jwt-cracker

Simple HS256, HS384 & HS512 JWT token brute force cracker.

Effective only to crack JWT tokens with weak secrets. Recommendation: Use strong long secrets or RS256 tokens.

Install

With npm:

npm install --global jwt-cracker

Usage

From command line:

jwt-cracker -t <token> [-a <alphabet>] [--max <maxLength>] [-d <dictionaryFilePath>] [-f]

Where:

• token: the full HS256-512 JWT token string to crack
• alphabet: the alphabet to use for the brute force (default: “abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789”)
• maxLength: the max length of the string generated during the brute force (default: 12)
• dictionaryFilePath: path to a list of passwords (one per line) to use instead of brute force
• force: force script to execute when the token isn’t valid

Requirements

This script requires Node.js version 16.0.0 or higher

Example

Cracking the default jwt.io example:

jwt-cracker -t eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ -a abcdefghijklmnopqrstuwxyz --max 6

It takes about 2 hours in a Macbook Pro (2.5GHz quad-core Intel Core i7).

Or using a list of passwords taken from https://github.com/danielmiessler/SecLists

jwt-cracker -t eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ -d darkweb2017-top10000.txt

It takes less than a second.

Contributing

Everyone is very welcome to contribute to this project. You can contribute just by submitting bugs or suggesting improvements by opening an issue on GitHub.

License

Licensed under MIT License. © Luciano Mammino.