Penetration testing, or pen testing, is a practice of ethical hacking deployed by companies that wish to put the performance of their cybersecurity teams and tools under scrutiny. Pen testing can be performed by in-house experts or by employing external ethical hackers.
Pen testing types are categorized by target, and by approach. In terms of target, pentesting types include network services, web applications, social engineering, client-side, wireless, and physical penetration testing. In terms of approach, the most common types of penetration testing include black box, white box, blue team, and red team pen tests.