John the Ripper is a free password cracking software tool. Originally developed for the Unix operating system, it can run on fifteen different platforms.
Mutations
Config file
/etc/john/john.conf
Modify the config file
# Add two numbers to the end of each password
$[0-9]$[0-9]
john --wordlist=megacorp-cewl.txt --rules --stdout > mutated.txt
Hash attacks
Brute force (all)
john <file-with-hashes>
Using wordlist
john --wordlist=/usr/share/wordlists/rockyou.txt <file-with-hashes>
Single Crack Mode
John will create it's own dictionary list based on additional information provided (e.g. username).
Fileformat (Gecos)
username:password
john --single <file-with-hashes>
Rules
Applying rules
Word mangling rules are used to modify or "mangle" words producing other likely passwords
john --rules --wordlist=/usr/share/wordlists/rockyou.txt <file-with-hashes>
