the rsyslog daemon, which provides system logging services.
Security identifiers
- CCE-26809-4
Remediation script
yum -y install rsyslog
Result for Enable rsyslog Service
Result: pass
Rule ID: service_rsyslog_enabled
Time: 2014-07-14 14:34
Severity: medium
The rsyslog
service provides syslog-style logging by default on RHEL 6.
The rsyslog
service can be enabled with the following command:
# chkconfig --level 2345 rsyslog on
The rsyslog
service must be running in order to provide
logging services, which are essential to system administration.
Security identifiers
- CCE-26807-8
Remediation script
#
# Enable rsyslog for all run levels
#
chkconfig --level 0123456 rsyslog on
#
# Start rsyslog if not currently running
#
service rsyslog start
Result for Ensure Log Files Are Owned By Appropriate Group
Result: unknown
Rule ID: groupowner_rsyslog_files
Time: 2014-07-14 14:34
Severity: medium
The 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:
# chgrp root LOGFILE
The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.
Security identifiers
- CCE-26821-9
Result for Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
Result: pass
Rule ID: rsyslog_accept_remote_messages_none
Time: 2014-07-14 14:34
Severity: low
The 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
Any process which receives messages from the network incurs some risk of receiving malicious messages. This risk can be eliminated for rsyslog by configuring it not to listen on the network.
Security identifiers
- CCE-26803-7
Result for Enable rsyslog to Accept Messages via TCP, if Acting As Log Server
Result: notchecked
Rule ID: rsyslog_accept_remote_messages_tcp
Time: 2014-07-14 14:34
Severity: low
The rsyslog
daemon should not accept remote messages
unless the system acts as a log server.
If the system needs to act as a central log server, add the following lines to
/etc/rsyslog.conf
to enable reception of messages over TCP:
$ModLoad imtcp
$InputTCPServerRun 514
If the system needs to act as a log server, this ensures that it can receive messages over a reliable TCP connection.
Security identifiers
- CCE-27235-1
Result for Enable rsyslog to Accept Messages via UDP, if Acting As Log Server
Result: notchecked
Rule ID: rsyslog_accept_remote_messages_udp
Time: 2014-07-14 14:34
Severity: low
The rsyslog
daemon should not accept remote messages
unless the system acts as a log server.
If the system needs to act as a central log server, add the following lines to
/etc/rsyslog.conf
to enable reception of messages over UDP:
$ModLoad imudp
$UDPServerRun 514
Many devices, such as switches, routers, and other Unix-like systems, may only support the traditional syslog transmission over UDP. If the system must act as a log server, this enables it to receive their messages as well.
Security identifiers
- CCE-27236-9
Result for Ensure Logrotate Runs Periodically
Result: pass
Rule ID: ensure_logrotate_activated
Time: 2014-07-14 14:34
Severity: low
The 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
Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.
Security identifiers
- CCE-27014-0
Result for Enable auditd Service
Result: pass
Rule ID: service_auditd_enabled
Time: 2014-07-14 14:34
Severity: medium
The auditd
service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd
service can be enabled with the following command:
# chkconfig --level 2345 auditd on
Ensuring the auditd
service is active ensures
audit records generated by the kernel can be written to disk, or that appropriate
actions will be taken if other obstacles exist.
Security identifiers
- CCE-27058-7
Remediation script
#
# Enable auditd for all run levels
#
chkconfig --level 0123456 auditd on
#
# Start auditd if not currently running
#
service auditd start
Result for Enable Auditing for Processes Which Start Prior to the Audit Daemon
Result: pass
Rule ID: enable_auditd_bootloader
Time: 2014-07-14 14:34
Severity: medium
To ensure all processes can be audited, even
those which start prior to the audit daemon, add the argument
audit=1
to the kernel line in /etc/grub.conf
, in the manner below:
kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1
Each process on the system carries an "auditable" flag which
indicates whether its activities can be audited. Although auditd
takes care of enabling this for all processes which launch after it
does, adding the kernel argument ensures it is set for every
process during boot.
Security identifiers
- CCE-26785-6
Result for Configure auditd Number of Logs Retained
Result: pass
Rule ID: configure_auditd_num_logs
Time: 2014-07-14 14:34
Severity: medium
Determine how many log files
auditd
should retain when it rotates logs.
Edit the file /etc/audit/auditd.conf
. Add or modify the following
line, substituting NUMLOGS with the correct value:
num_logs = NUMLOGS
Set the value to 5 for general-purpose systems.
Note that values less than 2 result in no log rotation.
The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.
Security identifiers
- CCE-27522-2
Result for Configure auditd Max Log File Size
Result: pass
Rule ID: configure_auditd_max_log_file
Time: 2014-07-14 14:34
Severity: medium
Determine the amount of audit data (in megabytes)
which should be retained in each log file. Edit the file
/etc/audit/auditd.conf
. Add or modify the following line, substituting
the correct value for STOREMB:
max_log_file = STOREMB
Set the value to 6
(MB) or higher for general-purpose systems.
Larger values, of course,
support retention of even more audit data.
The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.
Security identifiers
- CCE-27550-3
Result for Configure auditd max_log_file_action Upon Reaching Maximum Log Size
Result: pass
Rule ID: configure_auditd_max_log_file_action
Time: 2014-07-14 14:34
Severity: medium
The default action to take when the logs reach their maximum size
is to rotate the log files, discarding the oldest one. To configure the action taken
by auditd
, add or correct the line in /etc/audit/auditd.conf
:
max_log_file_action = ACTION
Possible values for ACTION are described in the auditd.conf
man
page. These include:
-
ignore
-
syslog
-
suspend
-
rotate
-
keep_logs
Set the ACTION
to rotate
to ensure log rotation
occurs. This is the default. The setting is case-insensitive.
Automatically rotating logs (by setting this to rotate
)
minimizes the chances of the system unexpectedly running out of disk space by
being overwhelmed with log data. However, for systems that must never discard
log data, or which use external processes to transfer it and reclaim space,
keep_logs
can be employed.
