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Api security testing

Skill charlieviettq/awesome-agent-skill/.cursor/skills/security-appsec/api-security-testing

Curated skill pack for LLM agents in engineer and science workflow (Cursor & Claude ready).

Install
npx -y skills add charlieviettq/awesome-agent-skill --skill api-security-testing

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

  • 22 stars22 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Security testing checklist for HTTP APIs—authn/z, input validation, rate limits, sensitive data exposure, and common OWASP API issues. Use when reviewing or testing REST/GraphQL endpoints before release. Triggers: "API security", "pen test API", "OWASP API", "auth test", "security test".

SKILL.md

2.0 KB, 375 tokens by cl100k_base, as published. Nobody here has run it

API security testing

Preconditions

  • Test in non-production unless explicitly authorized.
  • Use dedicated test accounts; never real customer PII in payloads.

Test matrix (prioritized)

Authentication and session

  • Missing/invalid token rejected (401)
  • Expired or revoked credentials rejected
  • Session fixation / cookie flags (HttpOnly, Secure, SameSite) where applicable

Authorization

  • Horizontal: user A cannot access user B's resource IDs
  • Vertical: non-admin cannot invoke admin routes
  • IDOR on path/query/body identifiers

Input and abuse

  • Oversized payloads rejected
  • Injection surfaces parameterized (SQL, command, template)
  • Rate limiting on auth and expensive endpoints

Data exposure

  • Errors do not leak stack traces or secrets in prod-like config
  • Responses omit internal fields (tokens, hashes, full PAN)
  • Pagination does not bypass auth filters

Transport and config

  • HTTPS enforced; HSTS where applicable
  • CORS not * with credentials
  • Security headers on API gateway if present

Web-facing surfaces (when API serves or pairs with UI)

  • CSP or explicit script policy documented
  • CSRF protection on cookie-based mutations
  • Clickjacking headers (X-Frame-Options or CSP frame-ancestors) where relevant
  • File upload: type/size limits, virus scan hook if required by policy

Reporting

For each finding: endpoint, steps, impact, severity, remediation, retest status.

Boundaries

  • Defensive testing only; no unauthorized production scanning.
  • For deep pen-test, engage formal AppSec process.

Keep looking

Skills are one crate of 328,083. Ordering is by how many stacks a row turns up in, so the top of any crate is what has actually been picked rather than what has the most stars.