DISA STIGS Viewer

OL 9 must be configured so that successful/unsuccessful uses of the umount system call generate an audit record.

Overview

Finding ID Version Rule ID IA Controls Severity
V-271594 OL09-00-000840 SV-271594r1092582_rule   Medium
Description
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
STIG Date
Oracle Linux 9 Security Technical Implementation Guide 2025-05-08

Details

Check Text (C-75644r1091492_chk)
Verify that OL 9 generates an audit record for all uses of the umount system call with the following commands:

$ sudo grep "umount" /etc/audit/audit.*

$ sudo grep umount /etc/audit/audit.rules

If the system is configured to audit this activity, it will return a line like the following:

-a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -k privileged-umount

If the command does not return a line or the line is commented out, this is a finding.
Fix Text (F-75551r1092581_fix)
Configure the audit system to generate an audit event for any successful/unsuccessful use of the umount system call by adding or updating the following rules in "/etc/audit/audit.rules" and adding the following rules to "/etc/audit/rules.d/perm_mod.rules" or updating the existing rules in files in the "/etc/audit/rules.d/" directory:

-a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S umount -F auid>=1000 -F auid!=unset -k perm_mod

The audit daemon must be restarted for the changes to take effect.

Restart auditd:
$ sudo service auditd restart