Security identifiers
- CCE-27237-7
Result for Configure auditd space_left Action on Low Disk Space
Result: pass
Rule ID: auditd_data_retention_space_left_action
Time: 2014-07-14 14:34
Severity: medium
The auditd
service can be configured to take an action
when disk space starts to run low.
Edit the file /etc/audit/auditd.conf
. Modify the following line,
substituting ACTION appropriately:
space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf
man page.
These include:
-
ignore
-
syslog
-
email
-
exec
-
suspend
-
single
-
halt
Set this to email
(instead of the default,
which is suspend
) as it is more likely to get prompt attention. Acceptable values
also include suspend
, single
, and halt
.
Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.
Security identifiers
- CCE-27238-5
Result for Configure auditd admin_space_left Action on Low Disk Space
Result: pass
Rule ID: auditd_data_retention_admin_space_left_action
Time: 2014-07-14 14:34
Severity: medium
The auditd
service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf
. Add or modify the following line,
substituting ACTION appropriately:
admin_space_left_action = ACTION
Set this value to single
to cause the system to switch to single user
mode for corrective action. Acceptable values also include suspend
and
halt
. For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined. Details regarding all possible values for ACTION are described in the
auditd.conf
man page.
Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.
Security identifiers
- CCE-27239-3
Remediation script
var_auditd_admin_space_left_action="single"
grep -q ^admin_space_left_action /etc/audit/auditd.conf && \
sed -i "s/admin_space_left_action.*/admin_space_left_action = $var_auditd_admin_space_left_action/g" /etc/audit/auditd.conf
if ! [ $? -eq 0 ]; then
echo "admin_space_left_action = $var_auditd_admin_space_left_action" >> /etc/audit/auditd.conf
fi
Result for Configure auditd mail_acct Action on Low Disk Space
Result: pass
Rule ID: auditd_data_retention_action_mail_acct
Time: 2014-07-14 14:34
Severity: medium
The auditd
service can be configured to send email to
a designated account in certain situations. Add or correct the following line
in /etc/audit/auditd.conf
to ensure that administrators are notified
via email for those situations:
action_mail_acct = root
Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.
Security identifiers
- CCE-27241-9
Result for Configure auditd to use audispd plugin
Result: notchecked
Rule ID: configure_auditd_audispd
Time: 2014-07-14 14:34
Severity: medium
To configure the auditd
service to use the
audispd
plugin, set the active
line in
/etc/audisp/plugins.d/syslog.conf
to yes
.
Restart the auditd
service:
# service auditd restart
The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include an audit event multiplexor plugin (audispd) to pass audit records to the local syslog server
Security identifiers
- CCE-26933-2
Result for Record attempts to alter time through adjtimex
Result: pass
Rule ID: audit_rules_time_adjtimex
Time: 2014-07-14 14:34
Severity: low
On 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
Arbitrary 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 (such as sshd). All changes to the system time should be audited.
Security identifiers
- CCE-26242-8
Result for Record attempts to alter time through settimeofday
Result: pass
Rule ID: audit_rules_time_settimeofday
Time: 2014-07-14 14:34
Severity: low
On 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
Arbitrary 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 (such as sshd). All changes to the system time should be audited.
Security identifiers
- CCE-27203-9
Result for Record Attempts to Alter Time Through stime
Result: pass
Rule ID: audit_rules_time_stime
Time: 2014-07-14 14:34
Severity: low
On 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
Arbitrary 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 (such as sshd). All changes to the system time should be audited.
Security identifiers
- CCE-27169-2
Result for Record Attempts to Alter Time Through clock_settime
Result: pass
Rule ID: audit_rules_time_clock_settime
Time: 2014-07-14 14:34
Severity: low
On 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
Arbitrary 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 (such as sshd). All changes to the system time should be audited.
Security identifiers
- CCE-27170-0
Result for Record Attempts to Alter the localtime File
Result: pass
Rule ID: audit_rules_time_watch_localtime
Time: 2014-07-14 14:34
Severity: low
Add 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.
Arbitrary 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 (such as sshd). All changes to the system time should be audited.
Security identifiers
- CCE-27172-6
Result for Record Events that Modify User/Group Information
Result: pass
Rule ID: audit_account_changes
Time: 2014-07-14 14:34
Severity: low
Add the following to /etc/audit/audit.rules
, in order
to capture events that modify account changes:
# audit_account_changes
-w /etc/group -p wa -k audit_account_changes
-w /etc/passwd -p wa -k audit_account_changes
-w /etc/gshadow -p wa -k audit_account_changes
-w /etc/shadow -p wa -k audit_account_changes
-w /etc/security/opasswd -p wa -k audit_account_changes
In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Security identifiers
- CCE-26664-3
Result for Record Events that Modify the System's Network Environment
Result: pass
Rule ID: audit_network_modifications
Time: 2014-07-14 14:34
Severity: low
Add the following to /etc/audit/audit.rules
, setting
ARCH to either b32 or b64 as appropriate for your system:
# audit_network_modifications
-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_network_modifications
-w /etc/issue -p wa -k audit_network_modifications
-w /etc/issue.net -p wa -k audit_network_modifications
-w /etc/hosts -p wa -k audit_network_modifications
-w /etc/sysconfig/network -p wa -k audit_network_modifications
The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.
Security identifiers
- CCE-26648-6
Result for System Audit Logs Must Have Mode 0640 or Less Permissive
Result: pass
Rule ID: file_permissions_var_log_audit
Time: 2014-07-14 14:34
Severity: low
Change the mode of the audit log files with the following command:
# chmod 0640 audit_file
If users can write to audit logs, audit trails can be modified or destroyed.
Security identifiers
- CCE-27243-5
Result for System Audit Logs Must Be Owned By Root
Result: pass
Rule ID: audit_logs_rootowner
Time: 2014-07-14 14:34
Severity: low
To properly set the owner of /var/log
, run the command:
# chown root /var/log
Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.
