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Record Unsuccessful Permission Changes to Files - fchmod

An XCCDF Rule

Description

The audit system should collect unsuccessful file permission change attempts 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. If 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 fchmod -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-perm-change
-a always,exit -F arch=b32 -S fchmod -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-perm-change
If the system is 64 bit then also add the following lines: 
-a always,exit -F arch=b64 -S fchmod -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-perm-change
-a always,exit -F arch=b64 -S fchmod -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-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 audit rule checks a system call independently of other system calls. Grouping system calls related to the same event is more efficient. See the following example: 
-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat,setxattr,lsetxattr,fsetxattr -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-perm-change

Rationale

Unsuccessful attempts to change permissions of files 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_unsuccessful_file_modification_fchmod
Severity
Medium
References
Updated



Remediation - Kubernetes Patch


apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition: