Group
Guide to the Secure Configuration of Oracle Linux 8
Group contains 65 groups and 241 rules |
Group
System Settings
Group contains 42 groups and 202 rules |
[ref]
Contains rules that check correct system settings. |
Group
Installing and Maintaining Software
Group contains 6 groups and 36 rules |
[ref]
The following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
Group
System and Software Integrity
Group contains 2 groups and 2 rules |
[ref]
System and software integrity can be gained by installing antivirus, increasing
system encryption strength with FIPS, verifying installed software, enabling SELinux,
installing an Intrusion Prevention System, etc. However, installing or enabling integrity
checking tools cannot prevent intrusions, but they can detect that an intrusion
may have occurred. Requirements for integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based approaches such
as AIDE may induce considerable overhead in the presence of frequent software updates. |
Group
Software Integrity Checking
Group contains 1 group and 2 rules |
[ref]
Both the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system. |
Group
Verify Integrity with AIDE
Group contains 2 rules |
[ref]
AIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION
. |
Rule
Install AIDE
[ref] | The aide package can be installed with the following command:
$ sudo yum install aide
| Rationale: | The AIDE package must be installed if it is to be available for integrity checking. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_package_aide_installed | References: | cis-csc | 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9 | cjis | 5.10.1.3 | cobit5 | APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06 | disa | CCI-002696, CCI-001744 | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4 | isa-62443-2013 | SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6 | ism | 1034, 1288, 1341, 1417 | iso27001-2013 | A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3 | nist | CM-6(a) | nist-csf | DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3 | pcidss | Req-11.5 | os-srg | SRG-OS-000445-GPOS-00199 | stigid | OL08-00-010359 | anssi | R76, R79 | pcidss4 | 11.5.2 | stigref | SV-252654r958944_rule |
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Rule
Build and Test AIDE Database
[ref] | Run the following command to generate a new database:
$ sudo /usr/sbin/aide --init
By default, the database will be written to the file
/var/lib/aide/aide.db.new.gz .
Storing the database, the configuration file /etc/aide.conf , and the binary
/usr/sbin/aide
(or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity.
The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
$ sudo /usr/sbin/aide --check
If this check produces any unexpected output, investigate. | Rationale: | 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. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_aide_build_database | References: | cis-csc | 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9 | cjis | 5.10.1.3 | cobit5 | APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06 | disa | CCI-002696, CCI-001744 | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4 | isa-62443-2013 | SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6 | iso27001-2013 | A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3 | nist | CM-6(a) | nist-csf | DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3 | pcidss | Req-11.5 | os-srg | SRG-OS-000445-GPOS-00199 | stigid | OL08-00-010359 | anssi | R76, R79 | pcidss4 | 11.5.2 | stigref | SV-252654r958944_rule |
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Group
Disk Partitioning
Group contains 9 rules |
[ref]
To ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/ , /boot , and swap .
- If starting with any of the default layouts, check the box to
\"Review and modify partitioning.\" This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making
/ 's logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later. - If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning
scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible. |
Rule
Ensure /boot Located On Separate Partition
[ref] | It is recommended that the /boot directory resides on a separate
partition. This makes it easier to apply restrictions e.g. through the
noexec mount option. Eventually, the /boot partition can
be configured not to be mounted automatically with the noauto mount
option. | Rationale: | The /boot partition contains the kernel and bootloader files.
Access to this partition should be restricted. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_boot | References: | | |
|
Rule
Ensure /home Located On Separate Partition
[ref] | If user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. | Rationale: | Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_home | References: | cis-csc | 12, 15, 8 | cobit5 | APO13.01, DSS05.02 | disa | CCI-000366 | isa-62443-2013 | SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.13.1.1, A.13.2.1, A.14.1.3 | nist | CM-6(a), SC-5(2) | nist-csf | PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | stigid | OL08-00-010800 | anssi | R28 | stigref | SV-248648r991589_rule |
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Rule
Ensure /opt Located On Separate Partition
[ref] | It is recommended that the /opt directory resides on a separate
partition. | Rationale: | The /opt partition contains additional software, usually installed
outside the packaging system. Putting this directory on a separate partition
makes it easier to apply restrictions e.g. through the nosuid mount
option. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_opt | References: | | |
|
Rule
Ensure /srv Located On Separate Partition
[ref] | If a file server (FTP, TFTP...) is hosted locally, create a separate partition
for /srv at installation time (or migrate it later using LVM). If
/srv will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. | Rationale: | Srv deserves files for local network file server such as FTP. Ensuring
that /srv is mounted on its own partition enables the setting of
more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. | Severity: | unknown | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_srv | References: | | |
|
Rule
Ensure /usr Located On Separate Partition
[ref] | It is recommended that the /usr directory resides on a separate
partition. | Rationale: | The /usr partition contains system software, utilities and files.
Putting it on a separate partition allows limiting its size and applying
restrictions through mount options. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_usr | References: | | |
|
Rule
Ensure /var Located On Separate Partition
[ref] | The /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM. | Rationale: | Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var | References: | cis-csc | 12, 15, 8 | cobit5 | APO13.01, DSS05.02 | disa | CCI-000366 | isa-62443-2013 | SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.13.1.1, A.13.2.1, A.14.1.3 | nist | CM-6(a), SC-5(2) | nist-csf | PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | stigid | OL08-00-010540 | anssi | R28 | stigref | SV-248608r991589_rule |
| |
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Rule
Ensure /var/log Located On Separate Partition
[ref] | System logs are stored in the /var/log directory.
Ensure that /var/log has its own partition or logical
volume at installation time, or migrate it using LVM. | Rationale: | Placing /var/log in its own partition
enables better separation between log files
and other files in /var/ . | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var_log | References: | cis-csc | 1, 12, 14, 15, 16, 3, 5, 6, 8 | cobit5 | APO11.04, APO13.01, BAI03.05, DSS05.02, DSS05.04, DSS05.07, MEA02.01 | disa | CCI-000366 | isa-62443-2009 | 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4 | isa-62443-2013 | SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3 | nerc-cip | CIP-007-3 R6.5 | nist | CM-6(a), AU-4, SC-5(2) | nist-csf | PR.PT-1, PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | stigid | OL08-00-010541 | anssi | R28 | stigref | SV-248609r991589_rule |
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Rule
Ensure /var/tmp Located On Separate Partition
[ref] | The /var/tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM. | Rationale: | The /var/tmp partition is used as temporary storage by many programs.
Placing /var/tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var_tmp | References: | | |
|
Rule
Ensure tmp.mount Unit Is Enabled
[ref] | The /tmp directory is a world-writable directory used
for temporary file storage. This directory is managed by systemd-tmpfiles .
Ensure that the tmp.mount systemd unit is enabled. | Rationale: | The /tmp directory is used as temporary storage by many programs.
Placing /tmp in a tmpfs filesystem enables the setting of more
restrictive mount options, which can help protect programs which use it.
The tmp.mount unit configures the tmpfs filesystem and ensures
the /tmp directory is wiped during reboot. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_systemd_tmp_mount_enabled | References: | | |
|
Group
Sudo
Group contains 16 rules |
[ref]
Sudo , which stands for "su 'do'", provides the ability to delegate authority
to certain users, groups of users, or system administrators. When configured for system
users and/or groups, Sudo can allow a user or group to execute privileged commands
that normally only root is allowed to execute.