Security identifiers
- CCE-27244-3
Result for Record Events that Modify the System's Mandatory Access Controls
Result: pass
Rule ID: audit_mac_changes
Time: 2014-07-14 14:34
Severity: low
Add the following to /etc/audit/audit.rules
:
-w /etc/selinux/ -p wa -k MAC-policy
The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.
Security identifiers
- CCE-26657-7
Result for Record Events that Modify the System's Discretionary Access Controls - chmod
Result: pass
Rule ID: audit_rules_dac_modification_chmod
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-26280-8
Result for Record Events that Modify the System's Discretionary Access Controls - chown
Result: pass
Rule ID: audit_rules_dac_modification_chown
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27173-4
Result for Record Events that Modify the System's Discretionary Access Controls - fchmod
Result: pass
Rule ID: audit_rules_dac_modification_fchmod
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27174-2
Result for Record Events that Modify the System's Discretionary Access Controls - fchmodat
Result: pass
Rule ID: audit_rules_dac_modification_fchmodat
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27175-9
Result for Record Events that Modify the System's Discretionary Access Controls - fchown
Result: pass
Rule ID: audit_rules_dac_modification_fchown
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27177-5
Result for Record Events that Modify the System's Discretionary Access Controls - fchownat
Result: pass
Rule ID: audit_rules_dac_modification_fchownat
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27178-3
Result for Record Events that Modify the System's Discretionary Access Controls - fremovexattr
Result: pass
Rule ID: audit_rules_dac_modification_fremovexattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27179-1
Result for Record Events that Modify the System's Discretionary Access Controls - fsetxattr
Result: pass
Rule ID: audit_rules_dac_modification_fsetxattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27180-9
Result for Record Events that Modify the System's Discretionary Access Controls - lchown
Result: pass
Rule ID: audit_rules_dac_modification_lchown
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27181-7
Result for Record Events that Modify the System's Discretionary Access Controls - lremovexattr
Result: pass
Rule ID: audit_rules_dac_modification_lremovexattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27182-5
Result for Record Events that Modify the System's Discretionary Access Controls - lsetxattr
Result: pass
Rule ID: audit_rules_dac_modification_lsetxattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27183-3
Result for Record Events that Modify the System's Discretionary Access Controls - removexattr
Result: pass
Rule ID: audit_rules_dac_modification_removexattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27184-1
Result for Record Events that Modify the System's Discretionary Access Controls - setxattr
Result: pass
Rule ID: audit_rules_dac_modification_setxattr
Time: 2014-07-14 14:34
Severity: low
At 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
Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Security identifiers
- CCE-27185-8
Result for Record Attempts to Alter Logon and Logout Events
Result: pass
Rule ID: audit_manual_logon_edits
Time: 2014-07-14 14:34
Severity: low
The audit system already collects login info for all users and root. To watch for attempted manual edits of
files involved in storing logon 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
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Security identifiers
- CCE-26691-6
Result for Record Attempts to Alter Process and Session Initiation Information
Result: pass
Rule ID: audit_manual_session_edits
Time: 2014-07-14 14:34
Severity: low
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
Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Security identifiers
- CCE-26610-6
Result for Ensure auditd Collects Information on the Use of Privileged Commands
Result: notchecked
Rule ID: audit_privileged_commands
Time: 2014-07-14 14:34
Severity: low
At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid programs:
# find / -xdev -type f -perm -4000 -o -perm -2000 2>/dev/null
Then, for each setuid 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 program
in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.
Security identifiers
- CCE-26457-2
Result for Ensure auditd Collects Information on Exporting to Media (successful)
Result: pass
Rule ID: audit_media_exports
Time: 2014-07-14 14:34
Severity: low
At 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
The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.
Security identifiers
- CCE-26573-6
Result for Ensure auditd Collects System Administrator Actions
Result: pass
Rule ID: audit_sysadmin_actions
Time: 2014-07-14 14:34
Severity: low
At a minimum the audit system should collect
administrator actions for all users and root. Add the following to
/etc/audit/audit.rules
:
-w /etc/sudoers -p wa -k actions
The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.
Security identifiers
- CCE-26662-7
Result for Ensure auditd Collects Information on Kernel Module Loading and Unloading
Result: pass
Rule ID: audit_kernel_module_loading
Time: 2014-07-14 14:34
Severity: low
Add 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
The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
Security identifiers
- CCE-26611-4
Result for Make the auditd Configuration Immutable
Result: pass
Rule ID: audit_config_immutable
Time: 2014-07-14 14:34
Severity: low
Add 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.
Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation
Security identifiers
- CCE-26612-2
Result for Uninstall rsh-server Package
Result: pass
Rule ID: uninstall_rsh-server
Time: 2014-07-14 14:34
Severity: high
The rsh-server
package can be uninstalled with
the following command:
# yum erase rsh-server
The rsh-server
package provides several obsolete and insecure
network services. Removing it
decreases the risk of those services' accidental (or intentional)
activation.
Security identifiers
- CCE-27062-9
Result for Disable rexec Service
Result: pass
Rule ID: disable_rexec
Time: 2014-07-14 14:34
Severity: high
The rexec
service, which is available with
the rsh-server
package and runs as a service through xinetd,
should be disabled.
The rexec
service can be disabled with the following command:
# chkconfig rexec off
The rexec service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Security identifiers
- CCE-27208-8
Result for Disable rsh Service
Result: pass
Rule ID: disable_rsh
Time: 2014-07-14 14:34
Severity: high
The 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:
# chkconfig rsh off
The rsh service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Security identifiers
- CCE-26994-4
Result for Disable rlogin Service
Result: pass
Rule ID: disable_rlogin
Time: 2014-07-14 14:34
Severity: high
The rlogin
service, which is available with
the rsh-server
package and runs as a service through xinetd,
should be disabled.
The rlogin
service can be disabled with the following command:
# chkconfig rlogin off
The rlogin service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Security identifiers
- CCE-26865-6
Result for Uninstall ypserv Package
Result: pass
Rule ID: uninstall_ypserv
Time: 2014-07-14 14:34
Severity: medium
The ypserv
package can be uninstalled with
the following command:
# yum erase ypserv
Removing the ypserv
package decreases the risk of the
accidental (or intentional) activation of NIS or NIS+ services.
