an authorized attempt to breach a system using attacker techniques

The process of using approved, qualified personnel to conduct real-world attacks against a system so as to identify and correct security weaknesses before they are discovered and exploited by others.

A system test, often part of system certification, in which evaluators attempt to circumvent the security features of the system and penetrate various layers of systems resources.

The portion of security testing in which the evaluators attempt to circumvent the security features of a system. The evaluators may be assumed to use all system design and implementation documentation, which may include listings of system source code, manuals, and circuit diagrams. The evaluators work under the same constraints applied to ordinary users. A penetration test is similar in scope to a vulnerability assessment but is usually more aggressive in its efforts to simulate an attack

A penetration test is a method of evaluating the security of a computer system or network by simulating an attack by a hacker. The process involves an active analysis of the system for any weaknesses, technical flaws or vulnerabilities. This analysis is carried out from the position of a potential attacker, and can involve active exploitation of security vulnerabilities.