REST API Testing
The backbone of modern applications, properly secured.
Comprehensive testing of RESTful APIs for authentication bypass, injection flaws, broken object-level authorization, and data exposure.
Overview
REST APIs power modern applications, from mobile backends to microservices architectures. REST API Testing provides comprehensive security assessment of your RESTful services, focusing on the vulnerabilities scanners miss—broken object-level authorization, business logic flaws, and authentication bypass that require human analysis to identify and exploit.
What We Test
Our rest api testing engagements cover these key areas:
Broken Object-Level Authorization (BOLA) across all endpoints
Authentication mechanism strength and bypass opportunities
Injection vulnerabilities (SQL, NoSQL, command, LDAP)
Mass assignment and parameter tampering
Rate limiting and resource exhaustion
Sensitive data exposure in responses and error messages
Our Approach
REST API testing requires understanding how applications consume APIs, not just the API specifications. We test from the perspective of both legitimate users and attackers attempting to abuse API functionality.
API Discovery & Mapping
Document all API endpoints through specification review (OpenAPI/Swagger), traffic analysis, and automated discovery. Identify undocumented endpoints that may lack security controls.
Authentication Analysis
Evaluate authentication mechanisms—API keys, JWT tokens, session cookies, OAuth tokens. Test for weak implementations, token prediction, and bypass opportunities.
Authorization Testing
Test every endpoint for BOLA vulnerabilities by manipulating resource identifiers. Verify that users can only access their own resources across all HTTP methods.
Input Validation Testing
Probe all input parameters for injection vulnerabilities. Test query parameters, request bodies, headers, and path parameters for SQL, NoSQL, and command injection.
Business Logic Analysis
Analyze API workflows for logic flaws—race conditions, parameter manipulation, transaction abuse, and state management issues that enable unintended behavior.
Response Analysis
Examine API responses for excessive data exposure, stack traces, internal paths, and sensitive information that aids attackers in further exploitation.
Common Findings
These are issues we frequently discover during rest api testing engagements:
Broken Object-Level Authorization
APIs that check authentication but not authorization—users can access other users' data by changing resource IDs. The most common critical API vulnerability.
Excessive data exposure
APIs return full database records when clients only need specific fields. Sensitive data exposed includes internal IDs, timestamps, and user details.
Missing rate limiting
APIs allow unlimited requests, enabling brute force attacks, enumeration, and denial of service. Particularly critical on authentication endpoints.
JWT implementation flaws
Weak signing algorithms, missing signature verification, or algorithm confusion attacks that allow token forgery or privilege escalation.
Mass assignment vulnerabilities
APIs accept and process parameters that shouldn't be user-controllable—role fields, account status, or pricing data embedded in request bodies.
Common Questions
What's the difference between BOLA and IDOR?
They're essentially the same vulnerability—accessing other users' resources by manipulating identifiers. OWASP uses BOLA (Broken Object-Level Authorization) in the API context, while IDOR (Insecure Direct Object Reference) is the traditional web application term.
Do you test versioned APIs?
Yes. We test all API versions in scope. Often older versions lack security controls present in newer versions, and attackers specifically target deprecated endpoints.
Can you test APIs with complex request bodies?
Yes. We handle complex JSON structures, nested objects, arrays, and custom serialization formats. We analyze request structure to identify all testable parameters regardless of complexity.
What if we use custom authentication?
Custom authentication mechanisms receive extra scrutiny—they're more likely to have implementation flaws than standard protocols. We'll analyze your specific implementation and test for common custom authentication vulnerabilities.
Other API Security Testing Options
GraphQL Security
Specialized testing for GraphQL APIs including introspection attacks, query complexity abuse, and authorization bypass.
SOAP/XML Services
Legacy web service testing for XML injection, SOAP action spoofing, and WS-Security implementation flaws.
OAuth/OIDC Assessment
Authentication flow testing for OAuth 2.0 and OpenID Connect implementations, including token handling and redirect vulnerabilities.
Mobile Backend APIs
Testing APIs that support mobile applications, focusing on certificate pinning bypass, API key exposure, and mobile-specific attack vectors.
Ready to Strengthen Your Defenses?
Schedule a free consultation with our security experts to discuss your organization's needs.
Or call us directly at (445) 273-2873