For more information on Sudo and addition Sudo configuration options, see
https://www.sudo.ws. |
Rule
Install sudo Package
[ref] | The sudo package can be installed with the following command:
$ sudo yum install sudo
| Rationale: | sudo is a program designed to allow a system administrator to give
limited root privileges to users and log root activity. The basic philosophy
is to give as few privileges as possible but still allow system users to
get their work done.
| Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_package_sudo_installed | References: | | |
|
Rule
Verify Group Who Owns /etc/sudoers.d Directory
[ref] | To properly set the group owner of /etc/sudoers.d , run the command: $ sudo chgrp root /etc/sudoers.d
| Rationale: | The ownership of the /etc/sudoers.d directory by the root group is important
because this directory hosts sudo configuration. Protection of this
directory is critical for system security. Assigning the ownership to root
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_groupowner_etc_sudoersd | References: | | |
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Rule
Verify User Who Owns /etc/sudoers.d Directory
[ref] | To properly set the owner of /etc/sudoers.d , run the command: $ sudo chown root /etc/sudoers.d
| Rationale: | The ownership of the /etc/sudoers.d directory by the root user is important
because this directory hosts sudo configuration. Protection of this
directory is critical for system security. Assigning the ownership to root
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_owner_etc_sudoersd | References: | | |
|
Rule
Verify Permissions On /etc/sudoers.d Directory
[ref] | To properly set the permissions of /etc/sudoers.d , run the command: $ sudo chmod 0750 /etc/sudoers.d
| Rationale: | Setting correct permissions on the /etc/sudoers.d directory is important
because this directory hosts sudo configuration. Protection of this
directory is critical for system security. Restricting the permissions
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_permissions_etc_sudoersd | References: | | |
|
Rule
Verify Group Who Owns /etc/sudoers File
[ref] | To properly set the group owner of /etc/sudoers , run the command: $ sudo chgrp root /etc/sudoers
| Rationale: | The ownership of the /etc/sudoers file by the root group is important
because this file hosts sudo configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_sudoers | References: | | |
|
Rule
Verify User Who Owns /etc/sudoers File
[ref] | To properly set the owner of /etc/sudoers , run the command: $ sudo chown root /etc/sudoers
| Rationale: | The ownership of the /etc/sudoers file by the root user is important
because this file hosts sudo configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_sudoers | References: | | |
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Rule
Verify Permissions On /etc/sudoers File
[ref] | To properly set the permissions of /etc/sudoers , run the command: $ sudo chmod 0440 /etc/sudoers
| Rationale: | Setting correct permissions on the /etc/sudoers file is important
because this file hosts sudo configuration. Protection of this
file is critical for system security. Restricting the permissions
ensures exclusive control of the sudo configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_sudoers | References: | | |
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Rule
Ensure sudo Runs In A Minimal Environment - sudo env_reset
[ref] | The sudo env_reset tag, when specified, will run the command in a minimal environment,
containing the TERM, PATH, HOME, MAIL, SHELL, LOGNAME, USER and SUDO_* variables.
On Oracle Linux 8, env_reset is enabled by default
This should be enabled by making sure that the env_reset tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | Forcing sudo to reset the environment ensures that environment variables are not passed on to the
command accidentaly, preventing leak of potentially sensitive information. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_env_reset | References: | | |
|
Rule
Ensure sudo Ignores Commands In Current Dir - sudo ignore_dot
[ref] | The sudo ignore_dot tag, when specified, will ignore the current directory
in the PATH environment variable.
On Oracle Linux 8, ignore_dot is enabled by default
This should be enabled by making sure that the ignore_dot tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | Ignoring the commands in the user's current directory prevents an attacker from executing commands
downloaded locally. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_ignore_dot | References: | | |
|
Rule
Ensure Privileged Escalated Commands Cannot Execute Other Commands - sudo NOEXEC
[ref] | The sudo NOEXEC tag, when specified, prevents user executed
commands from executing other commands, like a shell for example.
This should be enabled by making sure that the NOEXEC tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | Restricting the capability of sudo allowed commands to execute sub-commands
prevents users from running programs with privileges they wouldn't have otherwise. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_noexec | References: | | |
|
Rule
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo requiretty
[ref] | The sudo requiretty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the requiretty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | Restricting the use cases in which a user is allowed to execute sudo commands
reduces the attack surface. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_requiretty | References: | | |
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Rule
Ensure sudo umask is appropriate - sudo umask
[ref] | The sudo umask tag, when specified, will be added the to the user's umask in the
command environment.
On Oracle Linux 8, the default umask value is 0022.
The umask should be configured by making sure that the umask=0077
tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read or
written to by unauthorized users. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_umask | References: | | |
|
Rule
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty
[ref] | The sudo use_pty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the use_pty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . | Rationale: | Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining
access to the user's terminal after the main program has finished executing. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudo_add_use_pty | References: | | |
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Rule
Explicit arguments in sudo specifications
[ref] | All commands in the sudoers file must strictly specify the arguments allowed to be used for a given user.
If the command is supposed to be executed only without arguments, pass "" as an argument in the corresponding user specification. Warning:
This rule doesn't come with a remediation, as absence of arguments in the user spec doesn't mean that the command is intended to be executed with no arguments. Warning:
The rule can produce false findings when an argument contains a comma - sudoers syntax allows comma escaping using backslash, but the check doesn't support that. For example, root ALL=(ALL) echo 1\,2 allows root to execute echo 1,2 , but the check would interpret it as two commands echo 1\ and 2 . | Rationale: | Any argument can modify quite significantly the behavior of a program, whether regarding the
realized operation (read, write, delete, etc.) or accessed resources (path in a file system tree). To
avoid any possibility of misuse of a command by a user, the ambiguities must be removed at the
level of its specification.
For example, on some systems, the kernel messages are only accessible by root.
If a user nevertheless must have the privileges to read them, the argument of the dmesg command has to be restricted
in order to prevent the user from flushing the buffer through the -c option:
user ALL = dmesg ""
| Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudoers_explicit_command_args | References: | | |
|
Rule
Don't define allowed commands in sudoers by means of exclusion
[ref] | Policies applied by sudo through the sudoers file should not involve negation.
Each user specification in the sudoers file contains a comma-delimited list of command specifications.
The definition can make use glob patterns, as well as of negations.
Indirect definition of those commands by means of exclusion of a set of commands is trivial to bypass, so it is not allowed to use such constructs. Warning:
This rule doesn't come with a remediation, as negations indicate design issues with the sudoers user specifications design. Just removing negations doesn't increase the security - you typically have to rethink the definition of allowed commands to fix the issue. | Rationale: | Specifying access right using negation is inefficient and can be easily circumvented.
For example, it is expected that a specification like
# To avoid absolutely , this rule can be easily circumvented!
user ALL = ALL ,!/ bin/sh
prevents the execution of the shell
but that’s not the case: just copy the binary /bin/sh to a different name to make it executable
again through the rule keyword ALL . | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudoers_no_command_negation | References: | | |
|
Rule
Don't target root user in the sudoers file
[ref] | The targeted users of a user specification should be, as much as possible, non privileged users (i.e.: non-root).
User specifications have to explicitly list the runas spec (i.e. the list of target users that can be impersonated), and ALL or root should not be used. Warning:
This rule doesn't come with a remediation, as the exact requirement allows exceptions, and removing lines from the sudoers file can make the system non-administrable. | Rationale: | It is common that the command to be executed does not require superuser rights (editing a file
whose the owner is not root, sending a signal to an unprivileged process,etc.). In order to limit
any attempt of privilege escalation through a command, it is better to apply normal user rights. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_sudoers_no_root_target | References: | | |
|
Group
Updating Software
Group contains 9 rules |
[ref]
The yum command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
Oracle Linux 8 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
yum or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
Rule
Install dnf-automatic Package
[ref] | The dnf-automatic package can be installed with the following command:
$ sudo yum install dnf-automatic
| Rationale: | dnf-automatic is an alternative command line interface (CLI)
to dnf upgrade suitable for automatic, regular execution.
| Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_package_dnf-automatic_installed | References: | | |
|
Rule
Configure dnf-automatic to Install Available Updates Automatically
[ref] | To ensure that the packages comprising the available updates will be automatically installed by dnf-automatic , set apply_updates to yes under [commands] section in /etc/dnf/automatic.conf . | Rationale: | Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise.