Security identifiers
- CCE-27079-3
Remediation script
if rpm -qa | grep -q ypserv; then
yum -y remove ypserv
fi
Result for Disable ypbind Service
Result: pass
Rule ID: disable_ypbind
Time: 2014-07-14 14:34
Severity: medium
The 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:
# chkconfig ypbind off
Disabling the ypbind
service ensures the system is not acting
as a client in a NIS or NIS+ domain.
Security identifiers
- CCE-26894-6
Result for Disable tftp Service
Result: pass
Rule ID: disable_tftp
Time: 2014-07-14 14:34
Severity: medium
The tftp
service should be disabled.
The tftp
service can be disabled with the following command:
# chkconfig tftp off
Disabling the tftp
service ensures the system is not acting
as a TFTP server, which does not provide encryption or authentication.
Security identifiers
- CCE-27055-3
Result for Uninstall tftp-server Package
Result: pass
Rule ID: uninstall_tftp-server
Time: 2014-07-14 14:34
Severity: medium
The tftp-server
package can be removed with the following command:
# yum erase tftp-server
Removing the tftp-server
package decreases the risk of the
accidental (or intentional) activation of tftp services.
Security identifiers
- CCE-26946-4
Result for Ensure tftp Daemon Uses Secure Mode
Result: pass
Rule ID: tftpd_uses_secure_mode
Time: 2014-07-14 14:34
Severity: high
If 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
Using the -s
option causes the TFTP service to only serve files from the
given directory. Serving files from an intentionally-specified directory
reduces the risk of sharing files which should remain private.
Security identifiers
- CCE-27272-4
Result for Disable Automatic Bug Reporting Tool (abrtd)
Result: pass
Rule ID: service_abrtd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig abrtd off
Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the local machine, as well as sensitive information from within a process's address space or registers.
Security identifiers
- CCE-27247-6
Remediation script
#
# Disable abrtd for all run levels
#
chkconfig --level 0123456 abrtd off
#
# Stop abrtd if currently running
#
service abrtd stop
Result for Disable Advanced Configuration and Power Interface (acpid)
Result: pass
Rule ID: service_acpid_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig acpid off
ACPI support is highly desirable for systems in some network roles, such as laptops or desktops. For other systems, such as servers, it may permit accidental or trivially achievable denial of service situations and disabling it is appropriate.
Security identifiers
- CCE-27061-1
Remediation script
#
# Disable acpid for all run levels
#
chkconfig --level 0123456 acpid off
#
# Stop acpid if currently running
#
service acpid stop
Result for Disable Certmonger Service (certmonger)
Result: pass
Rule ID: service_certmonger_disabled
Time: 2014-07-14 14:34
Severity: low
Certmonger 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:
# chkconfig certmonger off
The services provided by certmonger may be essential for systems fulfilling some roles a PKI infrastructure, but its functionality is not necessary for many other use cases.
Security identifiers
- CCE-27267-4
Remediation script
#
# Disable certmonger for all run levels
#
chkconfig --level 0123456 certmonger off
#
# Stop certmonger if currently running
#
service certmonger stop
Result for Disable Control Group Config (cgconfig)
Result: pass
Rule ID: service_cgconfig_disabled
Time: 2014-07-14 14:34
Severity: low
Control 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:
# chkconfig cgconfig off
Unless control groups are used to manage system resources, running the cgconfig service is not necessary.
Security identifiers
- CCE-27250-0
Remediation script
#
# Disable cgconfig for all run levels
#
chkconfig --level 0123456 cgconfig off
#
# Stop cgconfig if currently running
#
service cgconfig stop
Result for Disable CPU Speed (cpuspeed)
Result: pass
Rule ID: service_cpuspeed_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig cpuspeed off
The cpuspeed
service is only necessary if adjusting the CPU clock speed
provides benefit. Traditionally this has included laptops (to enhance battery life),
but may also apply to server or desktop environments where conserving power is
highly desirable or necessary.
Security identifiers
- CCE-26973-8
Remediation script
#
# Disable cpuspeed for all run levels
#
chkconfig --level 0123456 cpuspeed off
#
# Stop cpuspeed if currently running
#
service cpuspeed stop
Result for Disable Hardware Abstraction Layer Service (haldaemon)
Result: pass
Rule ID: service_haldaemon_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig haldaemon off
The haldaemon provides essential functionality on systems that use removable media or devices, but can be disabled for systems that do not require these.
Security identifiers
- CCE-27086-8
Remediation script
#
# Disable haldaemon for all run levels
#
chkconfig --level 0123456 haldaemon off
#
# Stop haldaemon if currently running
#
service haldaemon stop
Result for Disable Software RAID Monitor (mdmonitor)
Result: pass
Rule ID: service_mdmonitor_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig mdmonitor off
If software RAID monitoring is not required, there is no need to run this service.
Security identifiers
- CCE-27193-2
Remediation script
#
# Disable mdmonitor for all run levels
#
chkconfig --level 0123456 mdmonitor off
#
# Stop mdmonitor if currently running
#
service mdmonitor stop
Result for Disable D-Bus IPC Service (messagebus)
Result: pass
Rule ID: service_messagebus_disabled
Time: 2014-07-14 14:34
Severity: low
D-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:
# chkconfig messagebus off
If no services which require D-Bus are needed, then it can be disabled. As a broker for IPC between processes of different privilege levels, it could be a target for attack. However, disabling D-Bus is likely to be impractical for any system which needs to provide a graphical login session.
Security identifiers
- CCE-26913-4
Remediation script
#
# Disable messagebus for all run levels
#
chkconfig --level 0123456 messagebus off
#
# Stop messagebus if currently running
#
service messagebus stop
Result for Disable Network Console (netconsole)
Result: pass
Rule ID: service_netconsole_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig netconsole off
The netconsole
service is not necessary unless there is a need to debug
kernel panics, which is not common.
