testing-for-json-web-token-vulnerabilities

name	testing-for-json-web-token-vulnerabilities
description	Test JWT implementations for critical vulnerabilities including algorithm confusion, none algorithm bypass, kid parameter injection, and weak secret exploitation to achieve authentication bypass and privilege escalation. Use when testing jwt implementations for critical vulnerabilities including algorithm confusion, none.
domain	cybersecurity
tags	["jwt","json-web-token","algorithm-confusion","authentication-bypass","token-forgery","kid-injection","jku-attack"]
subdomain	web-application-security
version	1.0
author	oyi77
license	Apache-2.0
nist_csf	["PR.PS-01","ID.RA-01","PR.DS-10","DE.CM-01"]

Testing For Json Web Token Vulnerabilities

Overview

Cybersecurity skill for testing for json web token vulnerabilities. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "testing for json web token vulnerabilities"

• "Test JWT implementations for critical vulnerabilities including algorithm confus"

• When testing applications using JWT for authentication and session management

• During API security assessments where JWTs are used for authorization

• When evaluating OAuth 2.0 or OpenID Connect implementations using JWT

• During penetration testing of single sign-on (SSO) systems

• When auditing JWT library configurations for known vulnerabilities

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

Prerequisites

• jwt_tool (Python JWT exploitation toolkit)
• Burp Suite with JWT Editor extension
• jwt.io for decoding and inspecting JWT structure
• Understanding of JWT structure (header.payload.signature) and algorithms (HS256, RS256)
• hashcat or john for brute-forcing weak JWT secrets
• Python PyJWT library for custom JWT forging scripts
• Access to application using JWT-based authentication

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Workflow

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: ) -> :
     {k: re.findall(v, text)  k, v  IOC_PATTERNS.items()}