The automated installation of updates ensures that recent security patches
are applied in a timely manner. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_dnf-automatic_apply_updates | References: | ism | 0940, 1144, 1467, 1472, 1483, 1493, 1494, 1495 | nist | SI-2(5), CM-6(a), SI-2(c) | ospp | FMT_SMF_EXT.1 | os-srg | SRG-OS-000805-GPOS-00260 | anssi | R61 |
| |
|
Rule
Configure dnf-automatic to Install Only Security Updates
[ref] | To configure dnf-automatic to install only security updates
automatically, set upgrade_type to security under
[commands] section in /etc/dnf/automatic.conf . | Rationale: | By default, dnf-automatic installs all available updates.
Reducing the amount of updated packages only to updates that were
issued as a part of a security advisory increases the system stability. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_dnf-automatic_security_updates_only | References: | | |
|
Rule
Ensure gpgcheck Enabled In Main yum Configuration
[ref] | The gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure yum to check package signatures before installing
them, ensure the following line appears in /etc/yum.conf in
the [main] section:
gpgcheck=1
| Rationale: | Changes to any software components can have significant effects on the
overall security of the operating system. This requirement ensures the
software has not been tampered with and that it has been provided by a
trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
Verifying the authenticity of the software prior to installation
validates the integrity of the patch or upgrade received from a vendor.
This ensures the software has not been tampered with and that it has been
provided by a trusted vendor. Self-signed certificates are disallowed by
this requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA). | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated | References: | cis-csc | 11, 2, 3, 9 | cjis | 5.10.4.1 | cobit5 | APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02 | cui | 3.4.8 | disa | CCI-003992 | hipaa | 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i) | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4 | isa-62443-2013 | SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6 | iso27001-2013 | A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4 | nist | CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b) | nist-csf | PR.DS-6, PR.DS-8, PR.IP-1 | ospp | FPT_TUD_EXT.1, FPT_TUD_EXT.2 | pcidss | Req-6.2 | os-srg | SRG-OS-000366-GPOS-00153 | stigid | OL08-00-010370 | anssi | R59 | pcidss4 | 6.3.3, 6.3 | stigref | SV-248574r1015031_rule |
| |
|
Rule
Ensure gpgcheck Enabled for Local Packages
[ref] | yum should be configured to verify the signature(s) of local packages
prior to installation. To configure yum to verify signatures of local
packages, set the localpkg_gpgcheck to 1 in /etc/yum.conf .
| Rationale: | Changes to any software components can have significant effects to the overall security
of the operating system. This requirement ensures the software has not been tampered and
has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must
be signed with a certificate recognized and approved by the organization. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_local_packages | References: | cis-csc | 11, 3, 9 | cobit5 | BAI10.01, BAI10.02, BAI10.03, BAI10.05 | cui | 3.4.8 | disa | CCI-003992 | hipaa | 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i) | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3 | isa-62443-2013 | SR 7.6 | iso27001-2013 | A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4 | nist | CM-11(a), CM-11(b), CM-6(a), CM-5(3), SA-12, SA-12(10) | nist-csf | PR.IP-1 | ospp | FPT_TUD_EXT.1, FPT_TUD_EXT.2 | os-srg | SRG-OS-000366-GPOS-00153 | stigid | OL08-00-010371 | anssi | R59 | stigref | SV-248575r1015032_rule |
| |
|
Rule
Ensure gpgcheck Enabled for All yum Package Repositories
[ref] | To ensure signature checking is not disabled for
any repos, remove any lines from files in /etc/yum.repos.d of the form:
gpgcheck=0
| Rationale: | Verifying the authenticity of the software prior to installation validates
the integrity of the patch or upgrade received from a vendor. This ensures
the software has not been tampered with and that it has been provided by a
trusted vendor. Self-signed certificates are disallowed by this
requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA)." | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled | References: | cis-csc | 11, 2, 3, 9 | cjis | 5.10.4.1 | cobit5 | APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02 | cui | 3.4.8 | disa | CCI-003992 | hipaa | 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i) | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4 | isa-62443-2013 | SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6 | iso27001-2013 | A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4 | nist | CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b) | nist-csf | PR.DS-6, PR.DS-8, PR.IP-1 | ospp | FPT_TUD_EXT.1, FPT_TUD_EXT.2 | pcidss | Req-6.2 | os-srg | SRG-OS-000366-GPOS-00153 | stigid | OL08-00-010370 | anssi | R59 | pcidss4 | 6.3.3, 6.3 | stigref | SV-248574r1015031_rule |
| |
|
Rule
Ensure Oracle Linux GPG Key Installed
[ref] | To ensure the system can cryptographically verify base software
packages come from Oracle (and to connect to the Unbreakable Linux Network to
receive them), the Oracle GPG key must properly be installed.
To install the Oracle GPG key, run:
$ sudo uln_register
If the system is not connected to the Internet,
then install the Oracle GPG key from trusted media such as
the Oracle installation CD-ROM or DVD. Assuming the disc is mounted
in /media/cdrom , use the following command as the root user to import
it into the keyring:
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY-oracle
Alternatively, the key may be pre-loaded during the Oracle installation. In
such cases, the key can be installed by running the following command:
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
| Rationale: | Changes to software components can have significant effects on the
overall security of the operating system. This requirement ensures
the software has not been tampered with and that it has been provided
by a trusted vendor. The Oracle GPG key is necessary to
cryptographically verify packages are from Oracle. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_ensure_oracle_gpgkey_installed | References: | cis-csc | 11, 2, 3, 9 | cobit5 | APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02 | disa | CCI-001749 | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4 | isa-62443-2013 | SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6 | iso27001-2013 | A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4 | nist | CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), CM-11(a), CM-11(b) | nist-csf | PR.DS-6, PR.DS-8, PR.IP-1 | pcidss | Req-6.2 | stigid | OL08-00-010019 | cis | 1.2.2 | anssi | R59 | stigref | SV-256978r1015073_rule |
| |
|
Rule
Ensure Software Patches Installed
[ref] |
If the system is joined to the ULN
or a yum server, run the following command to install updates:
$ sudo yum update
If the system is not configured to use one of these sources, updates (in the form of RPM packages)
can be manually downloaded from the ULN and installed using rpm .
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates. Warning:
The OVAL feed of Oracle Linux 8 is not a XML file, which may not be understood by all scanners. | Rationale: | Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_security_patches_up_to_date | References: | cis-csc | 18, 20, 4 | cjis | 5.10.4.1 | cobit5 | APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02 | disa | CCI-000366 | isa-62443-2009 | 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9 | iso27001-2013 | A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3 | nist | SI-2(5), SI-2(c), CM-6(a) | nist-csf | ID.RA-1, PR.IP-12 | ospp | FMT_MOF_EXT.1 | pcidss | Req-6.2 | os-srg | SRG-OS-000480-GPOS-00227 | stigid | OL08-00-010010 | anssi | R61 | pcidss4 | 6.3.3, 6.3 | stigref | SV-248523r991589_rule |
| |
|
Rule
Enable dnf-automatic Timer
[ref] |
The dnf-automatic timer can be enabled with the following command:
$ sudo systemctl enable dnf-automatic.timer
| Rationale: | The dnf-automatic is an alternative command line interface (CLI) to dnf upgrade with specific facilities to make it suitable to be executed automatically and regularly from systemd timers, cron jobs and similar.
