MCPInstall

api-auth-and-jwt-abuse

API authentication and JWT abuse playbook. Use when testing bearer tokens, API keys, claim trust, header spoofing, rate limits, and API auth boundary weaknesses.

Installs
3.8K
Last 24h
+16
Trending rank
#6738
Security
Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/yaklang/hack-skills --skill api-auth-and-jwt-abuse
  1. 01

    Install

    Run the command in your project. The CLI asks which agents to install for.

  2. 02

    Describe the task

    Ask your agent for something this skill covers. It loads api-auth-and-jwt-abuse automatically when relevant.

  3. 03

    Review the result

    The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

SKILL: API Auth and JWT Abuse — Token Trust, Header Tricks, and Rate Limits

AI LOAD INSTRUCTION: Use this skill when APIs rely on JWT, bearer tokens, API keys, or weak request identity signals. Focus on token trust boundaries, claim misuse, header spoofing, and rate-limit bypass.

1. TOKEN TRIAGE

Inspect:

  • alg, kid, jku, x5u
  • role, org, tenant, scope, or privilege claims
  • issuer and audience mismatches
  • reuse of mobile and web tokens across products

2. QUICK ATTACK PICKS

PatternFirst Test
alg:none acceptanceunsigned token with trailing dot
RS256 confusionswitch to HS256 using public key as secret
kid lookup trustpath traversal or injection in kid
remote key fetch trustattacker-controlled jku or x5u
weak secretoffline crack with targeted wordlists

3. HIDDEN FIELDS AND BATCH ABUSE

Mass assignment field picks

role
isAdmin
admin
verified
plan
tier
permissions
org
owner

Rate limit and batch abuse picks

X-Forwarded-For: 1.2.3.4
X-Real-IP: 5.6.7.8
Forwarded: for=9.9.9.9

GraphQL or JSON batch abuse candidates:

  • arrays of login mutations
  • bulk object fetches with varying IDs
  • repeated password reset or verification calls in one request

4. RATE LIMIT BYPASS FAMILIES

X-Forwarded-For
X-Real-IP
Forwarded
User-Agent rotation
Path case / slash variants

5. NEXT ROUTING

  • For GraphQL batching and hidden parameters: graphql and hidden parameters
  • For default credential and brute-force planning: authentication bypass
  • For full JWT and OAuth depth: jwt oauth token attacks
  • For OAuth or OIDC configuration flaws in browser and SSO flows: oauth oidc misconfiguration
  • For credentialed browser reads and origin trust bugs: cors cross origin misconfiguration

FAQ

What does the api-auth-and-jwt-abuse skill do?

API authentication and JWT abuse playbook. Use when testing bearer tokens, API keys, claim trust, header spoofing, rate limits, and API auth boundary weaknesses.

How do I install api-auth-and-jwt-abuse?

Run npx skills add https://github.com/yaklang/hack-skills --skill api-auth-and-jwt-abuse in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/api-auth-and-jwt-abuse/ (personal) or .claude/skills/api-auth-and-jwt-abuse/ (project).

Which AI agents can use api-auth-and-jwt-abuse?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is api-auth-and-jwt-abuse safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains api-auth-and-jwt-abuse?

It is published by yaklang in yaklang/hack-skills. It has 3,791 recorded installs.

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