Penetration testing can be categorized based on the system tested, such as network, web application, mobile, or cloud environments, and the testing approach: white box, black box, or grey box. In white box testing, testers receive full access to system details like credentials and network maps, allowing deep, efficient testing. Black box testing simulates real-world attacks from an outsider’s perspective without providing any prior information, however, it is often more costly. Grey box testing provides Limited access, like login credentials,  to simulate insider risks or partial breaches. Grey box tests are often the best option since they strike a compromise between efficiency and realism.