Security identifiers
- CCE-27254-2
Remediation script
#
# Disable netconsole for all run levels
#
chkconfig --level 0123456 netconsole off
#
# Stop netconsole if currently running
#
service netconsole stop
Result for Disable ntpdate Service (ntpdate)
Result: pass
Rule ID: service_ntpdate_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig ntpdate off
The ntpdate
service may only be suitable for systems which
are rebooted frequently enough that clock drift does not cause problems between
reboots. In any event, the functionality of the ntpdate service is now
available in the ntpd program and should be considered deprecated.
Security identifiers
- CCE-27256-7
Result for Disable Odd Job Daemon (oddjobd)
Result: pass
Rule ID: service_oddjobd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig oddjobd off
The oddjobd
service may provide necessary functionality in
some environments, and can be disabled if it is not needed. Execution of
tasks by privileged programs, on behalf of unprivileged ones, has traditionally
been a source of privilege escalation security issues.
Security identifiers
- CCE-27257-5
Remediation script
#
# Disable oddjobd for all run levels
#
chkconfig --level 0123456 oddjobd off
#
# Stop oddjobd if currently running
#
service oddjobd stop
Result for Disable Portreserve (portreserve)
Result: pass
Rule ID: service_portreserve_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig portreserve off
The portreserve
service provides helpful functionality by
preventing conflicting usage of ports in the reserved port range, but it can be
disabled if not needed.
Security identifiers
- CCE-27258-3
Remediation script
#
# Disable portreserve for all run levels
#
chkconfig --level 0123456 portreserve off
#
# Stop portreserve if currently running
#
service portreserve stop
Result for Enable Process Accounting (psacct)
Result: pass
Rule ID: service_psacct_enabled
Time: 2014-07-14 14:34
Severity: low
The process accounting service, psacct
, works with programs
including acct
and ac
to allow system administrators to view
user activity, such as commands issued by users of the system.
The psacct
service can be enabled with the following command:
# chkconfig --level 2345 psacct on
The psacct
service can provide administrators a convenient
view into some user activities. However, it should be noted that the auditing
system and its audit records provide more authoritative and comprehensive
records.
Security identifiers
- CCE-27259-1
Remediation script
#
# Enable psacct for all run levels
#
chkconfig --level 0123456 psacct on
#
# Start psacct if not currently running
#
service psacct start
Result for Disable Apache Qpid (qpidd)
Result: pass
Rule ID: service_qpidd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig qpidd off
The qpidd service is automatically installed when the "base"
package selection is selected during installation. The qpidd service listens
for network connections, which increases the attack surface of the system. If
the system is not intended to receive AMQP traffic, then the qpidd
service is not needed and should be disabled or removed.
Security identifiers
- CCE-26928-2
Remediation script
#
# Disable qpidd for all run levels
#
chkconfig --level 0123456 qpidd off
#
# Stop qpidd if currently running
#
service qpidd stop
Result for Disable Quota Netlink (quota_nld)
Result: pass
Rule ID: service_quota_nld_disabled
Time: 2014-07-14 14:34
Severity: low
The quota_nld
service provides notifications to
users of disk space quota violations. It listens to the kernel via a netlink
socket for disk quota violations and notifies the appropriate user of the
violation using D-Bus or by sending a message to the terminal that the user has
last accessed.
The quota_nld
service can be disabled with the following command:
# chkconfig quota_nld off
If disk quotas are enforced on the local system, then the
quota_nld
service likely provides useful functionality and should
remain enabled. However, if disk quotas are not used or user notification of
disk quota violation is not desired then there is no need to run this
service.
Security identifiers
- CCE-27260-9
Remediation script
#
# Disable quota_nld for all run levels
#
chkconfig --level 0123456 quota_nld off
#
# Stop quota_nld if currently running
#
service quota_nld stop
Result for Disable Network Router Discovery Daemon (rdisc)
Result: pass
Rule ID: service_rdisc_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig rdisc off
General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.
Security identifiers
- CCE-27261-7
Remediation script
#
# Disable rdisc for all run levels
#
chkconfig --level 0123456 rdisc off
#
# Stop rdisc if currently running
#
service rdisc stop
Result for Disable Red Hat Network Service (rhnsd)
Result: pass
Rule ID: service_rhnsd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig rhnsd off
Although systems management and patching is extremely important to
system security, management by a system outside the enterprise enclave is not
desirable for some environments. However, if the system is being managed by RHN or
RHN Satellite Server the rhnsd
daemon can remain on.
Security identifiers
- CCE-26846-6
Remediation script
#
# Disable rhnsd for all run levels
#
chkconfig --level 0123456 rhnsd off
#
# Stop rhnsd if currently running
#
service rhnsd stop
Result for Disable Red Hat Subscription Manager Daemon (rhsmcertd)
Result: pass
Rule ID: service_rhsmcertd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig rhsmcertd off
The rhsmcertd
service can provide administrators with some
additional control over which of their systems are entitled to particular
subscriptions. However, for systems that are managed locally or which are not
expected to require remote changes to their subscription status, it is
unnecessary and can be disabled.
Security identifiers
- CCE-27262-5
Remediation script
#
# Disable rhsmcertd for all run levels
#
chkconfig --level 0123456 rhsmcertd off
#
# Stop rhsmcertd if currently running
#
service rhsmcertd stop
Result for Disable Cyrus SASL Authentication Daemon (saslauthd)
Result: pass
Rule ID: service_saslauthd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig saslauthd off
The saslauthd
service provides essential functionality for
performing authentication in some directory environments, such as those which
use Kerberos and LDAP. For others, however, in which only local files may be
consulted, it is not necessary and should be disabled.
Security identifiers
- CCE-27263-3
Remediation script
#
# Disable saslauthd for all run levels
#
chkconfig --level 0123456 saslauthd off
#
# Stop saslauthd if currently running
#
service saslauthd stop
Result for Disable SMART Disk Monitoring Service (smartd)
Result: pass
Rule ID: service_smartd_disabled
Time: 2014-07-14 14:34
Severity: low
SMART (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:
# chkconfig smartd off
SMART can help protect against denial of service due to failing hardware. Nevertheless, if it is not needed or the system's drives are not SMART-capable (such as solid state drives), it can be disabled.
