A botnet is a distributed network consisting of many compromised internet-connected devices, which are controlled by a centralized botmaster, and are utilized to perform synchronized tasks. Each infected machine is called a bot, and together their power is used to carry out various attacks. Botnets are usually created via malware infections, which gain persistence on the machines and “recruit” them to the botnet. Some of these malware variants can even self-propagate through networks, infecting many devices via one network entry point. The bandwidth amount “taken” from each bot is relatively small, so that the victim will not realize that their device is being exploited, but when thousands or even millions of machines are simultaneously instructed to perform a joint, targeted attack, the damage can be immense.
Although we are used to thinking of botnets as a collection of computers, these networks can be comprised of various types of devices – personal computers, laptops, mobile devices, smart watches, security cameras, and smart house appliances.