What is API penetration testing?

API penetration testing assesses the security of REST, GraphQL, SOAP, and gRPC APIs against the OWASP API Security Top 10, covering broken object-level authorisation, excessive data exposure, BOLA/IDOR, rate limiting bypasses, and authentication vulnerabilities.

Do you test JWT and OAuth 2.0 implementations?

Yes, Scyverge tests JWT and OAuth 2.0 token validation, role-based access control enforcement, token lifecycle management, and privilege escalation across API endpoints.

API Penetration
Testing

Comprehensive security testing for REST, GraphQL, SOAP, and gRPC APIs. We identify broken authorisation, excessive data exposure, injection flaws, and rate limiting gaps, with CVSS-scored findings and a free re-test included.

Request API Penetration Test All Services

OWASP API Top 10 (2023) BOLA / IDOR Testing JWT + OAuth 2.0 Free Re-Test

API Terminal

GET /api/v1/users/ 200

GET /api/v1/users/124 200

GET /api/v1/users/125 403

BOLA: Can access user 124 without auth token

POST /api/v1/admin/create 401

POST /api/v1/admin/create 403

Mass assignment: role=admin accepted

DEL /api/v1/users/126 401

GET /graphql?query={users} 200

GraphQL introspection enabled

BOLA / IDOR

JWT Weak

No Rate Limit

Data Exposure

Testing Areas

What We Test on Your APIs

Purpose-built attack scenarios for REST, GraphQL, authentication, and business logic flaws.

BOLA and IDOR Testing

We systematically test every endpoint for broken object-level authorisation by manipulating resource IDs to access other users' data across all roles.

JWT and Token Security

We test JWT implementation for weak secrets, algorithm confusion, none algorithm attacks, and improper token validation and expiration handling.

OAuth 2.0 and OIDC Assessment

We assess OAuth flows for redirect manipulation, token leakage, CSRF on callback endpoints, and scope abuse across authorisation servers.

Role-Based Access Control

We test RBAC enforcement across all API endpoints, identifying privilege escalation paths from standard user to admin roles.

Session and Token Lifecycle

We test token rotation, revocation, concurrent session handling, and whether expired or revoked tokens remain functional.

Multi-Tenant Access Control

We assess cross-tenant access in multi-tenant APIs, ensuring authenticated users cannot access data from other organisations.

SQL and NoSQL Injection

We test API parameters for SQL injection in JSON bodies, headers, and query strings, plus NoSQL injection in MongoDB and similar databases.

Command Injection

We identify OS command injection in API parameters that flow to system calls, testing both blind and direct execution scenarios.

Server-Side Request Forgery

We test API endpoints that make backend requests for SSRF vulnerabilities, including cloud metadata access and internal service enumeration.

GraphQL Query Abuse

We test GraphQL APIs for introspection disclosure, query depth attacks, circular query denial of service, and unauthorised schema access.

XML and SOAP Injection

We test SOAP APIs for XML external entity injection, XML bomb attacks, and schema-based vulnerabilities in legacy web services.

Template Injection

We identify server-side template injection in API responses that render user input through template engines like Jinja2, Freemarker, or Velocity.

Rate Limiting Bypass

We test rate limiting enforcement across authentication, password reset, and sensitive endpoints, identifying bypass techniques and missing limits.

Mass Assignment

We test whether API endpoints accept unintended parameters, allowing attackers to modify privileged fields like role, isAdmin, or pricing.

Batch Endpoint Abuse

We test batch and bulk endpoints for authorisation bypass, excessive data access, and denial of service through resource exhaustion.

Excessive Data Exposure

We identify API responses that return more data than the client needs, including hidden fields, internal IDs, and other users' information.

Payment and Transaction Logic

We test financial APIs for price manipulation, negative quantities, race conditions in transfers, and payment workflow bypasses.

Race Conditions and TOCTOU

We identify time-of-check to time-of-use vulnerabilities in API operations, testing concurrent requests against stateful operations.

Methodology

How We Run an API Penetration Test

A structured six-phase process aligned with OWASP API Security Top 10 (2023), from discovery through verified remediation.

Phase 01

API Discovery and Schema Mapping

We enumerate all API endpoints, parameters, and data flows through documentation review, traffic analysis, and automated endpoint discovery for undocumented paths.

Phase 02

Authentication and Token Analysis

We test authentication mechanisms, token lifecycle, JWT implementation, OAuth flows, and session management for bypass, forgery, and improper validation.

Phase 03

Authorisation and Access Control

We test BOLA and IDOR across every endpoint, RBAC enforcement, cross-tenant access, and privilege escalation from standard user to admin roles.

Phase 04

Input Validation and Injection

We test for SQL and NoSQL injection, command injection, SSRF, and other injection-class vulnerabilities in all API input parameters and headers.

Phase 05

Rate Limiting and Business Logic

We test rate limit enforcement, mass assignment, batch endpoint abuse, excessive data exposure, and business logic manipulation in your workflows.

Phase 06

Reporting and Free Re-Test

We deliver a CVSS-scored report with proof-of-concept evidence, OWASP API and CWE mapping. Once you remediate, we re-test all findings at no additional cost.

Who It's For

Built for API-First Businesses

SaaS and Platform Companies

API-first businesses exposing programmatic access to customers and partners, where API flaws translate directly to data breaches and customer trust erosion.

FinTech and Payment Platforms

Financial APIs handling transactions, account data, and payment flows that require PCI-DSS compliance and protection against BOLA and data exposure.

Microservices and Cloud-Native Teams

Teams running microservice architectures with internal and external APIs who need to validate inter-service trust boundaries and prevent lateral movement through API flaws.

FAQ

Questions We Get Asked Often

API penetration testing assesses the security of REST, GraphQL, SOAP, and gRPC APIs against the OWASP API Security Top 10 (2023). It covers broken object-level authorisation, excessive data exposure, BOLA and IDOR, rate limiting bypasses, authentication vulnerabilities, and injection flaws that traditional web scanners often miss.

BOLA (Broken Object-Level Authorisation) and IDOR (Insecure Direct Object Reference) are among the most critical API vulnerabilities. They allow attackers to access other users' data by manipulating resource IDs in API requests. Scyverge systematically tests for these across all API endpoints and all user roles to identify every unauthorised access path.

Yes. We test JWT implementation for weak secrets, algorithm confusion attacks, none algorithm bypass, improper token validation, and expiration handling. For OAuth 2.0, we assess authorisation flows for redirect manipulation, token leakage, CSRF on callback endpoints, and scope abuse across your authorisation server.

We need API documentation (OpenAPI/Swagger, GraphQL schema, or WSDL), valid credentials for all user roles, and a brief overview of critical functionality and business logic. If documentation is unavailable, we can perform discovery through traffic analysis and endpoint enumeration.

Typical engagements take 5 to 12 business days depending on API complexity, number of endpoints, and number of user roles. GraphQL APIs may require additional time for query depth analysis. We provide a precise timeline after initial scoping discussions.

API PenetrationTesting