A contract penetration tester assesses the effectiveness of security for a computer network, website, software, or application. You perform your duties on a contract basis and work with various clients. A penetration tester finds, defines, and tries to exploit a vulnerability in their client’s cybersecurity system. In this career, your responsibilities not only include hacking into your client’s network or system, but also reporting on the potential vulnerability and helping the client improve their practices so that they can protect themselves against such a cyber threat when an actual hacker tries to penetrate their defenses.