api-auth-and-jwt-abuse

Original：🇺🇸 English

Translated

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

1installs

Sourceyaklang/hack-skills

Added on2026-04-09

NPX Install

npx skill4agent add yaklang/hack-skills api-auth-and-jwt-abuse

SKILL.md Content

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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

Pattern	First Test
`alg:none` acceptance	unsigned token with trailing dot
RS256 confusion	switch to HS256 using public key as secret
`kid` lookup trust	path traversal or injection in `kid`
remote key fetch trust	attacker-controlled `jku` or `x5u`
weak secret	offline crack with targeted wordlists

3. HIDDEN FIELDS AND BATCH ABUSE

Mass assignment field picks

text

role
isAdmin
admin
verified
plan
tier
permissions
org
owner

Rate limit and batch abuse picks

text

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

text

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

api-auth-and-jwt-abuse

NPX Install

Tags

SKILL.md Content

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

1. TOKEN TRIAGE

2. QUICK ATTACK PICKS

3. HIDDEN FIELDS AND BATCH ABUSE

Mass assignment field picks

Rate limit and batch abuse picks

4. RATE LIMIT BYPASS FAMILIES

5. NEXT ROUTING