cis-ubuntu1804-v220-5-1-2-4

DevOps & Security

Ensure rsyslog default file permissions are configured

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_18.04_LTS_Benchmark_v2.2.0/cis-ubuntu1804-v220-5-1-2-4/SKILL.md

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5.1.2.4 Ensure rsyslog default file permissions are configured (Automated)

Profile

Level: 1 - Server
Level: 1 - Workstation
Assessment Status: Automated

Description

RSyslog will create logfiles that do not already exist on the system. This setting controls what permissions will be applied to these newly created files.

Rationale

It is important to ensure that log files have the correct permissions to ensure that sensitive data is archived and protected.

Impact

The systems global umask could override, but only making the file permissions stricter, what is configured in RSyslog with the FileCreateMode directive. RSyslog also has it's own $umask directive that can alter the intended file creation mode. In addition, consideration should be given to how FileCreateMode is used.

Thus it is critical to ensure that the intended file creation mode is not overridden with less restrictive settings in /etc/rsyslog.conf, /etc/rsyslog.d/*conf files and that FileCreateMode is set before any file is created.

Audit Procedure

Command Line

Run the following command:

grep ^\$FileCreateMode /etc/rsyslog.conf /etc/rsyslog.d/*.conf

Verify the output matches:

$FileCreateMode 0640

Should a site policy dictate less restrictive permissions, ensure to follow said policy. NOTE: More restrictive permissions such as 0600 is implicitly sufficient.

Expected Result

The output should show $FileCreateMode 0640 or more restrictive.

Remediation

Command Line

Edit either /etc/rsyslog.conf or a dedicated .conf file in /etc/rsyslog.d/ and set $FileCreateMode to 0640 or more restrictive:

$FileCreateMode 0640

Restart the service:

systemctl restart rsyslog

Default Value

$FileCreateMode 0640

References

See the rsyslog.conf(5) man page for more information.
NIST SP 800-53 Rev. 5: AC-3, AC-6, MP-2

CIS Controls

Controls Version	Control
v8	3.3 Configure Data Access Control Lists - Configure data access control lists based on a user's need to know. Apply data access control lists, also known as access permissions, to local and remote file systems, databases, and applications.
v8	8.2 Collect Audit Logs - Collect audit logs. Ensure that logging, per the enterprise's audit log management process, has been enabled across enterprise assets.
v7	5.1 Establish Secure Configurations - Maintain documented, standard security configuration standards for all authorized operating systems and software.
v7	6.2 Activate audit logging - Ensure that local logging has been enabled on all systems and networking devices.
v7	6.3 Enable Detailed Logging - Enable system logging to include detailed information such as an event source, date, user, timestamp, source addresses, destination addresses, and other useful elements.