In grey box penetration testing, the tester's knowledge is equivalent to what?

In grey box penetration testing, the tester's knowledge is typically equivalent to what an authorized user knows. This means that the tester has some limited access to the system, potentially including user credentials or documentation that provides insight into certain system functionalities or areas of interest. Grey box testing is a blend of black box testing, where the tester knows nothing about the system, and white box testing, where the tester has complete knowledge of the internal workings of the system.

The approach allows the tester to simulate the perspective of a legitimate user who understands some features of the system, thereby identifying vulnerabilities that a malicious insider or a legitimate user with ill intent might exploit. This technique is particularly effective in identifying security weaknesses that are not apparent from a purely external viewpoint, such as those arising from user permissions or application logic flaws.

This context helps highlight the value of understanding user-level access during penetration testing, which can lead to more comprehensive assessments of security posture in applications and systems.