Which type of testing will most likely find zero-day vulnerabilities?

A.  Fuzz Testing

B.  White-Box Testing

C.  Black-Box Testing

D.  Stress Testing

Correct Answer: A

Explanation:

Fuzz Testing: As mentioned, fuzzing is designed to find unknown vulnerabilities by subjecting the software to a wide array of random and unexpected inputs. This makes it most likely to discover zero-day vulnerabilities.

White-Box Testing: While this approach can be thorough because it has full access to the source code, it often relies on the tester's knowledge of known vulnerabilities and best practices, making it less likely to find zero-day vulnerabilities compared to fuzz testing.

Black-Box Testing: This type of testing doesn't have access to the source code and tests the software from an external perspective. While it might find unknown vulnerabilities, it is generally less effective at finding zero-day vulnerabilities compared to fuzz testing.

Stress Testing: This is meant to evaluate how a system performs under extreme conditions, such as heavy load or low resources, rather than find vulnerabilities.