Password Cracking with John the Ripper

In today's blog, I am going to show you the password cracking tool John the Ripper.

John the Ripper is a free, open-source password cracking software tool, originally developed for the Unix operating system and now running on fifteen different platforms. This tool is also helpful for password recovery — if you forget your password, you can recover it with this tool. It helps crack passwords stored on a computer in hash form. John the Ripper is popular because of its dictionary attacks and is mainly used in brute-force attacks.

John the Ripper is pre-installed in Kali Linux, both as a command-line tool and with a graphical interface. You can also download it manually.

Proof of concept: open Kali Linux, click Applications, then the password cracking option, then John the Ripper's command-line tool.

First, add a new user account (in this example, "lucifer"). Check the user's password in the shadow file — run cat /etc/passwd and you can see the username lucifer with its encrypted password.

Create a text file and copy the shadow password entry into it, then open that text file with the John tool.

Decrypt the password with the command: john password.txt — after pressing enter, it decrypts the passwords listed in the shadow file. Use john --show password.txt to display the decrypted password.

Thanks For Reading.