Which of the following best describes a passive attack?

• A. actively alters system resources
• B. stealthily intercepts communications
• C. blocks legitimate network traffic
• D. creates user impersonation

Answer: (B)

A passive attack is best described as one that involves stealthily intercepting communications without altering any data or systems. This type of attack is characterized by the attacker's goal of obtaining information without detection or active interference. By merely eavesdropping on communications, a passive attacker can gather sensitive data such as passwords, personal messages, or other confidential details without affecting the integrity or availability of the data or services involved.

This contrasts with other attack types, such as those that actively manipulate or block resources or impersonate users. For instance, actively altering system resources represents an active attack where the attacker changes system behavior, while blocking legitimate network traffic disrupts services. Creating user impersonation also indicates a level of interaction and deceit that goes beyond simply observing communications. Thus, passive attacks are primarily focused on surveillance and data gathering rather than interference or manipulation.