Which principle ensures the system only provides access to essential capabilities?

Which principle ensures the system only provides access to essential capabilities?

• A. Least Functionality
• B. EAL
• C. Trusted OS
• D. BIOS

Answer: (A)

The principle being tested is that a system should provide only the features and capabilities that are necessary to perform its legitimate tasks. This approach limits what the system exposes, reducing the attack surface and opportunities for misuse or exploitation. In practice, it means disabling or removing unused services, protocols, and software, and granting only the minimal set of permissions required for each function or user. By keeping the feature set tight, you make it harder for attackers to find a weakness to exploit and you simplify security management.

This idea is distinct from a few other security concepts. For example, a rating like EAL measures the level of assurance or confidence in how well a product is designed and tested, not how many features it exposes. A trusted OS refers to an operating system built with strong security properties, but it doesn’t automatically enforce limiting functionality to the minimum needed. BIOS relates to firmware that initializes hardware at boot and isn’t about restricting features or capabilities in the running system.