Which of the following best describes a man-in-the-middle attack?

A man-in-the-middle attack is characterized by the interception of communication between two parties without their knowledge. In such an attack, the malicious actor secretly relays and possibly alters the communication between the two parties. This can lead to various security threats, including eavesdropping, data theft, or even impersonation.

The essence of this attack lies in its stealth and the way it exploits the trust between the communicating parties. By interposing themselves in the communication stream, the attacker can capture sensitive information or manipulate the messages sent between the individuals or systems involved.

Understanding this method is vital in network security, as it emphasizes the importance of encryption and secure communication protocols to protect against unauthorized access and data breaches. The other options, while involving different types of network threats, do not capture the specific nature of a man-in-the-middle attack. For instance, direct access to a server refers to unauthorized access, while overloading a network deals with denial-of-service attacks, and manipulating DNS records involves redirecting traffic rather than directly intercepting and altering communications.