John the Ripper

What is John the Ripper?

John the Ripper audits passwords (often CPU) for authorized hash cracking and format detection.

Complement hashcat for format conversion and smaller lab sets.

Official website: John the Ripper · Documentation

When do you use it?

• You need CPU password auditing for lab and authorized hashes.
• You are following a CYNARKS lab or authorized engagement that calls for John the Ripper.
• You already tried simpler checks and need this tool’s deeper capability.

Who uses it?

• Penetration testers
• Red teamers (authorized only)

How do you use it? (typical flow)

1. Install John the Ripper using the steps below (prefer Kali package or official installer).
2. Confirm you have authorization for the target (lab VM, own system, or written scope).
3. Run --help / man (or the Help section) to see current flags for your version.
4. Start with a safe example from Basic commands against localhost or an authorized lab target.
5. Record what you ran, what you observed, and any follow-up (filter, report, remediation).

Help & manual (like man / --help)

Every serious tool has a built-in way to look up flags. Learn these first so you are not stuck memorizing every option.

1. 1. Help

   john --help

2. 2. Man

   man john

1. Installation

2. Basic commands

1. 1. Safe example against your own lab data or localhost

   john --wordlist=wordlist.txt lab_hashes.txt

   Safe example against your own lab data or localhost

2. 2. Show help

   john --help

   List flags for your installed version (same habit as man/--help).

3. 3. Short help

   john -h

   Alternate help flag when supported.

4. 4. List all options

   --help / -h

   List all options

Options / flags

5. Useful features

• Core workflow and interface
• Reading and interpreting output
• Key configuration options
• Integrating into a professional workflow

6. Practical examples

1. Example 1: Safe example against your own lab data or localhost

   john --wordlist=wordlist.txt lab_hashes.txt

   Safe example against your own lab data or localhost

2. Example 2: Show help

   john --help

   List flags for your installed version (same habit as man/--help).

3. Example 3: Short help

   john -h

   Alternate help flag when supported.

4. Example 4: List all options

   --help / -h

   List all options

7. Important notes

• John the Ripper is used by professionals for legitimate defense, testing and research.
• Authorized targets only — labs, systems you own, or written permission.
• Prefer reading --help / man / official docs for your installed version; flags change over time.