Which of the following best describes a botnet?

A botnet is accurately characterized as a network of infected devices that are controlled by a single entity, often referred to as a "botmaster." These infected devices, or "bots," can include computers, servers, IoT devices, and more. Once compromised, these devices can be remotely commanded to execute various types of attacks, such as Distributed Denial of Service (DDoS) attacks, spamming, or spreading malware. The core functionality of a botnet hinges on its ability to leverage the resources of numerous infected machines to achieve malicious objectives, thus making it a significant threat in the realm of cybersecurity.

The other options do not accurately reflect the nature of a botnet. A group of cybersecurity professionals describes skilled individuals who protect systems, which is distinct from the malicious and automated nature of a botnet. A tool for securing data suggests a legitimate application aimed at enhancing security, whereas botnets exploit vulnerabilities. Lastly, a method for sharing files securely is unrelated to the inherent purpose of a botnet, which revolves around malicious activity rather than fostering secure communications.