Description:

John the Ripper is a fast password cracker, currently available for
many flavors of Unix (11 are officially supported, not counting
different architectures), DOS, Win32, BeOS, and OpenVMS (the latter
requires a contributed patch). Its primary purpose is to detect weak
Unix passwords. Besides several crypt(3) password hash types most
commonly found on various Unix flavors, supported out of the box are
Kerberos/AFS and Windows NT/2000/XP LM hashes, plus several more with
contributed patches.