What is a "botnet"?

A botnet refers to a network of compromised computers that have been infected with malware and are controlled by a hacker. This malicious control allows the hacker to use the devices to perform a variety of harmful activities without the owners’ knowledge. Botnets can be used for sending spam emails, launching distributed denial-of-service (DDoS) attacks, or even stealing sensitive information. They often consist of numerous devices, including personal computers, servers, and IoT devices, that have been infected and added to the hacker’s network.

In contrast, the other options describe different concepts. A secure connection between two devices pertains to encryption and secure communication, not a botnet. A software that encrypts data for security deals with protecting information from unauthorized access, rather than a network of compromised devices. A method for detecting vulnerabilities in a network relates to security assessment techniques, which also does not involve the control of a networked group of devices. These distinctions highlight the unique nature of a botnet in the realm of cybersecurity.