A piece of software that looks at some one's password and tries to break it by guessing using brute force and/or highly sophisticated artificial intelligence. Passwords like "snoopy" are easy to crack, but a password like "accelR8" is much harder.
Password Cracking refers to software that breaks the encryption or passwords stored on the server. It works best on simple passwords and allows attackers to gain access through a valid user's account. This is possible because users select weak passwords that are easily "cracked".
Password cracking is the process of recovering secret passwords from data that has been stored in or transmitted by a computer system. A common approach is to repeatedly try guesses for the password. The purpose of password cracking might be to help a user recover a forgotten password (though installing an entirely new password is less of a security risk, but involves system administration privileges), to gain unauthorized access to a system, or as a preventive measure by system administrators to check for easily crackable passwords.