What is a Botnet?
A botnet is a collection of internet-connected devices, such as PCs, servers, mobile phones and IoT (Internet of Things) devices, infected by malware and under the control of cybercriminals. The malware infects the devices and turns them into remote-controlled “bots,” or zombies, that work together for illicit purposes without the device owners’ knowledge. The bots are often used to send spam emails, engage in click fraud and generate malicious traffic for distributed denial of service attacks (DDoS). Cyber criminals also offer botnets for rent on the black market.
Typically, the malware infects the devices by exploiting software vulnerabilities or using drive-by downloads on compromised websites. Once a device joins a botnet, it communicates with a command-and-control (C&C) server through covert communication channels like Internet Relay Chat (IRC), email or even a peer-to-peer network. The bot herder updates the malware and evades detection by continuously searching for new ways to connect to infected systems or to other C&C servers.
If you think your computer might be part of a botnet, look for signs such as slow reboots and shutdowns, applications that randomly crash or a suspiciously high amount of memory usage. Also keep an eye out for a sudden increase in your energy bills due to the CPU processing power that is being used for botnet tasks such as cryptojacking.