Basic Usage

Learn the fundamental commands and operations of John the Ripper

John the Ripper is a powerful password cracking tool with a wide range of capabilities. This section covers the fundamental operations and commands to get you started.

Running John the Ripper

Basic Syntax

The basic syntax for running John the Ripper is:

john [options] [password-files]

Where:

  • options are the command-line flags that control John's behavior
  • password-files are the files containing the password hashes to be cracked

Simple Example

To crack a password file using default settings:

john password.txt

This command will:

  1. Auto-detect the hash format in the file
  2. Use the default wordlist (usually located at /usr/share/john/password.lst)
  3. Apply default rules to the wordlist
  4. Display cracked passwords as they are found

Password File Formats

John the Ripper supports various password file formats:

Unix-style Password Files

Traditional Unix password files have the format:

username:$hashtype$salt$hash:UID:GID:GECOS:home:shell

Example:

user:$1$salt$hash:1000:1000:User:/home/user:/bin/bash

Simple Hash Lists

For simple hash lists, each line contains a single hash:

5f4dcc3b5aa765d61d8327deb882cf99
d8578edf8458ce06fbc5bb76a58c5ca4

Hash:Salt Format

For formats requiring separate salt values:

hash:salt

Viewing Results

Showing Cracked Passwords

To view passwords that have already been cracked:

john --show password.txt

This displays usernames and their corresponding cracked passwords.

Viewing Session Status

To check the status of a running session:

john --status

This shows statistics about the current cracking session, including:

  • Time elapsed
  • Passwords tried
  • Cracking speed (passwords per second)
  • Estimated time remaining

Stopping and Resuming

Stopping a Session

To stop a running session, press Ctrl+C. John will save its progress automatically.

Resuming a Session

To resume a previously stopped session:

john --restore

This continues from where the previous session left off, using the same settings and progress.

Basic Wordlist Mode

Using a Custom Wordlist

To use a specific wordlist for cracking:

john --wordlist=wordlist.txt password.txt

This tries each word in the specified wordlist against the hashes in the password file.

Applying Rules to Wordlists

To apply mangling rules to a wordlist:

john --wordlist=wordlist.txt --rules password.txt

This applies transformation rules (like capitalization, adding numbers, etc.) to each word in the wordlist.

Next Steps

After mastering the basic usage, you can explore: