03 // API Security

Your APIs Are Exposed. Most Businesses Don't Realise Until It's Too Late.

We test your REST and GraphQL APIs for the vulnerabilities that lead to data breaches, unauthorised access, and service disruption.

// The Risk

Why API Security Is Critical

APIs power everything — your mobile app, your integrations, your SaaS platform, your internal tools. They're also the most attacked surface in modern applications.

Unlike web pages, APIs don't have a visible UI. That makes vulnerabilities harder to spot and easier to exploit at scale. An attacker with a single API key or a broken endpoint can extract your entire database in minutes.

The OWASP API Security Top 10 exists for a reason. Most APIs we test fail on at least 3 of the 10 categories.

// Testing Scope

What We Test

Authentication & Authorisation

  • Broken Object Level Authorisation (BOLA)
  • Broken Authentication — weak token handling
  • Broken Function Level Authorisation
  • API key management and exposure

Data Exposure

  • Excessive data exposure in responses
  • Mass assignment vulnerabilities
  • Sensitive data in headers or errors

Input & Injection

  • SQL and NoSQL Injection
  • Command injection via API inputs
  • Server-Side Request Forgery (SSRF)

Rate Limiting & Abuse

  • Missing rate limiting on sensitive endpoints
  • Resource exhaustion attacks
  • Lack of pagination leading to data dumps

Configuration

  • CORS misconfiguration
  • Verbose error messages
  • Exposed Swagger/OpenAPI in production

GraphQL-Specific

  • Introspection enabled in production
  • Query depth and complexity attacks
  • Batching attacks
  • Field-level authorisation bypass
// Case Study

Real-World Example

A fintech startup asked us to test their payment processing API before going live. We found:

CRITICAL

Broken Object Level Authorisation

By changing the transaction_id parameter, any authenticated user could view any other user's transaction history — including amounts, recipients, and account details.

CRITICAL

Missing rate limiting on OTP endpoint

An attacker could brute-force the 6-digit verification code in under 15 minutes.

HIGH

Excessive data exposure

The /api/users/me endpoint returned the user's full record including hashed password, internal role flags, and database ID.

All three were fixed within a week with our remediation guidance. The API launched on schedule.

// Deliverables

What You Get

API Security Report

Every finding with severity, proof-of-concept requests/responses, and business impact.

OWASP API Top 10 Coverage

Mapped results showing which categories were tested.

Endpoint-by-Endpoint Analysis

Exactly which endpoints, methods, and parameters are affected.

Framework-Specific Remediation

Guidance specific to Express, ASP.NET, Django, Laravel, etc.

Postman/cURL Collection

Reproducible proof-of-concept requests your developers can use.

Free Retest

We verify your fixes and issue a clean report.

Your API Is Only as Secure as Its Weakest Endpoint

We'll test every endpoint, every method, every parameter. You'll know exactly where you stand.

Fixed pricing from £95 · Free retest included · UK-based