The tool is controlled by dnf-automatic.timer SystemD timer. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_timer_dnf-automatic_enabled | References: | | |
|
Group
Account and Access Control
Group contains 11 groups and 30 rules |
[ref]
In traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
Oracle Linux 8. |
Group
Protect Accounts by Configuring PAM
Group contains 4 groups and 14 rules |
[ref]
PAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth . This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. Warning:
Be careful when making changes to PAM's configuration files.
The syntax for these files is complex, and modifications can
have unexpected consequences. The default configurations shipped
with applications should be sufficient for most users. |
Group
Set Lockouts for Failed Password Attempts
Group contains 5 rules |
[ref]
The pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock .
Warning:
Locking out user accounts presents the
risk of a denial-of-service attack. The lockout policy
must weigh whether the risk of such a
denial-of-service attack outweighs the benefits of thwarting
password guessing attacks. |
Rule
Limit Password Reuse
[ref] | Do not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_unix or pam_pwhistory PAM modules. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report. Warning:
Newer versions of authselect contain an authselect feature to easily and properly
enable pam_pwhistory.so module. If this feature is not yet available in your
system, an authselect custom profile must be used to avoid integrity issues in PAM files. | Rationale: | Preventing re-use of previous passwords helps ensure that a compromised password is not
re-used by a user. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_unix_remember | References: | cis-csc | 1, 12, 15, 16, 5 | cjis | 5.6.2.1.1 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | cui | 3.5.8 | disa | CCI-000200 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(f), IA-5(1)(e) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | pcidss | Req-8.2.5 | os-srg | SRG-OS-000077-GPOS-00045 | anssi | R31 | pcidss4 | 8.3.7, 8.3 |
| |
|
Rule
Lock Accounts After Failed Password Attempts
[ref] | This rule configures the system to lock out accounts after a number of incorrect login attempts
using pam_faillock.so .
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected.
Ensure that the file /etc/security/faillock.conf contains the following entry:
deny = <count>
Where count should be less than or equal to
3 and greater than 0.
In order to avoid errors when manually editing these files, it is
recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny | References: | cis-csc | 1, 12, 15, 16 | cjis | 5.5.3 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | cui | 3.1.8 | disa | CCI-000044, CCI-002238 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(a) | nist-csf | PR.AC-7 | ospp | FIA_AFL.1 | pcidss | Req-8.1.6 | os-srg | SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 | stigid | OL08-00-020010, OL08-00-020011 | anssi | R31 | pcidss4 | 8.3.4, 8.3 | stigref | SV-248652r958388_rule, SV-248653r958388_rule |
| |
|
Rule
Configure the root Account for Failed Password Attempts
[ref] | This rule configures the system to lock out the root account after a number of
incorrect login attempts using pam_faillock.so .
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid errors when manually editing these files, it is
recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny_root | References: | cis-csc | 1, 12, 15, 16 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | disa | CCI-000044, CCI-002238 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(b), IA-5(c) | nist-csf | PR.AC-7 | os-srg | SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 | stigid | OL08-00-020022, OL08-00-020023 | anssi | R31 | stigref | SV-248664r958388_rule, SV-248665r958388_rule |
| |
|
Rule
Set Interval For Counting Failed Password Attempts
[ref] | Utilizing pam_faillock.so , the fail_interval directive configures the system
to lock out an account after a number of incorrect login attempts within a specified time
period.
Ensure that the file /etc/security/faillock.conf contains the following entry:
fail_interval = <interval-in-seconds> where interval-in-seconds is 900 or greater.
In order to avoid errors when manually editing these files, it is
recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, otherwise known as brute-forcing, is reduced.
Limits are imposed by locking the account. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_interval | References: | cis-csc | 1, 12, 15, 16 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | disa | CCI-000044, CCI-002238 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(a) | nist-csf | PR.AC-7 | ospp | FIA_AFL.1 | os-srg | SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 | stigid | OL08-00-020012, OL08-00-020013 | anssi | R31 | stigref | SV-248654r958388_rule, SV-248655r958388_rule |
| |
|
Rule
Set Lockout Time for Failed Password Attempts
[ref] | This rule configures the system to lock out accounts during a specified time period after a
number of incorrect login attempts using pam_faillock.so .
Ensure that the file /etc/security/faillock.conf contains the following entry:
unlock_time=<interval-in-seconds> where
interval-in-seconds is 900 or greater.
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid any errors when manually editing these files,
it is recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version.
If unlock_time is set to 0 , manual intervention by an administrator is required
to unlock a user. This should be done using the faillock tool. Warning:
If the system supports the new /etc/security/faillock.conf file but the
pam_faillock.so parameters are defined directly in /etc/pam.d/system-auth and
/etc/pam.d/password-auth , the remediation will migrate the unlock_time parameter
to /etc/security/faillock.conf to ensure compatibility with authselect tool.
The parameters deny and fail_interval , if used, also have to be migrated
by their respective remediation. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, otherwise known as brute-forcing, is reduced.
Limits are imposed by locking the account. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_unlock_time | References: | cis-csc | 1, 12, 15, 16 | cjis | 5.5.3 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | cui | 3.1.8 | disa | CCI-000044, CCI-002238 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(b) | nist-csf | PR.AC-7 | ospp | FIA_AFL.1 | pcidss | Req-8.1.7 | os-srg | SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 | stigid | OL08-00-020014, OL08-00-020015 | anssi | R31 | pcidss4 | 8.3.4, 8.3 | stigref | SV-248656r958388_rule, SV-248657r958388_rule |
| |
|
Group
Set Password Quality Requirements
Group contains 1 group and 7 rules |
[ref]
The default pam_pwquality PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes. The
pam_pwquality module is the preferred way of configuring
password requirements.
The man pages pam_pwquality(8)
provide information on the capabilities and configuration of
each. |
Group
Set Password Quality Requirements with pam_pwquality
Group contains 7 rules |
[ref]
The pam_pwquality PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_pwquality to require at least one uppercase
character, lowercase character, digit, and other (special)
character, make sure that pam_pwquality exists in /etc/pam.d/system-auth :
password requisite pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth .
Next, modify the settings in /etc/security/pwquality.conf to match the following:
difok = 4
minlen = 14
dcredit = -1
ucredit = -1
lcredit = -1
ocredit = -1
maxrepeat = 3
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows. |
Rule
Ensure PAM Enforces Password Requirements - Minimum Digit Characters
[ref] | The pam_pwquality 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_pwquality will grant +1 additional
length credit for each digit. Modify the dcredit setting in
/etc/security/pwquality.conf to require the use of a digit in passwords. | Rationale: | Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring digits makes password guessing attacks more difficult by ensuring a larger
search space. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_dcredit | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | ospp | FMT_SMF_EXT.1 | pcidss | Req-8.2.3 | os-srg | SRG-OS-000071-GPOS-00039 | stigid | OL08-00-020130 | anssi | R31 | pcidss4 | 8.3.6, 8.3 | stigref | SV-248689r1015049_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
[ref] | The pam_pwquality 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_pwquality will grant +1 additional
length credit for each lowercase character. Modify the lcredit setting in
/etc/security/pwquality.conf to require the use of a lowercase character in passwords. | Rationale: | Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possble combinations that need to be tested before the password is compromised.
Requiring a minimum number of lowercase characters makes password guessing attacks
more difficult by ensuring a larger search space. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_lcredit | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | ospp | FMT_SMF_EXT.1 | pcidss | Req-8.2.3 | os-srg | SRG-OS-000070-GPOS-00038 | stigid | OL08-00-020120 | anssi | R31 | pcidss4 | 8.3.6, 8.3 | stigref | SV-248688r1015048_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Minimum Different Categories
[ref] | The pam_pwquality module's minclass parameter controls
requirements for usage of different character classes, or types, of character
that must exist in a password before it is considered valid. For example,
setting this value to three (3) requires that any password must have characters
from at least three different categories in order to be approved. The default
value is zero (0), meaning there are no required classes. There are four
categories available:
* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)
Modify the minclass setting in /etc/security/pwquality.conf entry
to require 4
differing categories of characters when changing passwords. | Rationale: | Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The
more complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised.
