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NoorQureshiNoorQureshi/ronin/skills/api/api-testing-checklist/SKILL.md

api-testing-checklist

Skill26 starsChanged 32 days agoMITView on GitHub

A fast, ordered methodology for assessing an API end to end — REST/GraphQL/gRPC/SOAP — so nothing gets skipped. Load when the target is an API (or recon found one), on "test this API", "checklist", methodology triage, or to confirm coverage before reporting. Signals: /api, swagger/openapi.json, GraphQL /graphql, gRPC, JSON/XML endpoints, a mobile/SPA backend.

3 other projects use a version of this.

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The file

We split this skill into the rules it gives an agent

1 rule. About 0 are common, 0 are distinctive, and 1 is very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈0

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 1

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Every endpoint × method exercised.

    line 62

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

API testing methodology (work top to bottom)

Confirm scope first (tradecraft-scope-roe). Each phase links to the skill that goes deep — load it, work its cheatsheet.md where present, and don't mark a phase failed until you've covered it (house rule: fuzz every input/context/encoding, blind/OOB). This is your coverage map.

1 · Discover & map the surface

  • Find the API: /api, subdomains, JS files (recon-js-analysis), mobile/SPA traffic (recon-content-discovery)
  • Grab the spec: swagger.json / openapi.json / GraphQL introspection / .proto — enumerate every endpoint, method, param
  • Note auth model (Bearer/JWT/API key/cookie/mTLS), versions (/v1,/v2), and content types
  • Map roles: create two accounts (and an unauth client) — you need them for access-control tests

2 · Authentication

  • Token flaws — JWT alg/kid/key confusion (web-auth-jwt), API-key leakage/predictability
  • Auth attacks — credential stuffing, weak/OTP flows, token not expiring/rotating (api-auth-attacks)
  • Unauthenticated endpoints that shouldn't be

3 · Authorization (the #1 API bug class — go deep)

  • BOLA/IDOR — swap object IDs between the two accounts on every object-taking endpoint (api-bola, web-idor)
  • BFLA — call admin/privileged functions as a low-priv user; try hidden methods (PUT/DELETE/PATCH)
  • Path/verb tampering, X-Original-URL/method override, GraphQL field-level authz

4 · Input handling & injection

  • Injection across params, JSON bodies, headers: SQLi (web-sqli), NoSQL (api-mongo-agg-facet-bypass), command (web-command-injection), SSTI (web-ssti)
  • SSRF via URL params / webhooks / "fetch from URL" (web-ssrf), XXE on XML endpoints (web-xxe)
  • Mass assignment — inject extra fields (role,isAdmin,price) (api-mass-assignment)

5 · Data exposure & business logic

  • Excessive data exposure — endpoints returning more fields than the UI shows (PII, internal flags)
  • Business-logic abuse — price/quantity tampering, negative values, replay, race conditions (web-race-conditions, web-business-logic)
  • Mass assignment → privilege/state change; parameter pollution (web-http-parameter-pollution)

6 · Rate limiting & resource consumption

  • Missing/bypassable rate limits (web-rate-limit-bypass) — brute, enumeration, cost
  • Unbounded queries / pagination abuse; GraphQL depth/alias/batch amplification

7 · Protocol specifics

  • GraphQL — introspection, batching, injection, field authz (api-graphql)
  • gRPC — reflection, message tampering (api-grpc)
  • REST/SOAP — verb tampering, content-type confusion, version drift (api-versioning); fuzz systematically (api-fuzzing)

8 · Before you report

  • Re-prove each finding from a clean session; anonymise data (reporting-triage-validation)
  • Score it (reporting-cvss-scoring), then write it up (reporting-bug-bounty-writeup)

Coverage bar

Every endpoint × method exercised; BOLA/BFLA tried across accounts on every object; injection fuzzed on every input; rate-limit and business-logic checked. A phase is failed only after that — else open.

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