Software designed to allow users to decrypt or recover lost or unknown passwords. In the hands of security administrators these may be legitimate tools, however password crackers can be a security and privacy threat when used maliciously by unauthorized users.
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