Requiring a minimum number of character categories makes password guessing attacks more difficult
by ensuring a larger search space. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_minclass | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | os-srg | SRG-OS-000072-GPOS-00040 | stigid | OL08-00-020160 | anssi | R68 | stigref | SV-248692r1015052_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Minimum Length
[ref] | The pam_pwquality module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=15
after pam_pwquality to set minimum password length requirements. | Rationale: | The shorter the password, the lower the number of possible combinations
that need to be tested before the password is compromised.
Password complexity, or strength, is a measure of the effectiveness of a
password in resisting attempts at guessing and brute-force attacks.
Password length is one factor of several that helps to determine strength
and how long it takes to crack a password. Use of more characters in a password
helps to exponentially increase the time and/or resources required to
compromise the password. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_minlen | References: | cis-csc | 1, 12, 15, 16, 5 | cjis | 5.6.2.1.1 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | ospp | FMT_SMF_EXT.1 | pcidss | Req-8.2.3 | os-srg | SRG-OS-000078-GPOS-00046 | stigid | OL08-00-020230 | anssi | R31, R68 | pcidss4 | 8.3.6, 8.3 | stigref | SV-248699r1015058_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Minimum Special Characters
[ref] | The pam_pwquality 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_pwquality will grant +1
additional length credit for each special character. Modify the ocredit setting
in /etc/security/pwquality.conf to equal -1
to require use of a special character in passwords. | Rationale: | Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring a minimum number of special characters makes password guessing attacks
more difficult by ensuring a larger search space. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_ocredit | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | ospp | FMT_SMF_EXT.1 | os-srg | SRG-OS-000266-GPOS-00101 | stigid | OL08-00-020280 | anssi | R31 | stigref | SV-248709r1015063_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session
[ref] | To configure the number of retry prompts that are permitted per-session:
Edit the /etc/security/pwquality.conf to include
retry=3
, or a lower value if site
policy is more restrictive. The DoD requirement is a maximum of 3 prompts
per session. | Rationale: | 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. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_retry | References: | cis-csc | 1, 11, 12, 15, 16, 3, 5, 9 | cjis | 5.5.3 | cobit5 | BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 7.6 | iso27001-2013 | A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7, PR.IP-1 | os-srg | SRG-OS-000069-GPOS-00037, SRG-OS-000480-GPOS-00227 | stigid | OL08-00-020102, OL08-00-020103, OL08-00-020104 | anssi | R68 | stigref | SV-252658r991589_rule, SV-252659r991589_rule, SV-252660r991589_rule |
| |
|
Rule
Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
[ref] | The pam_pwquality 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_pwquality will grant +1 additional
length credit for each uppercase character. Modify the ucredit setting in
/etc/security/pwquality.conf to require the use of an uppercase character in passwords. | Rationale: | Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more
complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_ucredit | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | ospp | FMT_SMF_EXT.1 | pcidss | Req-8.2.3 | os-srg | SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038 | stigid | OL08-00-020110 | anssi | R31 | stigref | SV-248687r1015047_rule |
| |
|
Group
Set Password Hashing Algorithm
Group contains 1 rule |
[ref]
The system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
Rule
Set PAM''s Password Hashing Algorithm
[ref] | The PAM system service can be configured to only store encrypted representations of passwords.
In "/etc/pam.d/system-auth", the password section of the file controls which
PAM modules to execute during a password change.
Set the pam_unix.so module in the password section to include the option
sha512 and no other hashing
algorithms as shown below:
password sufficient pam_unix.so sha512
other arguments...
This will help ensure that new passwords for local users will be stored using the
sha512 algorithm. Warning:
The hashing algorithms to be used with pam_unix.so are defined with independent module
options. There are at least 7 possible algorithms and likely more algorithms will be
introduced along the time. Due the the number of options and its possible combinations,
the use of multiple hashing algorithm options may bring unexpected behaviors to the
system. For this reason the check will pass only when one hashing algorithm option is
defined and is aligned to the "var_password_hashing_algorithm_pam" variable. The
remediation will ensure the correct option and remove any other extra hashing algorithm
option. | Rationale: | Passwords need to be protected at all times, and encryption is the standard method for
protecting passwords. If passwords are not encrypted, they can be plainly read
(i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm
are no more protected than if they are kept in plain text.
This setting ensures user and group account administration utilities are configured to store
only encrypted representations of passwords. Additionally, the crypt_style
configuration option in /etc/libuser.conf ensures the use of a strong hashing
algorithm that makes password cracking attacks more difficult. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_systemauth | References: | cis-csc | 1, 12, 15, 16, 5 | cjis | 5.6.2.2 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | cui | 3.13.11 | disa | CCI-000196, CCI-000803, CCI-004062 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0418, 1055, 1402 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(c), IA-5(1)(c), CM-6(a) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | pcidss | Req-8.2.1 | os-srg | SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061 | stigid | OL08-00-010159 | anssi | R68 | pcidss4 | 8.3.2, 8.3 | stigref | SV-248543r971535_rule |
| |
|
Rule
Set Up a Private Namespace in PAM Configuration
[ref] | To setup a private namespace add the following line to /etc/pam.d/login :
session required pam_namespace.so
| Rationale: | The pam_namespace PAM module sets up a private namespace for a
session with polyinstantiated directories. A polyinstantiated directory
provides a different instance of itself based on user name, or when using
SELinux, user name, security context or both. The polyinstatied directories
can be used to dedicate separate temporary directories to each account. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_enable_pam_namespace | References: | | |
|
Group
Protect Physical Console Access
Group contains 1 rule |
[ref]
It is impossible to fully protect a system from an
attacker with physical access, so securing the space in which the
system is located should be considered a necessary step. However,
there are some steps which, if taken, make it more difficult for an
attacker to quickly or undetectably modify a system from its
console. |
Rule
Configure Logind to terminate idle sessions after certain time of inactivity
[ref] | To configure logind service to terminate inactive user sessions
after 600 seconds, edit the file
/etc/systemd/logind.conf . Ensure that there is a section
[Login] which contains the configuration
StopIdleSessionSec=600
. | Rationale: | Terminating an idle session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management
session enabled on the console or console port that has been let unattended. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_logind_session_timeout | References: | cis-csc | 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8 | cjis | 5.5.6 | cobit5 | APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | cui | 3.1.11 | disa | CCI-001133 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2 | iso27001-2013 | A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5 | nerc-cip | CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3 | nist | CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a) | nist-csf | DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2 | ospp | FMT_SMF_EXT.1.1 | pcidss | Req-8.1.8 | os-srg | SRG-OS-000163-GPOS-00072 | stigid | OL08-00-020035 | anssi | R32 | stigref | SV-257259r970703_rule |
| |
|
Group
Protect Accounts by Restricting Password-Based Login
Group contains 3 groups and 5 rules |
[ref]
Conventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
Group
Set Password Expiration Parameters
Group contains 2 rules |
[ref]
The file /etc/login.defs controls several
password-related settings. Programs such as passwd ,
su , and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS ( -m ) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE ( -W ) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER
|
Rule
Set Password Minimum Length in login.defs
[ref] | To specify password length requirements for new accounts, edit the file
/etc/login.defs and add or correct the following line:
PASS_MIN_LEN 15
The DoD requirement is 15 .
The FISMA requirement is 12 .
The profile requirement is
15 .
