A penetration test, informally pen test, is an attack on a computer system that looks for security weaknesses, potentially gaining access to the computer's features and data.[1][2]

The process typically identifies the target systems and a particular goal—then reviews available information and undertakes various means to attain the goal. A penetration test target may be a white box (which provides background and system information) or black box (which provides only basic or no information except the company name). A penetration test can help determine whether a system is vulnerable to attack, if the defenses were sufficient, and which defenses (if any) the test defeated.[3]

Security issues that the penetration test uncovers should be reported to the system owner.[4] Penetration test reports may also assess potential impacts to the organization and suggest countermeasures to reduce risk