# John the Ripper

While you can use popular wordlists like RockYou, John the Ripper also has its own set of wordlists with thousands of common passwords. This makes John very effective when cracking systems with weak passwords.

No mode needs to be entered. John recognises the hash type, generates hashes on the fly for all the passwords in the dictionary, and stops when a generated hash matches the current hash.

If you are using Kali Linux, John is pre-installed.

$john --single --format=raw-sha1 crackthishash.txt  crackthishash.txt contains username and hash value of the password (separated by a colon). Dictionary attack: $ john --wordlist=/usr/share/wordlists/rockyou.txt --format=raw-sha1 crackthishash.txt