Pentesting for APIs and Best Practices

This HackerOne report describes a methodology-driven approach to API penetration testing (PTaaS), catalogs common API vulnerabilities (broken object/function-level authorization, broken authentication including JWT weaknesses, mass assignment, excessive data exposure, injection), and provides best practices for scoping and tester matching. It includes a high-impact case study where an SQL injection in an automotive vendor allowed researchers to bypass authentication and remotely control vehicle devices, demonstrating the real-world impact of exposed API flaws and the value of regular, specialized pentesting.