Title

The audit system must be configured to audit failed attempts to access files and programs. (Cat III impact)

Discussion

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Check Content

To verify that the audit system collects unauthorized file accesses, run the following commands: # grep EACCES /etc/audit/audit.rules -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid=0 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid=0 -k access # grep EPERM /etc/audit/audit.rules -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid=0 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid=0 -k access If the system is 64-bit and does not return rules for both "b32" and "b64" architectures, this is a finding. If either command lacks output, this is a finding.

Fix Text

At a minimum, the audit system should collect unauthorized file accesses for all users and root. Add the following to "/etc/audit/audit.rules": -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid=0 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid=0 -k access If the system is 64-bit, then also add the following: -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EACCES -F auid=0 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S truncate \ -S ftruncate -F exit=-EPERM -F auid=0 -k access

Additional Identifiers

Rule ID: SV-217975r603264_rule

Vulnerability ID: V-217975

Group Title: SRG-OS-000064

Expert Comments

CCIs tied to check.

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