Application Security Testing
APIPentest.OWASP API Top 10.
443 Labs delivers REST, GraphQL, and gRPC API penetration testing to OWASP API Top 10 — covering BOLA, mass assignment, authentication bypass, rate limiting, and excessive data exposure with developer-ready findings.
REST · GraphQL · gRPC · OWASP API Top 10
Testing Methodology
Define Scope & API Reconnaissance
Identify in-scope APIs, environments, authentication methods, and testing depth. Analyse API architecture, endpoints, data flows, and integrations. Review OpenAPI/Swagger definitions and request/response schemas for undocumented endpoints and shadow API exposure.
Vulnerability Identification
Discover security flaws using manual and automated testing across authentication, authorisation (BOLA/IDOR), input validation, excessive data exposure, rate limiting, business logic, and security configuration — mapped to OWASP API Security Top 10.
Exploitation & Validation
Safely validate identified vulnerabilities to determine real-world impact. Test integrated services, third-party dependencies, and trust boundaries. Assess business logic abuse scenarios and transaction integrity weaknesses.
Reporting, Remediation & Retest
Deliver detailed findings with clear remediation guidance, reproduction steps, and impact analysis. Validate remediation of identified issues and issue a final cleared report for compliance submission.
Engagement Deliverables
Every endpoint tested.
Including the undocumented ones.
Executive Summary & API Risk Dashboard
Business-level overview of API security posture with critical findings, OWASP API Top 10 coverage, and risk prioritisation.
Technical API Penetration Test Report
Detailed findings per OWASP API category with reproduction steps, request/response examples, CVSS scores, and developer-ready remediation guidance.
Remediation Validation & Retest
Full retest of all medium, high, and critical API findings with closure evidence.
Final Cleared Report
Compliance-ready final report confirming remediation status for PCI DSS, ISO 27001, and regulatory audit submissions.
REST, GraphQL, gRPC, and WebSocket APIs tested in a single engagement
JWT, OAuth 2.0, API key, and mTLS authentication thoroughly tested
BOLA/IDOR testing across all resources — #1 cause of API breaches
OWASP API Top 10 mapped report with CVSS scoring and retest included
Why 443 Labs
The API pentest difference that finds breaches before they happen.
BOLA Testing on Every Endpoint
Broken Object Level Authorisation is the #1 OWASP API vulnerability and the cause of the majority of API data breaches. We test every accessible object endpoint — not a sample — to find IDOR vulnerabilities that scanners cannot detect.
Shadow API Discovery
We enumerate undocumented endpoints using traffic analysis, JavaScript source analysis, and fuzzing techniques. Shadow APIs often lack the authentication and rate limiting controls present on documented endpoints.
Business Logic Abuse Testing
We test workflow abuse scenarios, transaction integrity, parameter manipulation, and mass assignment vulnerabilities — the API vulnerabilities that require understanding your business logic to discover.
REST, GraphQL, and gRPC Coverage
Testing is supported across RESTful, GraphQL, and gRPC APIs. GraphQL-specific testing includes introspection abuse, query depth attacks, and resolver-level authorisation testing.
Not Sure Where to Start
We'll scope your API pentest and define the right coverage depth.
Whether you're securing a fintech API, a microservices architecture, or a public-facing SaaS platform — our testers will define the right scope, methodology, and testing depth for your use case and compliance requirements.
OWASP API Coverage
Common Questions
Do you test REST and GraphQL APIs?
Testing is supported for RESTful, GraphQL, and SOAP-based APIs, as well as gRPC and WebSocket services. Both authenticated and unauthenticated endpoints are tested as part of a comprehensive scope.
Is source code required for API testing?
Testing is primarily performed using a grey-box approach — API documentation, collections, and limited internal knowledge. White-box access enables deeper analysis, broader coverage, and shorter engagement timelines.
Do you follow a standard methodology?
Yes. Testing is aligned with the OWASP API Security Top 10 and OWASP Web Security Testing Guide (WSTG). All findings are mapped to OWASP categories with CVSS scoring.
Will testing affect production systems?
Testing is conducted in a controlled manner. High-risk tests — such as rate limiting exhaustion or mass data operations — are coordinated in advance and may be directed to a staging environment.
Do you provide remediation-ready reports?
Yes. Reports include detailed findings, reproduction steps with request/response examples, impact analysis, and developer-specific remediation guidance. Retests of all medium, high, and critical findings are included.
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OWASP API Top 10 manual testing. BOLA/IDOR on every resource. Retest included. Start your API pentest today.