hunt-jwt-crypto
Hunt JWT cryptographic failures — alg:none signature-stripping and RS256→HS256 key-confusion that let an attacker forge a token for any identity (e.g. an admin) without knowing a secret. Use when the app authenticates with a JSON Web Token (an `eyJ...` Bearer token in the Authorization header, a cookie, or a login response). This skill OWNS JWT signature/crypto forgery (alg:none, key confusion, kid/jku header injection); hunt-ato covers JWT as one ATO path, hunt-auth-bypass covers SSO/SAML token trust, hunt-api-misconfig covers non-crypto JWT handling. Critical when a forged token grants access to another user's data or an admin-only endpoint.
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Critical
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Security
3 findings: 2 critical severity, 1 high severity. Installing this skill is not recommended: please review these findings carefully if you do intend to do so.
E004: Prompt injection detected in skill instructions.
What this means
Detected a prompt injection in the skill instructions. The skill contains hidden or deceptive instructions that fall outside its stated purpose and attempt to override the agent’s safety guidelines or intended behavior.
Why it was flagged
This skill contains explicit, actionable, step-by-step instructions and tooling to forge JWTs (alg:none, RS256→HS256 key confusion, kid/jku/jwk injections, expiry manipulation) and to escalate to admin actions, enabling unauthorized account takeover and data access.
E006: Malicious code pattern detected in skill scripts.
What this means
Detected high-risk code patterns in the skill content — including its prompts, tool definitions, and resources — such as data exfiltration, backdoors, remote code execution, credential theft, system compromise, supply chain attacks, and obfuscation techniques.
Why it was flagged
The skill explicitly teaches how to forge JWTs (alg:none, RS256→HS256 key-confusion, kid/jku/jwk injections) and directs using those forged tokens to access admin endpoints and perform destructive actions (e.g. deleting users), showing clear intent to bypass authentication with concrete, runnable mechanisms.
W007: Insecure credential handling detected in skill instructions.
What this means
The skill handles credentials insecurely by requiring the agent to include secret values verbatim in its generated output. This exposes credentials in the agent’s context and conversation history, creating a risk of data exfiltration.
Why it was flagged
The skill's examples and commands require embedding bearer JWTs (and using keys as HMAC secrets) directly on the command line or in forged requests (e.g., "jwt_tool <token>" and re-signing with a PEM as the secret), which forces an agent to handle/output secret token values verbatim and creates an exfiltration risk.
- Repository
- elementalsouls/Claude-BugHunter
- Commit
d4b54e1
- Audited
- Security analysis
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