L0phtcrack : Windows password auditing and recovery application
L0phtCrack, also known as LC5, attempts to crack Windows passwords from hashes which it can obtain (given proper access) from stand-alone Windows NT/2000 workstations, networked servers, primary domain controllers, or Active Directory. In some cases it can sniff the hashes off the wire. It also has numerous methods of generating password guesses (dictionary, brute force, etc). LC5 was discontinued by Symantec in 2006, but you can still find the LC5 installer floating around. The free trial only lasts 15 days, and Symantec won't sell you a key, so you'll either have to cease using it or find a key generator.
