What does a botnet refer to in cybersecurity?

A botnet refers to a collection of compromised computers that are controlled remotely by a malicious actor, often without the knowledge of the device owners. These compromised machines, known as "bots" or "zombies," are typically infected with malware that allows the operator to execute various types of attacks collectively. This could include Distributed Denial-of-Service (DDoS) attacks, sending spam emails, stealing data, or facilitating other cybercriminal activities. The ability to remotely control a network of such compromised devices maximizes the scale and impact of malicious actions, making the botnet a significant threat in cybersecurity.

The other options focus on different cybersecurity concepts but do not accurately describe a botnet. A server controlled by a malicious actor represents a single point of control rather than a network. A network of vulnerable computers points to security weaknesses rather than an organized collection under remote control. Lastly, malicious code infecting an industrial control system references a specific type of attack rather than the overarching concept of a botnet.