Security identifiers
- CCE-26853-2
Remediation script
#
# Disable smartd for all run levels
#
chkconfig --level 0123456 smartd off
#
# Stop smartd if currently running
#
service smartd stop
Result for Disable System Statistics Reset Service (sysstat)
Result: pass
Rule ID: service_sysstat_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig sysstat off
By default the sysstat
service merely runs a program at
boot to reset the statistics, which can be retrieved using programs such as
sar
and sadc
. These may provide useful insight into system
operation, but unless used this service can be disabled.
Security identifiers
- CCE-27265-8
Remediation script
#
# Disable sysstat for all run levels
#
chkconfig --level 0123456 sysstat off
#
# Stop sysstat if currently running
#
service sysstat stop
Result for Enable cron Service
Result: pass
Rule ID: service_crond_enabled
Time: 2014-07-14 14:34
Severity: medium
The 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:
# chkconfig --level 2345 crond on
Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.
Security identifiers
- CCE-27070-2
Remediation script
#
# Enable crond for all run levels
#
chkconfig --level 0123456 crond on
#
# Start crond if not currently running
#
service crond start
Result for Disable anacron Service
Result: notchecked
Rule ID: disable_anacron
Time: 2014-07-14 14:34
Severity: low
The cronie-anacron
package, which provides anacron
functionality, is installed by default.
The cronie-anacron
package can be removed with the following command:
# yum erase cronie-anacron
The anacron
service provides cron
functionality for systems
such as laptops and workstations that may be shut down during the normal times
that cron
jobs are scheduled to run. On systems which do not require this
additional functionality, anacron
could needlessly increase the possible
attack surface for an intruder.
Security identifiers
- CCE-27158-5
Result for Disable At Service (atd)
Result: pass
Rule ID: service_atd_disabled
Time: 2014-07-14 14:34
Severity: low
The 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:
# chkconfig atd off
The atd
service could be used by an unsophisticated insider to carry
out activities outside of a normal login session, which could complicate
accountability. Furthermore, the need to schedule tasks with at
or
batch
is not common.
Security identifiers
- CCE-27249-2
Remediation script
#
# Disable atd for all run levels
#
chkconfig --level 0123456 atd off
#
# Stop atd if currently running
#
service atd stop
Result for Allow Only SSH Protocol 2
Result: pass
Rule ID: sshd_allow_only_protocol2
Time: 2014-07-14 14:34
Severity: high
Only 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
SSH protocol version 1 suffers from design flaws that result in security vulnerabilities and should not be used.
Security identifiers
- CCE-27072-8
Result for Disable SSH Root Login
Result: pass
Rule ID: sshd_disable_root_login
Time: 2014-07-14 14:34
Severity: medium
The 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
Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.
Security identifiers
- CCE-27100-7
Remediation script
grep -q ^PermitRootLogin /etc/ssh/sshd_config && \
sed -i "s/PermitRootLogin.*/PermitRootLogin no/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
echo "PermitRootLogin "no >> /etc/ssh/sshd_config
fi
Result for Use Only Approved Ciphers
Result: pass
Rule ID: sshd_use_approved_ciphers
Time: 2014-07-14 14:34
Severity: medium
Limit 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.
Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.
Security identifiers
- CCE-26555-3
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
Result for Disable X Windows Startup By Setting Runlevel
Result: pass
Rule ID: disable_xwindows_with_runlevel
Time: 2014-07-14 14:34
Severity: low
Setting 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:
Unnecessary services should be disabled to decrease the attack surface of the system.
Security identifiers
- CCE-27119-7
Result for Disable Avahi Server Software
Result: pass
Rule ID: disable_avahi
Time: 2014-07-14 14:34
Severity: low
The avahi-daemon
service can be disabled with the following command:
# chkconfig avahi-daemon off
Because the Avahi daemon service keeps an open network port, it is subject to network attacks. Its functionality is convenient but is only appropriate if the local network can be trusted.
Security identifiers
- CCE-27087-6
Result for Disable the CUPS Service
Result: pass
Rule ID: service_cups_disabled
Time: 2014-07-14 14:34
Severity: low
The cups
service can be disabled with the following command:
# chkconfig cups off
Turn off unneeded services to reduce attack surface.
Security identifiers
- CCE-26899-5
Remediation script
#
# Disable cups for all run levels
#
chkconfig --level 0123456 cups off
#
# Stop cups if currently running
#
service cups stop
Result for Disable Print Server Capabilities
Result: pass
Rule ID: cups_disable_printserver
Time: 2014-07-14 14:34
Severity: low
To prevent remote users from potentially connecting to and using locally configured printers, disable the CUPS print server sharing capabilities. To do so, limit how the server will listen for print jobs by removing the more generic port directive from /etc/cups/cupsd.conf:
Port 631
and replacing it with the Listen
directive:
Listen localhost:631
This will prevent remote users from printing to locally configured printers
while still allowing local users on the machine to print normally.
By default, locally configured printers will not be shared over the network, but if this functionality has somehow been enabled, these recommendations will disable it again. Be sure to disable outgoing printer list broadcasts, or remote users will still be able to see the locally configured printers, even if they cannot actually print to them. To limit print serving to a particular set of users, use the Policy directive.
Security identifiers
- CCE-27107-2
Result for Disable DHCP Service
Result: pass
Rule ID: disable_dhcp_server
Time: 2014-07-14 14:34
Severity: medium
The dhcpd
service should be disabled on
any system that does not need to act as a DHCP server.
The dhcpd
service can be disabled with the following command:
# chkconfig dhcpd off
Unmanaged or unintentionally activated DHCP servers may provide faulty information to clients, interfering with the operation of a legitimate site DHCP server if there is one.
