Title

The RHEL 8 audit system must take appropriate action when the audit storage volume is full. (Cat II impact)

Discussion

It is critical that when RHEL 8 is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When availability is an overriding concern, other approved actions in response to an audit failure are as follows: 1) If the failure was caused by the lack of audit record storage capacity, RHEL 8 must continue generating audit records if possible (automatically restarting the audit service if necessary) and overwriting the oldest audit records in a first-in-first-out manner. 2) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, RHEL 8 must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

Check Content

Verify RHEL 8 takes the appropriate action when the audit storage volume is full. Check that RHEL 8 takes the appropriate action when the audit storage volume is full with the following command: $ sudo grep disk_full_action /etc/audit/auditd.conf disk_full_action = HALT If the value of the "disk_full_action" option is not "SYSLOG", "SINGLE", or "HALT", or the line is commented out, ask the system administrator to indicate how the system takes appropriate action when an audit storage volume is full. If there is no evidence of appropriate action, this is a finding.

Fix Text

Configure RHEL 8 to shut down by default upon audit failure (unless availability is an overriding concern). Add or update the following line (depending on configuration "disk_full_action" can be set to "SYSLOG" or "SINGLE" depending on configuration) in "/etc/audit/auditd.conf" file: disk_full_action = HALT If availability has been determined to be more important, and this decision is documented with the ISSO, configure the operating system to notify system administration staff and ISSO staff in the event of an audit processing failure by setting the "disk_full_action" to "SYSLOG".

Additional Identifiers

Rule ID: SV-230392r627750_rule

Vulnerability ID: V-230392

Group Title: SRG-OS-000047-GPOS-00023

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.