CredNinja is a tool to quickly test credential validity of dumped credentials (or hashes) across an entire network or domain very efficiently.
At the core of it, you provide it with a list of credentials you have dumped (or hashes, it can pass-the-hash) and a list of systems on the domain (the author suggests scanning for port 445 first, or you can use “–scan”). It will tell you if the credentials you dumped are valid on the domain, and if you have local administrator access to a host.
