Internal and external auditors independently verify that Controls are actually operating as intended, rather than just existing on paper. Internal audit typically reports to the Senior management / Board of Directors; external auditors are independent third parties, sometimes mandated by regulation (e.g. FINMA-recognised audit firms for regulated financial institutions).

Findings from an audit often surface previously unknown Vulnerabilitys or expired exceptions that were never revisited, which is why regular audit cycles are themselves considered good practice on top of ongoing control monitoring.