john, better known as John the Ripper, is a tool to find weak passwords of users in a server. John can use a dictionary or some search pattern as well as a password file to check for passwords. John supports different cracking modes and understands many ciphertext formats, like several DES variants, MD5 and blowfish. It can also be used to extract AFS and Windows NT passwords.
john [OPTIONS] [PASSWORD-FILES]
--single "single crack" mode --wordlist=FILE --stdin wordlist mode, read words from FILE or stdin --rules enable word mangling rules for wordlist mode --incremental[=MODE] "incremental" mode [using section MODE] --external=MODE external mode or word filter --stdout[=LENGTH] just output candidate passwords [cut at LENGTH] --restore[=NAME] restore an interrupted session [called NAME] --session=NAME give a new session the NAME --status[=NAME] print status of a session [called NAME] --make-charset=FILE make a charset, FILE will be overwritten --show show cracked passwords --test[=TIME] run tests and benchmarks for TIME seconds each --users=[-]LOGIN|UID[,..] [do not] load this (these) user(s) only --groups=[-]GID[,..] load users [not] of this (these) group(s) only --shells=[-]SHELL[,..] load users with[out] this (these) shell(s) only --salts=[-]N load salts with[out] at least N passwords only --save-memory=LEVEL enable memory saving, at LEVEL 1..3 --node=MIN[-MAX]/TOTAL this node's number range out of TOTAL count --fork=N fork N processes --format=NAME force hash type NAME: descrypt/bsdicrypt/md5crypt/ bcrypt/LM/AFS/tripcode/dummy/crypt
UnShoadow Linux Password details :
The unshadow command will basically combine the data of /etc/passwd and /etc/shadow to create 1 file with username and password details. Usage is quite simple.
cyborg@cyborg:~$ sudo unshadow /etc/passwd /etc/shadow > johntocrack [sudo] password for cyborg:
Crack with John
Now this new file shall be cracked by john. For the wordlist we shall be using the password list that comes with john on kali linux. It is located at the following path
cyborg@cyborg:~$ sudo john --wordlist=dict.txt johntocrack Loaded 1 password hash (crypt, generic crypt(3) [?/64]) Press 'q' or Ctrl-C to abort, almost any other key for status toor (cyborg) 1g 0:00:00:00 100% 5.555g/s 16.66p/s 16.66c/s 16.66C/s password123..toor Use the "--show" option to display all of the cracked passwords reliably Session completed