If a program consults /etc/login.defs and also another PAM module
(such as pam_pwquality ) during a password change operation, then
the most restrictive must be satisfied. See PAM section for more
information about enforcing password quality requirements. | Rationale: | 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. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_minlen_login_defs | References: | cis-csc | 1, 12, 15, 16, 5 | cjis | 5.6.2.1 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | cui | 3.5.7 | disa | CCI-004066 | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nist | IA-5(f), IA-5(1)(a), CM-6(a) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | os-srg | SRG-OS-000078-GPOS-00046 | stigid | OL08-00-020231 | anssi | R31 | stigref | SV-248700r1015059_rule |
| |
|
Rule
Set Root Account Password Maximum Age
[ref] | Configure the root account to enforce a 365-day maximum password lifetime restriction by running the following command:
$ sudo chage -M 365 root
| Rationale: | Any password, no matter how complex, can eventually be cracked. Therefore,
passwords need to be changed periodically. If the operating system does
not limit the lifetime of passwords and force users to change their
passwords, there is the risk that the operating system passwords could be
compromised. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_set_max_life_root | References: | | |
|
Group
Verify Proper Storage and Existence of Password
Hashes
Group contains 2 rules |
[ref]
By default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow . This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd , or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. |
Rule
Set number of Password Hashing Rounds - password-auth
[ref] | Configure the number or rounds for the password hashing algorithm. This can be
accomplished by using the rounds option for the pam_unix PAM module.
In file /etc/pam.d/password-auth append rounds=11
to the pam_unix.so entry, as shown below:
password sufficient pam_unix.so ...existing_options... rounds=11
The system's default number of rounds is 5000. Warning:
Setting a high number of hashing rounds makes it more difficult to brute force the password,
but requires more CPU resources to authenticate users. | Rationale: | Using a higher number of rounds makes password cracking attacks more difficult. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_unix_rounds_password_auth | References: | | |
|
Rule
Set number of Password Hashing Rounds - system-auth
[ref] | Configure the number or rounds for the password hashing algorithm. This can be
accomplished by using the rounds option for the pam_unix PAM module.
In file /etc/pam.d/system-auth append rounds=11
to the pam_unix.so entry, as shown below:
password sufficient pam_unix.so ...existing_options... rounds=11
The system's default number of rounds is 5000. Warning:
Setting a high number of hashing rounds makes it more difficult to brute force the password,
but requires more CPU resources to authenticate users. | Rationale: | Using a higher number of rounds makes password cracking attacks more difficult. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_unix_rounds_system_auth | References: | | |
|
Group
Restrict Root Logins
Group contains 1 rule |
[ref]
Direct root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/* .
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. |
Rule
Direct root Logins Not Allowed
[ref] | 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 the system as root via Telnet, which sends the password in
plain text over the network. By default, Oracle Linux 8's
/etc/securetty file only allows the root user to login at the console
physically attached to the system. To prevent root from logging in, remove the
contents of this file. To prevent direct root logins, remove the contents of this
file by typing the following command:
$ sudo echo > /etc/securetty
Warning:
This rule only checks the /etc/securetty file existence and its content.
If you need to restrict user access using the /etc/securetty file, make sure
the pam_securetty.so PAM module is properly enabled in relevant PAM files. | Rationale: | 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. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_no_direct_root_logins | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10 | cui | 3.1.1, 3.1.6 | hipaa | 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii) | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1 | iso27001-2013 | A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3 | nerc-cip | CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3 | nist | IA-2, CM-6(a) | nist-csf | PR.AC-1, PR.AC-6, PR.AC-7 | anssi | R33 | pcidss4 | 8.6.1, 8.6 |
| |
|
Group
Secure Session Configuration Files for Login Accounts
Group contains 9 rules |
[ref]
When a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
Rule
Configure Polyinstantiation of /tmp Directories
[ref] | To configure polyinstantiated /tmp directories, first create the parent directories
which will hold the polyinstantiation child directories. Use the following command:
$ sudo mkdir --mode 000 /tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf :
/tmp /tmp/tmp-inst/ level root,adm
| Rationale: | Polyinstantiation of temporary directories is a proactive security measure
which reduces chances of attacks that are made possible by /tmp
directories being world-writable. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_polyinstantiated_tmp | References: | | |
|
Rule
Configure Polyinstantiation of /var/tmp Directories
[ref] | To configure polyinstantiated /tmp directories, first create the parent directories
which will hold the polyinstantiation child directories. Use the following command:
$ sudo mkdir --mode 000 /var/tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf :
/var/tmp /var/tmp/tmp-inst/ level root,adm
| Rationale: | Polyinstantiation of temporary directories is a proactive security measure
which reduces chances of attacks that are made possible by /var/tmp
directories being world-writable. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_polyinstantiated_var_tmp | References: | | |
|
Rule
Set Interactive Session Timeout
[ref] | Setting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity.
The value of TMOUT should be exported and read only.
The TMOUT
setting in a file loaded by /etc/profile , e.g.
/etc/profile.d/tmout.sh should read as follows:
typeset -xr TMOUT=600
or
declare -xr TMOUT=600
Using the typeset keyword is preferred for wider compatibility with ksh and other shells. | Rationale: | Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_tmout | References: | cis-csc | 1, 12, 15, 16 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | cui | 3.1.11 | disa | CCI-000057, CCI-001133 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nerc-cip | CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3 | nist | AC-12, SC-10, AC-2(5), CM-6(a) | nist-csf | PR.AC-7 | os-srg | SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010 | anssi | R32 | pcidss4 | 8.6.1, 8.6 |
| |
|
Rule
User Initialization Files Must Be Group-Owned By The Primary Group
[ref] | Change the group owner of interactive users files to the group found
in /etc/passwd for the user. To change the group owner of a local
interactive user home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER/.INIT_FILE
This rule ensures every initialization file related to an interactive user
is group-owned by an interactive user. Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the group-ownership
of their respective initialization files. | Rationale: | Local initialization files for interactive users are used to configure the
user's shell environment upon logon. Malicious modification of these files could
compromise accounts upon logon. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_user_dot_group_ownership | References: | | |
|
Rule
User Initialization Files Must Be Owned By the Primary User
[ref] | Set the owner of the user initialization files for interactive users to
the primary owner with the following command:
$ sudo chown USER /home/USER/.*
This rule ensures every initialization file related to an interactive user
is owned by an interactive user. Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the ownership of
their respective initialization files. | Rationale: | Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_user_dot_user_ownership | References: | | |
|
Rule
All User Files and Directories In The Home Directory Must Be Group-Owned By The Primary Group
[ref] | Change the group of a local interactive users files and directories to a
group that the interactive user is a member of. To change the group owner of a
local interactive users files and directories, use the following command:
$ sudo chgrp USER_GROUP /home/USER/FILE_DIR
This rule ensures every file or directory under the home directory related
to an interactive user is group-owned by an interactive user. Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the group-ownership
of folders or files in their respective home directories. | Rationale: | If a local interactive users files are group-owned by a group of which the
user is not a member, unintended users may be able to access them. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_users_home_files_groupownership | References: | | |
|
Rule
All User Files and Directories In The Home Directory Must Have a Valid Owner
[ref] | Either remove all files and directories from the system that
do not have a valid user, or assign a valid user to all unowned
files and directories. To assign a valid owner to a local
interactive user's files and directories, use the following command:
$ sudo chown -R USER /home/USER
This rule ensures every file or directory under the home directory related
to an interactive user is owned by an interactive user. Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the ownership of
folders or files in their respective home directories. | Rationale: | If local interactive users do not own the files in their directories,
unauthorized users may be able to access them. Additionally, if files are not
owned by the user, this could be an indication of system compromise. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_users_home_files_ownership | References: | | |
|
Rule
All User Files and Directories In The Home Directory Must Have Mode 0750 Or Less Permissive
[ref] | Set the mode on files and directories in the local interactive user home
directory with the following command:
$ sudo chmod 0750 /home/USER/FILE_DIR
Files that begin with a "." are excluded from this requirement. | Rationale: | If a local interactive user files have excessive permissions, unintended users
may be able to access or modify them. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_users_home_files_permissions | References: | | |
|
Rule
Ensure All User Initialization Files Have Mode 0740 Or Less Permissive
[ref] | Set the mode of the user initialization files to 0740 with the
following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE
| Rationale: | Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_permission_user_init_files | References: | | |
|
Rule
Enable authselect
[ref] | Configure user authentication setup to use the authselect tool.
