This cheat sheet briefly references some of the most commonly used John the Ripper commands, along with a brief description and practical examples to illustrate their use. Whether you’re a seasoned professional looking to brush up on your password-cracking skills or a newcomer eager to explore the possibilities of this powerful tool, you’ll find valuable insights and shortcuts here.
Table of Contents
Installation
John the Ripper is included in many Linux distributions and can be installed easily. Here are commands for popular distributions:
| Distribution | Command |
|---|---|
| Debian/Ubuntu | sudo apt-get install john |
| CentOS/Fedora | sudo yum install john (CentOS 7 and below), sudo dnf install john (Fedora and CentOS 8+) |
| NixOS | nix-env -iA nixos.john |
Usage
| Task | Command |
|---|---|
| Basic password cracking | john passwd_file |
| Show cracked passwords | john --show passwd_file |
| Use specific wordlist | john --wordlist=path/to/wordlist.txt passwd_file |
| Crack using rules | john --rules passwd_file |
| Specify hash type | john --format=md5crypt passwd_file |
| List available formats | john --list=formats |
Examples
Cracking Unix passwords:
john --format=descrypt /etc/shadowUsing a custom wordlist:
john --wordlist=/usr/share/john/password.lst --rules /etc/shadowForce using OpenMP for parallel processing:
OMP_NUM_THREADS=4 john --format=md5crypt /etc/shadowWrapping Up
This cheat sheet has outlined the tool’s flexibility and power for everything from simple password cracking to complex hash-breaking tasks. Mastering John the Ripper can significantly enhance your understanding of system vulnerabilities and improve your defensive cybersecurity strategies. Continue to practice, explore advanced options, and share your experiences to help enrich the community’s collective knowledge.
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References
John the Ripper Official Site: Offers comprehensive resources, including documentation, tutorials, and downloads for John the Ripper. Visit the Official John the Ripper Site
