John the Ripper is a free password cracking software tool. Initially developed for the Unix operating system

Cracking passwords using John the Ripper

It's only fair to share...Digg thisShare on FacebookShare on Google+Tweet about this on TwitterShare on LinkedInFlattr the authorShare on TumblrShare on VKShare on YummlyShare on RedditShare on StumbleUpon

Cracking passwords using John the Ripper

 

Cracking passwords using John the Ripper. John The Ripper is a free password cracking tool that runs on a many platforms. It has become one of the best password cracking tools as it combines several other password crackers into a single package and has a number of handy features like automatic hash type detection. Password cracking in Kali Linux using this tool is very straight forward which we will discuss in this post. Cracking passwords using John the Ripper.

John the Ripper uses a 2 step process to crack a password. First, it will use the password and shadow file to create an output file. Later, you then actually use the dictionary attack against that file to crack it. To keep it simple, John the Ripper uses the following two files:

/etc/passwd
/etc/shadow

Cracking passwords using John the Ripper

In Linux, password hash is stored in /etc/shadow file. For the sake of this exercise, I will create a new user names john and assign a simple password ‘password’ to him.

I will also add john to sudo group, assign /bin/bash as his shell. There’s a nice article I posted last year which explains user creating in Linux in great details. It’s a good read if you are interested to know and understand the flags and this same structure can be used to almost any Linux/Unix/Solaris operating system. Also, when you create a user, you need their home directories created,

First, let’s create a user named john and assign password as his password. (very secured..yeah!)

cracking-password-in-kali-john-the-ripper-picateshackz-1

root@kali:~# useradd -m john -G sudo -s /bin/bash
root@kali:~# passwd john
Enter new UNIX password: <password>
Retype new UNIX password: <password>
passwd: password updated successfully
root@kali:~#

Unshadowing password

Now that we have created our victim, let’s start with unshadow commands. The unshadow command will combine the entries of /etc/passwd and /etc/shadow to create 1 file with username and password details. When you just type in unshadow, it shows you the usage anyway. Cracking passwords using John the Ripper.

ALSO READ  DirBuster tool is a great Information Gathering Tool

cracking-password-in-kali-john-the-ripper-picateshackz-2

root@kali:~# unshadow
Usage: unshadow PASSWORD-FILE SHADOW-FILE
root@kali:~# unshadow /etc/passwd /etc/shadow > /root/johns_passwd

I’ve redirected the output to /root/johns_passwd file because I got the ticks for organising things. Do what you feel like here.

Cracking process with John the Ripper

At this point, we just need a dictionary file and get on with cracking. John comes with its own small password file and it can be located in /usr/share/john/password.lst. I’ve shown the size of that file using the following command.

root@kali:~# ls -ltrah /usr/share/john/password.lst

You can use your own password lists  or just download a large one from the Internet (there’s lots of dictionary file in terabyte size).

cracking-password-in-kali-john-the-ripper-picateshackz-3

root@kali:~# john --wordlist=/usr/share/john/password.lst /root/johns_passwd 
Created directory: /root/.john
Warning: detected hash type "sha512crypt", but the string is also recognized as "crypt"
Use the "--format=crypt" option to force loading these as that type instead
Using default input encoding: UTF-8
Loaded 2 password hashes with 2 different salts (sha512crypt, crypt(3) $6$ [SHA512 128/128 SSE2 2x])
Will run 2 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
password         (john)
1g 0:00:00:06 DONE (2015-11-06 13:30) 0.1610g/s 571.0p/s 735.9c/s 735.9C/s modem..sss
Use the "--show" option to display all of the cracked passwords reliably
Session completed
root@kali:~#

Looks like it worked. So we can now use john –show option to list cracked passwords. Note that it’s a simple password that existed in the dictionary so it worked. If it wasn’t a simple password, then you would need a much bigger dictionary and a lot longer to crack it.

cracking-password-in-kali-john-the-ripper-picateshackz-4

root@kali:~# john --show /root/johns_passwd 
john:password:1000:1001::/home/john:/bin/bash

1 password hash cracked, 1 left
root@kali:~#

Now that we have completed the basics of John the Ripper and cracked a password using it, it’s possibly time to move on to bigger and more complex things.

ALSO READ  Learn to Hack Instagram utilizing Kali Linux 2017.1

John the Ripper

John the Ripper is a free password cracking software tool. Initially developed for the Unix operating system, it now runs on fifteen different platforms (eleven of which are architecture-specific versions of Unix, DOSWin32BeOS, and OpenVMS). It is one of the most popular password testing and breaking programs as it combines a number of password crackers into one package, autodetects password hash types, and includes a customizable cracker. It can be run against various encrypted password formats including several crypt password hash types most commonly found on various Unix versions (based on DESMD5, or Blowfish), Kerberos AFS, and Windows NT/2000/XP/2003 LM hash. Additional modules have extended its ability to include MD4-based password hashes and passwords stored in LDAPMySQL, and others.

 

 

It's only fair to share...Digg thisShare on FacebookShare on Google+Tweet about this on TwitterShare on LinkedInFlattr the authorShare on TumblrShare on VKShare on YummlyShare on RedditShare on StumbleUpon