Purple Knight - Purple Knight is a free Active Directory security assessment tool built and managed by an elite group of Microsoft identity experts.

ManageEngine ADAudit - ManageEngine ADAudit is a real-time windows active directory auditing tool.

PingCastle - Because the Active Directory security lies in the process and not in expensive tools, our solution is simple: download PingCastle and apply its methodology.

NetWrix Auditor - Configuration Auditing of IT Infrastructure