RHEL 9 must take action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-258156	SRG-OS-000343-GPOS-00134	RHEL-09-653035	SV-258156r971542_rule	2025-02-27	2

Description
If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion.

ℹ️ Check
Verify RHEL 9 takes action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w space_left /etc/audit/auditd.conf space_left = 25% If the value of the "space_left" keyword is not set to 25 percent of the storage volume allocated to audit logs, or if the line is commented out, ask the system administrator (SA) to indicate how the system is providing real-time alerts to the SA and information system security officer (ISSO). If the "space_left" value is not configured to the correct value, this is a finding.

ℹ️ Check

Verify RHEL 9 takes action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w space_left /etc/audit/auditd.conf space_left = 25% If the value of the "space_left" keyword is not set to 25 percent of the storage volume allocated to audit logs, or if the line is commented out, ask the system administrator (SA) to indicate how the system is providing real-time alerts to the SA and information system security officer (ISSO). If the "space_left" value is not configured to the correct value, this is a finding.

✔️ Fix
Configure RHEL 9 to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. space_left = 25%