John the Ripper: The Basics

John the Ripper is a well-known, well-loved, and versatile hash-cracking tool. It combines a fast cracking speed with an extraordinary range of compatible hash types.

Learning Prerequisites

For maximum benefit, we recommend you attempt this room after the first three introductory rooms about cryptography.

• Cryptography Basics
• Public Key Cryptography Basics
• Hashing Basics

There are no other learning prerequisites except basic command line abilities.

Learning Objectives

Upon the completion of this room, you learn about using John for:

• Cracking Windows authentication hashes
• Crack /etc/shadow hashes
• Cracking password-protected Zip files
• Cracking password-protected RAR files
• Cracking SSH keys

Starting with Task 4, you need to apply either on the attached VM, the AttackBox, or your own system. For your convenience, you can download the required task files as a single Zip file from this task by pressing the Download Task Files button below.