PingCastle

Ping Castle is a tool designed to assess quickly the Active Directory security level with a methodology based on risk assessment and a maturity framework. It's a simple zipped download that you can just run as a normal domain user, no install required.

You can run it on an ad-hoc basis to generate a detailed HTML report, but that's just the tip of the iceberg.

Download - PingCastlePingCastle