What is a botnet?

A botnet is accurately defined as a network of infected computers controlled by an attacker. In this context, the term "botnet" refers to a group of computers that have been compromised by malware and can be remotely controlled to carry out various malicious activities without the knowledge of the device owners. These activities may include launching distributed denial-of-service attacks (DDoS), sending spam emails, or stealing sensitive data.

The effectiveness of a botnet lies in its ability to leverage many compromised devices (often referred to as "zombies") to amplify the scale and impact of cyberattacks. It is important to recognize that the computers within a botnet can belong to any user worldwide, making it difficult to trace the origin of these attacks. This understanding distinguishes the nature and implications of a botnet from other options presented, which either describe legitimacy or protective measures rather than the malicious intent behind a botnet.