jwt_bruteforce
Bruteforce HS256/HS384/HS512 JWT secrets using common or custom wordlists to test token security and identify weak keys.
Instructions
Bruteforce the secret for HS256/HS384/HS512 JWTs using a common wordlist or a custom one.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| token | Yes | ||
| wordlist | No |
Implementation Reference
- server.py:93-129 (handler)The jwt_bruteforce tool handler, decorated with @server.tool() for registration. Implements JWT secret bruteforce for HS256/HS384/HS512 algorithms using a provided or default wordlist of common secrets. Parses the token, recomputes signatures with each secret, and checks for match.
@server.tool() def jwt_bruteforce(token: str, wordlist: Optional[list] = None) -> dict: """Bruteforce the secret for HS256/HS384/HS512 JWTs using a common wordlist or a custom one.""" import hmac import hashlib import base64 import json import time # Default wordlist (short for demo; in production, use a large list) common_secrets = [ 'secret', 'password', '123456', 'admin', 'jwtsecret', 'letmein', 'qwerty', 'iloveyou', 'welcome', 'monkey', 'abc123', '1q2w3e4r', 'test', 'changeme', 'default', 'passw0rd', 'supersecret', 'trustno1', 'hunter2', 'root' ] secrets = wordlist if wordlist else common_secrets try: header_b64, payload_b64, signature_b64 = token.split(".") def b64decode(data): rem = len(data) % 4 if rem: data += '=' * (4 - rem) return base64.urlsafe_b64decode(data.encode()) def b64encode(data): return base64.urlsafe_b64encode(data).rstrip(b'=').decode() header = json.loads(b64decode(header_b64)) alg = header.get("alg", "").upper() if alg not in ["HS256", "HS384", "HS512"]: return {"error": f"Bruteforce only supported for HS256/HS384/HS512, got {alg}"} hash_alg = {"HS256": hashlib.sha256, "HS384": hashlib.sha384, "HS512": hashlib.sha512}[alg] signing_input = f"{header_b64}.{payload_b64}".encode() for secret in secrets: sig = hmac.new(secret.encode(), signing_input, hash_alg).digest() sig_b64 = b64encode(sig) if sig_b64 == signature_b64: return {"result": "success", "secret": secret} return {"result": "not found", "tested": len(secrets)} except Exception as e: return {"error": str(e)}