Skip to main content
API pentest

API penetration testing

APIs fail most often at authorisation, and those flaws can't be found with a single token. We test your REST and GraphQL APIs across multiple roles and tenants, mapped to the OWASP API Security Top 10, to find gaps in object- and function-level access control.

Scope

What we test

Scope follows the OWASP API Security Top 10 (2023). The work that finds the most, and is skipped most often, is authenticated testing across roles and tenants. It is the only way to find broken object- and function-level authorisation. We ask for your OpenAPI/Swagger spec so we can cover nearly every route (a missing spec is a finding in itself).

Typical scope
  • Broken Object Level Authorization (BOLA / IDOR) across tenants and roles
  • Broken Function Level Authorization (BFLA) via role and method swaps
  • Broken Object Property Level Authorization: mass assignment and excessive data exposure
  • Authentication, unrestricted resource consumption and sensitive business flows
  • Injection, SSRF and security misconfiguration
  • GraphQL specifics: introspection, batching, nested-query DoS and error disclosure
How we work

Grey-box, authenticated, multi-role

Grey-box is the cost-effective norm: you supply the spec and test accounts for each role. The testing is manual-first, because scanners catch misconfiguration and known CVEs but miss the authorisation and business-logic flaws behind most API risk.

  1. 1

    Scoping & accounts

    We agree boundaries and collect multiple accounts across roles and tenants, plus your OpenAPI/Swagger spec.

  2. 2

    Endpoint inventory

    We map every route and operation from the spec and live traffic, and flag any gaps in the spec.

  3. 3

    Authentication & authorisation probing

    We test object- and function-level access control across roles and tenants, where most API risk sits.

  4. 4

    Input, injection & business-logic abuse

    We test injection, SSRF, resource consumption and abuse of sensitive business flows with proof of concept.

  5. 5

    Reporting & free re-test

    You get a prioritised report with request/response evidence; we re-test fixed issues at no extra charge, within the window set in the Statement of Work.

Deliverables

What you receive

The same depth as our sample report, whose worked finding happens to be a cross-tenant IDOR in an API (CWE-639, CVSS 3.1). Every finding comes with the evidence needed to reproduce and fix it.

What you get
  • Executive summary and overall risk posture
  • Each finding: description, impact, evidence, steps to reproduce and remediation
  • Proof of concept as request/response pairs
  • Severity scored with CVSS 3.1 and translated into business risk
  • References to the OWASP API Security Top 10 (2023) and CWE
  • Free re-test of remediated issues, within the window set in the SoW
Methodology & standards

Grounded in the OWASP API Security standards

OWASP API Top 10 (2023)OWASP WSTG-APIT-01OWASP ASVS 5.0PTESCVSS 3.1CWE

Coverage maps to the OWASP API Security Top 10 (2023); GraphQL testing also follows OWASP WSTG-APIT-01 (Testing GraphQL). Authorisation findings (BOLA, BFLA, object-property) need several accounts across roles and tenants, because a single token cannot reveal them. Findings are scored with CVSS 3.1.

Test your API.

Send us your OpenAPI/Swagger spec and a couple of test accounts. We'll scope the engagement, agree the rules with you and deliver the report under NDA. The first consultation is free.