If authselect profile is selected, the rule will enable the minimal profile. Warning:
If the sudo authselect select command returns an error informing that the chosen
profile cannot be selected, it is probably because PAM files have already been modified by
the administrator. If this is the case, in order to not overwrite the desired changes made
by the administrator, the current PAM settings should be investigated before forcing the
selection of the chosen authselect profile. | Rationale: | Authselect is a successor to authconfig.
It is a tool to select system authentication and identity sources from a list of supported
profiles instead of letting the administrator manually build the PAM stack.
That way, it avoids potential breakage of configuration, as it ships several tested profiles
that are well tested and supported to solve different use-cases. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_enable_authselect | References: | disa | CCI-000213 | hipaa | 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii) | nist | AC-3 | ospp | FIA_UAU.1, FIA_AFL.1 | os-srg | SRG-OS-000480-GPOS-00227 | anssi | R31 | pcidss4 | 8.3.4, 8.3 |
| |
|
Group
GRUB2 bootloader configuration
Group contains 2 groups and 9 rules |
[ref]
During the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default Oracle Linux 8 boot loader for x86 systems is called GRUB2.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly. |
Group
Non-UEFI GRUB2 bootloader configuration
Group contains 1 rule |
[ref]
Non-UEFI GRUB2 bootloader configuration |
Rule
Set Boot Loader Password in grub2
[ref] | The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. | Rationale: | 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. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_password | References: | cis-csc | 1, 11, 12, 14, 15, 16, 18, 3, 5 | cobit5 | DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10 | cui | 3.4.5 | disa | CCI-000213 | hipaa | 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii) | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7 | iso27001-2013 | A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5 | nist | CM-6(a) | nist-csf | PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3 | os-srg | SRG-OS-000080-GPOS-00048 | stigid | OL08-00-010150 | anssi | R5 | stigref | SV-248540r958472_rule |
| |
|
Group
UEFI GRUB2 bootloader configuration
Group contains 1 rule |
[ref]
UEFI GRUB2 bootloader configuration Warning:
UEFI generally uses vfat file systems, which does not support Unix-style permissions
managed by chmod command. In this case, in order to change file permissions for files
within /boot/efi it is necessary to update the mount options in /etc/fstab file and
reboot the system. |
Rule
Set the UEFI Boot Loader Password
[ref] | The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. | Rationale: | 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. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_uefi_password | References: | cis-csc | 11, 12, 14, 15, 16, 18, 3, 5 | cobit5 | DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06 | cui | 3.4.5 | disa | CCI-000213 | hipaa | 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii) | isa-62443-2009 | 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7 | iso27001-2013 | A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5 | nist | CM-6(a) | nist-csf | PR.AC-4, PR.AC-6, PR.PT-3 | ospp | FIA_UAU.1 | os-srg | SRG-OS-000080-GPOS-00048 | stigid | OL08-00-010140 | anssi | R5 | stigref | SV-248537r958472_rule |
| |
|
Rule
Configure L1 Terminal Fault mitigations
[ref] | L1 Terminal Fault (L1TF) is a hardware vulnerability which allows unprivileged
speculative access to data which is available in the Level 1 Data Cache when
the page table entry isn't present.
Select the appropriate mitigation by adding the argument
l1tf=full,force
to the default
GRUB 2 command line for the Linux operating system.
To ensure that l1tf=full,force
is added as a kernel command line
argument to newly installed kernels, add l1tf=full,force
to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... l1tf=full,force ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="l1tf=full,force"
Since Linux Kernel 4.19 you can check the L1TF vulnerability state with the
following command:
cat /sys/devices/system/cpu/vulnerabilities/l1tf
Warning:
Enabling L1TF mitigations may impact performance of the system. | Rationale: | The L1TF vulnerability allows an attacker to bypass memory access security controls imposed
by the system or hypervisor. The L1TF vulnerability allows read access to any physical memory
location that is cached in the L1 Data Cache. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_l1tf_argument | References: | | |
|
Rule
Force kernel panic on uncorrected MCEs
[ref] | A Machine Check Exception is an error generated by the CPU itdetects an error
in itself, memory or I/O devices.
These errors may be corrected and generate a check log entry, if an error
cannot be corrected the kernel may panic or SIGBUS.
To force the kernel to panic on any uncorrected error reported by Machine Check
set the MCE tolerance to zero by adding mce=0
to the default GRUB 2 command line for the Linux operating system.
To ensure that mce=0 is added as a kernel command line
argument to newly installed kernels, add mce=0 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... mce=0 ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="mce=0"
| Rationale: | Allowing uncorrected errors to result on a SIGBUS may allow an attacker to continue
trying to exploit a vulnerability such as Rowhammer. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_mce_argument | References: | | |
|
Rule
Enable Kernel Page-Table Isolation (KPTI)
[ref] | To enable Kernel page-table isolation,
add the argument pti=on to the default
GRUB 2 command line for the Linux operating system.
To ensure that pti=on is added as a kernel command line
argument to newly installed kernels, add pti=on to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... pti=on ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="pti=on"
| Rationale: | Kernel page-table isolation is a kernel feature that mitigates
the Meltdown security vulnerability and hardens the kernel
against attempts to bypass kernel address space layout
randomization (KASLR). | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_pti_argument | References: | | |
|
Rule
Configure the confidence in TPM for entropy
[ref] | The TPM security chip that is available in most modern systems has a hardware RNG.
It is also used to feed the entropy pool, but generally not credited entropy.
Use rng_core.default_quality in the kernel command line to set the trust
level on the hardware generators. The trust level defines the amount of entropy to credit.
A value of 0 tells the system not to trust the hardware random number generators
available, and doesn't credit any entropy to the pool.
A value of 1000 assigns full confidence in the generators, and credits all the
entropy it provides to the pool.
Note that the value of rng_core.default_quality is global, affecting the trust
on all hardware random number generators.
Select the appropriate confidence by adding the argument
rng_core.default_quality=500
to the default
GRUB 2 command line for the Linux operating system.
To ensure that rng_core.default_quality=500
is added as a kernel command line
argument to newly installed kernels, add rng_core.default_quality=500
to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... rng_core.default_quality=500 ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="rng_core.default_quality=500"
| Rationale: | A system may struggle to initialize its entropy pool and end up starving. Crediting entropy
from the hardware number generators available in the system helps fill up the entropy pool. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_rng_core_default_quality_argument | References: | | |
|
Rule
Disable merging of slabs with similar size
[ref] | The kernel may merge similar slabs together to reduce overhead and increase
cache hotness of objects.
Disabling merging of slabs keeps the slabs separate and reduces the risk of
kernel heap overflows overwriting objects in merged caches.
To disable merging of slabs in the Kernel add the argument slab_nomerge=yes
to the default GRUB 2 command line for the Linux operating system.
To ensure that slab_nomerge=yes is added as a kernel command line
argument to newly installed kernels, add slab_nomerge=yes to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... slab_nomerge=yes ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="slab_nomerge=yes"
Warning:
Disabling merge of slabs will slightly increase kernel memory utilization. | Rationale: | Disabling the merge of slabs of similar sizes prevents the kernel from
merging a seemingly useless but vulnerable slab with a useful and valuable slab.
This increase the risk that a heap overflow could overwrite objects from merged caches,
with unmerged caches the heap overflow would only affect the objects in the same cache.
