API Penetration Testing Services

A caller changes a resource ID in the request – swap your order number for someone else's – and gets back data that isn't theirs. Automated scanners miss this because the flaw is in the business logic, not the protocol.

How we test it: We map every resource-based endpoint and systematically test whether ID or token substitution returns another user's data. It's the most common critical finding in our API pentest services.

JWTs (JSON Web Tokens) prove who you are to an API. Weak implementations let attackers forge them, either by confusing the server about which algorithm to use or by claiming the token needs no signature at all.

How we test it: We attempt algorithm confusion attacks and signature bypass techniques against every token-authenticated endpoint, then confirm the server rejects tokens it should never accept.

If an API passes request parameters straight to the data model without filtering, a caller can write to fields they shouldn't – account role, subscription tier, verified status – by adding an extra parameter to a normal request.

How we test it: We send requests with additional fields beyond the documented spec and check whether the server silently accepts and stores them.

When an API accepts a URL as input and fetches it server-side, an attacker can point it at internal services like admin panels, cloud metadata endpoints, or internal databases. They aren't meant to be reachable from outside.

How we test it: We identify every parameter that accepts URLs or hostnames and attempt to route requests to internal address ranges. SSRF via API endpoints is a consistent focus of our API pen testing services.

Without request limits, any endpoint that takes a credential, an email, or a user ID can be hit thousands of times automatically. This enables password brute-force, account enumeration, and server overload.

How we test it: We run high-volume request sequences against login, password reset, and data-fetch endpoints and record whether any throttling or blocking is applied.

Introspection is a GraphQL feature that returns your full schema on request – every type, field, and relationship. Useful in development, in production, it gives an attacker a complete map of your data model before they've found a single vulnerability.

How we test it: We query the introspection endpoint and review what is returned. We also check whether disabling introspection was done correctly, since partial blocks are easily bypassed.

API responses often return far more than the interface shows – internal IDs, hashed passwords, status flags, metadata. The frontend filters what's displayed, but the full payload is visible to anyone inspecting the network request.

How we test it: We review every response body and flag fields that have no legitimate client-side purpose. Each one is documented with the endpoint, field name, and risk.