NixOS must notify the system administrator (SA) and information system security officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 90 percent utilization.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-268102 | ANIX-00-000410 | SV-268102r1039601_rule | CCI-000139 | medium |
| Description | ||||
| If security personnel are not notified immediately when storage volume reaches 90 percent utilization, they are unable to plan for audit record storage capacity expansion. | ||||
| STIG | Date | |||
| Anduril NixOS Security Technical Implementation Guide | 2024-10-25 | |||
Details
Check Text (C-268102r1039601_chk)
Verify NixOS notifies the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 90 percent of the repository maximum audit record storage capacity with the following command:
$ sudo grep -w admin_space_left_action /etc/audit/auditd.conf
admin_space_left_action = syslog
If the "admin_space_left_action" parameter is missing, commented out, or set to blanks, this is a finding.
If the "admin_space_left_action" is set to "syslog", the system logs the event, but does not generate a notification, this is a finding.
If the "admin_space_left_action" is set to "exec", the system executes a designated script. If this script does not inform the SA of the event, this is a finding.
If the "admin_space_left_action" is set to "email" check the value of the "action_mail_acct" parameter with the following command:
$ sudo grep action_mail_acct /etc/audit/auditd.conf
action_mail_acct root@localhost
The "action_mail_acct" parameter, if missing, defaults to "root". If the "action_mail_acct" parameter is not set to the email address of the SA and/or ISSO, this is a finding.
Note: If the email address of the SA is on a remote system, a mail package must be available.
Fix Text (F-71929r1039570_fix)
Configure NixOS to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 90 percent of the repository maximum audit record storage capacity.
If the space_left_action parameter is set to "syslog", make sure the event being logged generates a notification to the SA and ISSO.
If the space_left_action parameter is set to "exec", make sure the command being execute notifies the SA and ISSO.
If the space_left_action parameter is set to "email" set the action_mail_acct parameter to an email address for the SA and ISSO.
Add or update the 'environment.etc."audit/auditd.conf".text' configuration in /etc/nixos/configuration.nix to include the following:
admin_space_left_action = syslog
For example, an updated configuration of 'environment.etc."audit/auditd.conf".text' would look like the following in /etc/nixos/configuration.nix ('...' denoting that the 'environment.etc."audit/auditd.conf".text' configuration may have other options configured):
environment.etc."audit/auditd.conf".text = [
''
...
admin_space_left_action = syslog
...
''
];
Rebuild the NixOS configuration with the following command:
$ sudo nixos-rebuild switch