Overall, this reduces the kernel attack surface area by isolating slabs from each other. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_slab_nomerge_argument | References: | | |
|
Rule
Configure Speculative Store Bypass Mitigation
[ref] | Certain CPUs are vulnerable to an exploit against a common wide industry wide performance
optimization known as Speculative Store Bypass (SSB).
In such cases, recent stores to the same memory location cannot always be observed by later
loads during speculative execution. However, such stores are unlikely and thus they can be
detected prior to instruction retirement at the end of a particular speculation execution
window.
Since Linux Kernel 4.17 you can check the SSB mitigation state with the following command:
cat /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
Select the appropriate SSB state by adding the argument
spec_store_bypass_disable=seccomp
to the default
GRUB 2 command line for the Linux operating system.
To ensure that spec_store_bypass_disable=seccomp
is added as a kernel command line
argument to newly installed kernels, add spec_store_bypass_disable=seccomp
to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... spec_store_bypass_disable=seccomp ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="spec_store_bypass_disable=seccomp"
Warning:
Disabling Speculative Store Bypass may impact performance of the system. | Rationale: | In vulnerable processsors, the speculatively forwarded store can be used in a cache side channel
attack. An example of this is reading memory to which the attacker does not directly have access,
for example inside the sandboxed code. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_spec_store_bypass_disable_argument | References: | | |
|
Rule
Enforce Spectre v2 mitigation
[ref] | Spectre V2 is an indirect branch poisoning attack that can lead to data leakage.
An exploit for Spectre V2 tricks the indirect branch predictor into executing
code from a future indirect branch chosen by the attacker, even if the privilege
level is different.
Since Linux Kernel 4.15 you can check the Spectre V2 mitigation state with the following command:
cat /sys/devices/system/cpu/vulnerabilities/spectre_v2
Enforce the Spectre V2 mitigation by adding the argument
spectre_v2=on to the default
GRUB 2 command line for the Linux operating system.
To ensure that spectre_v2=on is added as a kernel command line
argument to newly installed kernels, add spectre_v2=on to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... spectre_v2=on ..."
Run the following command to update command line for already installed kernels: # grubby --update-kernel=ALL --args="spectre_v2=on"
| Rationale: | The Spectre V2 vulnerability allows an attacker to read memory that he should not have
access to. | Severity: | high | Rule ID: | xccdf_org.ssgproject.content_rule_grub2_spectre_v2_argument | References: | | |
|
Group
Network Configuration and Firewalls
Group contains 8 groups and 53 rules |
[ref]
Most systems must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
Group
IPSec Support
Group contains 9 rules |
[ref]
Support for Internet Protocol Security (IPsec)
is provided with Libreswan. |
Rule
Verify Group Who Owns /etc/ipsec.d Directory
[ref] | To properly set the group owner of /etc/ipsec.d , run the command: $ sudo chgrp root /etc/ipsec.d
| Rationale: | The ownership of the /etc/ipsec.d directory by the root group is important
because this directory hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_groupowner_etc_ipsecd | References: | | |
|
Rule
Verify User Who Owns /etc/ipsec.d Directory
[ref] | To properly set the owner of /etc/ipsec.d , run the command: $ sudo chown root /etc/ipsec.d
| Rationale: | The ownership of the /etc/ipsec.d directory by the root user is important
because this directory hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_owner_etc_ipsecd | References: | | |
|
Rule
Verify Permissions On /etc/ipsec.d Directory
[ref] | To properly set the permissions of /etc/ipsec.d , run the command: $ sudo chmod 0700 /etc/ipsec.d
| Rationale: | Setting correct permissions on the /etc/ipsec.d directory is important
because this directory hosts Libreswan configuration. Protection of this
directory is critical for system security. Restricting the permissions
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_permissions_etc_ipsecd | References: | | |
|
Rule
Verify Group Who Owns /etc/ipsec.conf File
[ref] | To properly set the group owner of /etc/ipsec.conf , run the command: $ sudo chgrp root /etc/ipsec.conf
| Rationale: | The ownership of the /etc/ipsec.conf file by the root group is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_ipsec_conf | References: | | |
|
Rule
Verify Group Who Owns /etc/ipsec.secrets File
[ref] | To properly set the group owner of /etc/ipsec.secrets , run the command: $ sudo chgrp root /etc/ipsec.secrets
| Rationale: | The ownership of the /etc/ipsec.secrets file by the root group is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_ipsec_secrets | References: | | |
|
Rule
Verify User Who Owns /etc/ipsec.conf File
[ref] | To properly set the owner of /etc/ipsec.conf , run the command: $ sudo chown root /etc/ipsec.conf
| Rationale: | The ownership of the /etc/ipsec.conf file by the root user is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_ipsec_conf | References: | | |
|
Rule
Verify User Who Owns /etc/ipsec.secrets File
[ref] | To properly set the owner of /etc/ipsec.secrets , run the command: $ sudo chown root /etc/ipsec.secrets
| Rationale: | The ownership of the /etc/ipsec.secrets file by the root user is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_ipsec_secrets | References: | | |
|
Rule
Verify Permissions On /etc/ipsec.conf File
[ref] | To properly set the permissions of /etc/ipsec.conf , run the command: $ sudo chmod 0644 /etc/ipsec.conf
| Rationale: | Setting correct permissions on the /etc/ipsec.conf file is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Restricting the permissions
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_ipsec_conf | References: | | |
|
Rule
Verify Permissions On /etc/ipsec.secrets File
[ref] | To properly set the permissions of /etc/ipsec.secrets , run the command: $ sudo chmod 0644 /etc/ipsec.secrets
| Rationale: | Setting correct permissions on the /etc/ipsec.secrets file is important
because this file hosts Libreswan configuration. Protection of this
file is critical for system security. Restricting the permissions
ensures exclusive control of the Libreswan configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_ipsec_secrets | References: | | |
|
Group
iptables and ip6tables
Group contains 3 rules |
[ref]
A host-based firewall called netfilter is included as
part of the Linux kernel distributed with the system. It is
activated by default. This firewall is controlled by the program
iptables , and the entire capability is frequently referred to by
this name. An analogous program called ip6tables handles filtering
for IPv6.
Unlike TCP Wrappers, which depends on the network server
program to support and respect the rules written, netfilter
filtering occurs at the kernel level, before a program can even
process the data from the network packet. As such, any program on
the system is affected by the rules written.
This section provides basic information about strengthening
the iptables and ip6tables configurations included with the system.
For more complete information that may allow the construction of a
sophisticated ruleset tailored to your environment, please consult
the references at the end of this section. |
Rule
Verify Group Who Owns /etc/iptables Directory
[ref] | To properly set the group owner of /etc/iptables , run the command: $ sudo chgrp root /etc/iptables
| Rationale: | The ownership of the /etc/iptables directory by the root group is important
because this directory hosts iptables configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the iptables configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_groupowner_etc_iptables | References: | | |
|
Rule
Verify User Who Owns /etc/iptables Directory
[ref] | To properly set the owner of /etc/iptables , run the command: $ sudo chown root /etc/iptables
| Rationale: | The ownership of the /etc/iptables directory by the root user is important
because this directory hosts iptables configuration. Protection of this
file is critical for system security. Assigning the ownership to root
ensures exclusive control of the iptables configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_owner_etc_iptables | References: | | |
|
Rule
Verify Permissions On /etc/iptables Directory
[ref] | To properly set the permissions of /etc/iptables , run the command: $ sudo chmod 0700 /etc/iptables
| Rationale: | Setting correct permissions on the /etc/iptables directory is important
because this directory hosts iptables configuration. Protection of this
directory is critical for system security. Restricting the permissions
ensures exclusive control of the iptables configuration. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_directory_permissions_etc_iptables | References: | |
|