jwt-cracker

Simple HS256 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>]

Where:

token: the full HS256 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)

Requirements

This script requires Node.js version 6.0.0 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).

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.