Record Successful Permission Changes to Files - fchmodat
An XCCDF Rule
Description
At a minimum, the audit system should collect file permission changes
for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmodat -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-perm-changeIf the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S fchmodat -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-perm-changeIf the
auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-perm-changeIf the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S fchmodat -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-perm-change
warning alert: Warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
Rationale
File permission changes could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
- ID
- xccdf_org.ssgproject.content_rule_audit_rules_successful_file_modification_fchmodat
- Severity
- Medium
- Updated