API Penetration Testing
Thorough security assessments of REST, GraphQL, and SOAP APIs that identify authentication flaws, authorisation bypasses, injection vulnerabilities, and business logic weaknesses across your entire API ecosystem.
Overview
APIs are the backbone of modern digital infrastructure, powering mobile applications, microservices architectures, third party integrations, and partner ecosystems. As organisations increasingly rely on APIs to exchange sensitive data and execute critical business functions, the API attack surface has become a primary target for sophisticated adversaries. Our API penetration testing service delivers comprehensive security assessments that evaluate every aspect of your API ecosystem, from authentication and authorisation mechanisms to data validation, rate limiting, and business logic integrity.
Our certified security professionals test APIs across all common architectures including REST, GraphQL, SOAP, and gRPC. We go beyond the OWASP API Security Top 10 to identify complex vulnerabilities such as broken object level authorisation, mass assignment flaws, and server side request forgery that can lead to complete data compromise.
Our Assessment Methodology
API Discovery and Mapping
- Enumerate all API endpoints through documentation, traffic analysis, and fuzzing
- Map authentication flows, token lifecycles, and session management mechanisms
Authentication and Authorisation Testing
- Test OAuth 2.0, JWT, and API key implementations for bypass vulnerabilities
- Evaluate broken object level authorisation across all resource endpoints
Input Validation and Injection Testing
- Test for SQL injection, NoSQL injection, and command injection via API parameters
- Evaluate GraphQL queries for depth attacks, batching abuse, and introspection exposure
Business Logic and Rate Limiting
- Identify business logic flaws that allow workflow manipulation or financial fraud
- Test rate limiting and throttling controls against brute force and enumeration attacks
API Discovery and Mapping
- Enumerate all API endpoints through documentation, traffic analysis, and fuzzing
- Map authentication flows, token lifecycles, and session management mechanisms
- Identify API versioning, deprecated endpoints, and undocumented functionality
- Analyse OpenAPI, Swagger, and GraphQL schema definitions for exposure risks
Authentication and Authorisation Testing
- Test OAuth 2.0, JWT, and API key implementations for bypass vulnerabilities
- Evaluate broken object level authorisation across all resource endpoints
- Assess function level access controls and role based permission enforcement
- Test for token manipulation, replay attacks, and session fixation vulnerabilities
Input Validation and Injection Testing
- Test for SQL injection, NoSQL injection, and command injection via API parameters
- Evaluate GraphQL queries for depth attacks, batching abuse, and introspection exposure
- Assess file upload endpoints for unrestricted content types and path traversal
- Test for server side request forgery and XML external entity injection
Business Logic and Rate Limiting
- Identify business logic flaws that allow workflow manipulation or financial fraud
- Test rate limiting and throttling controls against brute force and enumeration attacks
- Evaluate mass assignment vulnerabilities and excessive data exposure risks
- Assess error handling for information disclosure and stack trace leakage
Key Outcomes
API Inventory
Complete catalogue of all API endpoints with authentication requirements and data sensitivity classifications
Access Control Validation
Thorough assessment of authorisation boundaries ensuring proper data isolation between users and roles
Data Flow Security
Evaluation of sensitive data handling across API requests, responses, and error conditions
Integration Security
Assessment of third party API integrations, webhooks, and callback mechanisms for security weaknesses
API Inventory
Complete catalogue of all API endpoints with authentication requirements and data sensitivity classifications
Access Control Validation
Thorough assessment of authorisation boundaries ensuring proper data isolation between users and roles
Data Flow Security
Evaluation of sensitive data handling across API requests, responses, and error conditions
Integration Security
Assessment of third party API integrations, webhooks, and callback mechanisms for security weaknesses
Deliverables
API Security Assessment Report with CVSS scored findings and attack narratives
API Endpoint Inventory with authentication and authorisation mapping
Authentication and Authorisation Deep Dive Report
Business Logic Assessment with workflow manipulation analysis
Executive Summary with risk overview and strategic recommendations
Remediation Verification Report following retesting engagement
Ready to Get Started?
Protect your APIs from sophisticated attacks that target the backbone of your digital infrastructure. Our specialists deliver comprehensive assessments that secure your entire API ecosystem.