Security identifiers
- CCE-27074-4
Result for Uninstall DHCP Server Package
Result: pass
Rule ID: uninstall_dhcp_server
Time: 2014-07-14 14:34
Severity: medium
If the system does not need to act as a DHCP server,
the dhcp package can be uninstalled.
The dhcp
package can be removed with the following command:
# yum erase dhcp
Removing the DHCP server ensures that it cannot be easily or accidentally reactivated and disrupt network operation.
Security identifiers
- CCE-27120-5
Result for Do Not Use Dynamic DNS
Result: notchecked
Rule ID: dhcp_server_disable_ddns
Time: 2014-07-14 14:34
Severity: low
To 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;
The ddns-update-style option controls only whether the DHCP server will attempt to act as a Dynamic DNS client. As long as the DNS server itself is correctly configured to reject DDNS attempts, an incorrect ddns-update-style setting on the client is harmless (but should be fixed as a best practice).
The Dynamic DNS protocol is used to remotely update the data served by a DNS server. DHCP servers can use Dynamic DNS to publish information about their clients. This setup carries security risks, and its use is not recommended. If Dynamic DNS must be used despite the risks it poses, it is critical that Dynamic DNS transactions be protected using TSIG or some other cryptographic authentication mechanism. See dhcpd.conf(5) for more information about protecting the DHCP server from passing along malicious DNS data from its clients.
Security identifiers
- CCE-27049-6
Result for Deny Decline Messages
Result: notchecked
Rule ID: dhcp_server_deny_decline
Time: 2014-07-14 14:34
Severity: low
Edit /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;
The DHCPDECLINE message can be sent by a DHCP client to indicate that it does not consider the lease offered by the server to be valid. By issuing many DHCPDECLINE messages, a malicious client can exhaust the DHCP server's pool of IP addresses, causing the DHCP server to forget old address allocations.
Security identifiers
- CCE-27106-4
Result for Deny BOOTP Queries
Result: notchecked
Rule ID: dhcp_server_deny_bootp
Time: 2014-07-14 14:34
Severity: low
Unless your network needs to support older BOOTP clients, disable support for the bootp protocol by adding or correcting the global option:
deny bootp;
The bootp option tells dhcpd to respond to BOOTP queries. If support for this simpler protocol is not needed, it should be disabled to remove attack vectors against the DHCP server.
Security identifiers
- CCE-27077-7
Result for Disable DHCP Client
Result: pass
Rule ID: disable_dhcp_client
Time: 2014-07-14 14:34
Severity: low
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
DHCP relies on trusting the local network. If the local network is not trusted, then it should not be used. However, the automatic configuration provided by DHCP is commonly used and the alternative, manual configuration, presents an unacceptable burden in many circumstances.
Security identifiers
- CCE-27021-5
Result for Enable the NTP Daemon
Result: pass
Rule ID: service_ntpd_enabled
Time: 2014-07-14 14:34
Severity: medium
The ntpd
service can be enabled with the following command:
# chkconfig --level 2345 ntpd on
Enabling the ntpd
service ensures that the ntpd
service will be running and that the system will synchronize its time to
any servers specified. This is important whether the system is configured to be
a client (and synchronize only its own clock) or it is also acting as an NTP
server to other systems. Synchronizing time is essential for authentication
services such as Kerberos, but it is also important for maintaining accurate
logs and auditing possible security breaches.
The NTP daemon offers all of the functionality of ntpdate
, which is now
deprecated. Additional information on this is available at
http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate
Security identifiers
- CCE-27093-4
Remediation script
#
# Enable ntpd for all run levels
#
chkconfig --level 0123456 ntpd on
#
# Start ntpd if not currently running
#
service ntpd start
Result for Specify a Remote NTP Server
Result: pass
Rule ID: ntpd_specify_remote_server
Time: 2014-07-14 14:34
Severity: medium
To 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.
Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events.
Security identifiers
- CCE-27098-3
Result for Specify Additional Remote NTP Servers
Result: notchecked
Rule ID: ntpd_specify_multiple_servers
Time: 2014-07-14 14:34
Severity: low
Additional NTP servers can be specified for time synchronization
in the file /etc/ntp.conf
. To do so, add additional lines of the
following form, substituting the IP address or hostname of a remote NTP server for
ntpserver:
server ntpserver
Specifying additional NTP servers increases the availability of accurate time data, in the event that one of the specified servers becomes unavailable. This is typical for a system acting as an NTP server for other systems.
Security identifiers
- CCE-26958-9
Result for Uninstall Sendmail Package
Result: pass
Rule ID: package_sendmail_removed
Time: 2014-07-14 14:34
Severity: medium
Sendmail is not the default mail transfer agent and is
not installed by default.
The sendmail
package can be removed with the following command:
# yum erase sendmail
The sendmail software was not developed with security in mind and its design prevents it from being effectively contained by SELinux. Postfix should be used instead.
Security identifiers
- CCE-27515-6
Result for Disable Postfix Network Listening
Result: pass
Rule ID: postfix_network_listening
Time: 2014-07-14 14:34
Severity: medium
Edit the file /etc/postfix/main.cf
to ensure that only the following
inet_interfaces
line appears:
inet_interfaces = localhost
This ensures postfix
accepts mail messages
(such as cron job reports) from the local system only,
and not from the network, which protects it from network attack.
Security identifiers
- CCE-26780-7
Result for Configure LDAP Client to Use TLS For All Transactions
Result: pass
Rule ID: ldap_client_start_tls
Time: 2014-07-14 14:34
Severity: medium
Configure 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.
The ssl directive specifies whether to use ssl or not. If not specified it will default to no. It should be set to start_tls rather than doing LDAP over SSL.
Security identifiers
- CCE-26690-8
Result for Configure Certificate Directives for LDAP Use of TLS
Result: pass
Rule ID: ldap_client_tls_cacertpath
Time: 2014-07-14 14:34
Severity: medium
Ensure a copy of a trusted CA certificate has been placed in
the file /etc/pki/tls/CA/cacert.pem
. Configure LDAP to enforce TLS
use and to trust certificates signed by that CA. First, edit the file
/etc/pam_ldap.conf
, and add or correct either of the following lines:
tls_cacertdir /etc/pki/tls/CA
or
tls_cacertfile /etc/pki/tls/CA/cacert.pem
Then review the LDAP server and ensure TLS has been configured.
