Definition
Penetration testing, often shortened to pen testing or pentest, is a simulated cyberattack against a computer system, network, or web application to identify security vulnerabilities. Ethical hackers perform these tests by actively attempting to exploit weaknesses in the same way a malicious attacker would. This proactive approach is crucial for understanding an organization's actual security posture and identifying exploitable flaws before they can be leveraged by adversaries. For instance, a pen test might involve trying to gain unauthorized access to sensitive data by exploiting a misconfigured server. It differs from vulnerability scanning, which typically identifies potential weaknesses but does not attempt to exploit them. Penetration testing concepts are fundamental to cybersecurity certifications like CompTIA Security+, CySA+, and CISSP.