Nbtool - Skull Security: "* NetBIOS lookups
* NetBIOS registrations
* NetBIOS poisoning
The poisoning is the most interesting part. It will respond to any NetBIOS lookup with a given address, effectively poisoning everything that wasn't found, and even some stuff that was (if it wins the race). Additionally, it will send a NetBIOS conflict to anything new that tries to register, effectively stealing their names."
