Certified Ethical Hacker (CEH) Practice Exam

White box testing is distinguished by the tester's complete knowledge of the system. This type of testing involves access to the internal structures and workings of the application, including source code, architecture, and configuration details. By having this comprehensive understanding, testers can design test cases that evaluate not just the system's functionality but also its internal pathways and security measures. This approach allows for a detailed exploration of the system's potential vulnerabilities, ensuring that all logical flows and pathways are well covered during testing.

In contrast, options that suggest partial knowledge, no knowledge, or external attack strategies do not align with white box testing. Partial knowledge would instead pertain more to grey box testing, while no knowledge is characteristic of black box testing. External attack strategies typically relate more to penetration testing scenarios where the tester mimics an external attacker who has no knowledge of the internal workings of the system. White box testing's strength lies in its comprehensive visibility, making it an invaluable approach for identifying systemic vulnerabilities and ensuring robust software security.