Cyber Defense
API security assessment services matter because your API has no interface to hide behind. There is no front end quietly enforcing which button a user may press. There is a URL, a token, and whatever your code decides to return. Most serious API findings are one missing check away from every customer record.
We enumerate the real surface, not the documented one: the endpoints in your specification, the ones your mobile and web clients call, the versions you deprecated but never switched off, and the internal service routes that ended up reachable. Then we test each of them as every role you have, and as no role at all.
The assessment follows the OWASP API Security Top 10 as a floor rather than a ceiling: broken object-level authorisation, broken function-level authorisation, excessive data exposure and unrestricted resource consumption are where the real findings cluster. Where the API serves an app, pair this with mobile app security testing; where it fronts cloud infrastructure, with cloud security testing.
Why you need it
01 / 06Every endpoint that takes an identifier has to independently verify that this caller may touch that object. One handler that forgets is enough. This is the single most common critical API finding, and it is invisible to any tool that does not know which records belong to whom.
Front ends filter for display; APIs frequently serialise the whole object. Password hashes, internal flags, other users' email addresses and full audit trails arrive in a response that renders as one harmless line in the interface.
v1 is deprecated in the documentation and still routed in production, without the authorisation logic that was added in v2. Shadow and zombie endpoints are found by enumeration, not by reading the specification.
Without per-endpoint rate limiting and resource controls, an API is a data-extraction service. Enumeration of identifiers, credential stuffing and expensive GraphQL queries all scale in a way that no human interface allows.
Instrument
02 / 06What the automated pass reports about an API, and what a tester confirms once two accounts are in play.
What we deliver
03 / 06Specification review where an OpenAPI, GraphQL schema or gRPC definition exists, plus discovery of what actually answers: undocumented routes, retired versions still live, debug and administrative endpoints, and the calls we recover from your own clients and JavaScript bundles.
Credential and token flows end to end: OAuth 2.0 and OpenID Connect implementation, JWT signature validation and algorithm confusion, token lifetime and revocation, refresh handling, API key scoping, and whether an expired or forged token is actually rejected.
The core of the engagement. Each endpoint is called as each role and as each of two peer accounts, with identifiers swapped, to establish whether the server enforces ownership and privilege on every path, including nested resources and bulk operations.
What each response actually contains versus what the consumer needs, and what each request body is allowed to set. Fields like role, tenant, isAdmin and balance that bind automatically from JSON are tested for direct assignment.
SQL and NoSQL injection, command injection, server-side request forgery through URL parameters, XML external entities, deserialisation, and GraphQL-specific abuse including introspection, batching and deeply nested queries.
Per-endpoint and per-account limits, whether they can be evaded by rotating headers or credentials, pagination limits, file upload constraints, and the query that makes your database do a hundred times the work of a normal request.
How we run it
04 / 06Environments, specification files where they exist, and at minimum two accounts per role so that cross-account authorisation can be tested at all. Rules of engagement, testing windows and an escalation contact are agreed in writing.
Week 0The full reachable surface: specification-driven for what is documented, and traffic capture, client analysis and fuzzing for what is not. The map we produce is frequently the first complete inventory the client has had.
Days 1-2Schema-driven and template-driven checks with Nuclei and Burp Suite scanning to establish breadth. Useful for coverage; not the finding set.
Day 2Authorisation matrices executed request by request across accounts and roles, token manipulation, mass-assignment and data-exposure review, injection, and resource-consumption abuse. Confirmed findings are chained to establish what the combination reaches.
Days 3-7A report with the request and response for every finding, ranked by data reached, delivered in a working session with the engineers who own the endpoints. Re-test and closure once fixes ship.
Days 8-10, then on your scheduleKey benefits
05 / 06Including the versions and routes that were not in the specification. Several clients have switched off more surface than they patched.
The class of bug that leaks every customer record is tested per endpoint, per role, per account, and once fixed, re-tested the same way.
A dated assessment against the OWASP API Security Top 10, with verified remediation, satisfies the API section of enterprise due diligence without further negotiation.
Tools we use
06 / 06No “latest tech tools”. These are the ones your report will cite, alongside the manual work that a tool cannot do for you.
Interception and testing
Discovery and fuzzing
Protocol-specific
Code and schema
Methodology
Why Aphelion
SharedDarshap Nayak, formerly of KPMG, holds a master’s degree in cybersecurity and more than seven years in security operations. Jaimin Somani brings fifteen-plus years of academic and hands-on VAPT. Hemang Desai is an ICT network specialist from Australia. You will meet them, not a logo.
Meet the teamEvery finding arrives with the reproduction steps, the affected asset and the fix, ranked by what it actually reaches in your environment, not by a CVSS number copied from a scanner. You get the report and the raw output, not a summary of a summary.
See how we testAhmedabad and Sharjah, working the same methodology on the same tooling. Indian data-residency requirements and UAE delivery are both ordinary here, and the AphelioNYX AD Pen-Test module runs entirely inside your perimeter when regulation says it must.
The platformInvent a statistic to make a slide land. Publish your name as a client without written permission. Print an award badge nobody awarded. Founded in 2024. We say so, and we attribute experience to the people who have it.
Ask us anythingAcross the globe, and across eight industries. We name a client only with their written permission.
AphelioNYX is SOC 2, ISO and GDPR compliant; attestations are available on request under NDA. We would rather hand you the report than print a badge.
Questions
FAQNext door
RelatedA personalised walkthrough and a free readiness assessment against the frameworks you are actually being asked for. Pick a time that suits you, or write to us. We reply within one business day.