InformationThe operating system must audit all uses of the unlink syscall.
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
SolutionConfigure the operating system to generate audit records when successful/unsuccessful attempts to use the unlink syscall occur.
Add the following rules in /etc/audit/rules.d/audit.rules:
Example: vim /etc/audit/rules.d/audit.rules
Add, uncomment or update the following line depending on your system architecture:
Note: The rules are duplicated to cover both 32-bit and 64-bit architectures. Only the lines appropriate for the system architecture must be configured.
-a always,exit -F arch=b32 -S unlink -F auid>=1000 -F auid!=4294967295 -k delete
-a always,exit -F arch=b64 -S unlink -F auid>=1000 -F auid!=4294967295 -k delete
The audit daemon must be restarted for the changes to take effect.
# service auditd restart