The tls_cacertdir or tls_cacertfile directives are required when tls_checkpeer is configured (which is the default for openldap versions 2.1 and up). These directives define the path to the trust certificates signed by the site CA.
Security identifiers
- CCE-27189-0
Result for Uninstall openldap-servers Package
Result: pass
Rule ID: package_openldap-servers_removed
Time: 2014-07-14 14:34
Severity: low
The openldap-servers
package should be removed if not in use.
Is this machine the OpenLDAP server? If not, remove the package.
# yum erase openldap-servers
The openldap-servers RPM is not installed by default on RHEL 6
machines. It is needed only by the OpenLDAP server, not by the
clients which use LDAP for authentication. If the system is not
intended for use as an LDAP Server it should be removed.
Unnecessary packages should not be installed to decrease the attack surface of the system. While this software is clearly essential on an LDAP server, it is not necessary on typical desktop or workstation systems.
Security identifiers
- CCE-26858-1
Result for Disable DNS Server
Result: pass
Rule ID: disable_dns_server
Time: 2014-07-14 14:34
Severity: low
The named
service can be disabled with the following command:
# chkconfig named off
All network services involve some risk of compromise due to implementation flaws and should be disabled if possible.
Security identifiers
- CCE-26873-0
Result for Uninstall bind Package
Result: pass
Rule ID: uninstall_bind
Time: 2014-07-14 14:34
Severity: low
To remove the bind
package, which contains the
named
service, run the following command:
# yum erase bind
If there is no need to make DNS server software available, removing it provides a safeguard against its activation.
Security identifiers
- CCE-27030-6
Result for Authenticate Zone Transfers
Result: notchecked
Rule ID: dns_server_authenticate_zone_transfers
Time: 2014-07-14 14:34
Severity: low
If it is necessary for a secondary nameserver to receive zone data via zone transfer from the primary server, follow the instructions here. Use dnssec-keygen to create a symmetric key file in the current directory:
# cd /tmp
# dnssec-keygen -a HMAC-MD5 -b 128 -n HOST dns.example.com
Kdns.example.com .+aaa +iiiii
This output is the name of a file containing the new key. Read the file to find
the base64-encoded key string:
# cat Kdns.example.com .+NNN +MMMMM .key
dns.example.com IN KEY 512 3 157 base64-key-string
Add the directives to /etc/named.conf
on the primary server:
key zone-transfer-key {
algorithm hmac-md5;
secret "base64-key-string ";
};
zone "example.com " IN {
type master;
allow-transfer { key zone-transfer-key; };
...
};
Add the directives below to /etc/named.conf
on the secondary nameserver:
key zone-transfer-key {
algorithm hmac-md5;
secret "base64-key-string ";
};
server IP-OF-MASTER {
keys { zone-transfer-key; };
};
zone "example.com " IN {
type slave;
masters { IP-OF-MASTER ; };
...
};
The purpose of the dnssec-keygen command is to create the shared secret string base64-key-string. Once this secret has been obtained and inserted into named.conf on the primary and secondary servers, the key files Kdns.example.com .+NNN +MMMMM .key and Kdns.example.com .+NNN +MMMMM .private are no longer needed, and may safely be deleted.
The BIND transaction signature (TSIG) functionality allows primary and secondary nameservers to use a shared secret to verify authorization to perform zone transfers. This method is more secure than using IP-based limiting to restrict nameserver access, since IP addresses can be easily spoofed. However, if you cannot configure TSIG between your servers because, for instance, the secondary nameserver is not under your control and its administrators are unwilling to configure TSIG, you can configure an allow-transfer directive with numerical IP addresses or ACLs as a last resort.
Security identifiers
- CCE-27496-9
Result for Disable vsftpd Service
Result: pass
Rule ID: disable_vsftpd
Time: 2014-07-14 14:34
Severity: low
The vsftpd
service can be disabled with the following command:
# chkconfig vsftpd off
Running FTP server software provides a network-based avenue of attack, and should be disabled if not needed. Furthermore, the FTP protocol is unencrypted and creates a risk of compromising sensitive information.
Security identifiers
- CCE-26948-0
Remediation script
if service vsftpd status >/dev/null; then
service vsftpd stop
fi
Result for Uninstall vsftpd Package
Result: pass
Rule ID: uninstall_vsftpd
Time: 2014-07-14 14:34
Severity: low
The vsftpd
package can be removed with the following command:
# yum erase vsftpd
Removing the vsftpd package decreases the risk of its accidental activation.
Security identifiers
- CCE-26687-4
Result for Set httpd ServerTokens Directive to Prod
Result: notchecked
Rule ID: httpd_servertokens_prod
Time: 2014-07-14 14:34
Severity: low
ServerTokens 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
Information disclosed to clients about the configuration of the web server and system could be used to plan an attack on the given system. This information disclosure should be restricted to a minimum.
Security identifiers
- CCE-27425-8
Result for Set Permissions on the /var/log/httpd/ Directory
Result: pass
Rule ID: httpd_logs_permissions
Time: 2014-07-14 14:34
Severity: low
Ensure that the permissions on the web server log directory is set to 700:
# chmod 700 /var/log/httpd/
This is its default setting.
Access to the web server's log files may allow an unauthorized user or attacker to access information about the web server or alter the server's log files.
Security identifiers
- CCE-27150-2
Result for Set Permissions on All Configuration Files Inside /etc/httpd/conf/
Result: pass
Rule ID: httpd_conf_files_permissions
Time: 2014-07-14 14:34
Severity: low
Set permissions on the web server configuration files to 640:
# chmod 640 /etc/httpd/conf/*
Access to the web server's configuration files may allow an unauthorized user or attacker to access information about the web server or to alter the server's configuration files.
Security identifiers
- CCE-27316-9