What best describes a Distributed Denial of Service (DDoS) attack?

A Distributed Denial of Service (DDoS) attack is characterized by its method of overwhelming a particular target, usually a server or website, with an excessive volume of traffic. This is achieved by utilizing multiple compromised systems or devices to flood the target with numerous requests. The goal is to exhaust the target’s resources, making it unable to respond to legitimate requests and effectively shutting down its operations, which results in a denial of service to legitimate users.

This answer accurately captures the essence of a DDoS attack, focusing on how the attack is orchestrated through distributed means. In a DDoS, the multiple systems that send requests are typically part of a botnet—a collection of internet-connected devices that have been infected and can be controlled remotely.

The other choices do not align with the definition of a DDoS attack. For instance, one option describes unauthorized access to foreign systems, which involves penetration rather than overwhelming traffic. Another implies network engineers are tracking illegal access, which does not relate to the disruptive intent of a DDoS attack. Lastly, while the harassment or extortion of ISP customers is a malicious act, it does not capture the technical mechanics behind how a DDoS attack operates.