People spend a lot of time preparing for effective dictionary attack. Common User Passwords Profiler (CUPP) is made to simplify this attack method that is often used as last resort in penetration testing and forensic crime investigations. A weak password might be very short or only use alphanumeric characters, making decryption simple. A weak password can also be one that is easily guessed by someone profiling the user, such as a birthday, nickname, address, name of a pet or relative, or a common word such as God, love, money or password.
Going through different combinations and algorithms, CUPP can predict specific target passwords by exploiting human vulnerabilities. In password creation, as in many aspects of life, everybody tends to the original solution, but thanks to human nature, we all tend to originality in the same way, leading to almost absolute predictability.