What is a Botnet?
A botnet is a network of malware-infected computers and other devices controlled by a malicious party known as a bot herder. Bot herders use botnets to execute cyberattacks like DDoS attacks, mass email spam attacks, click fraud campaigns, and many other types of criminal hacking. The motives for building a botnet vary, but they are mostly related to money or the desire to cause disruption.
The primary means by which threat actors gain control over a botnet is through remote access tools (RATs). RATs are rogue applications that allow the attacker to remotely control a victim’s system. These rogue applications can be installed on any computer in a botnet and are commonly used with other types of malware like keyloggers, spyware, Trojans, and ransomware.
Once a device is infected with botnet malware, it’s often difficult to regain control of the machine. This is because bots are designed to discover new devices and infect them rapidly. This can happen through a variety of mechanisms, such as exploiting zero-day vulnerabilities. The Mirai botnet, for example, was built through a series of exploits targeting vulnerable IoT devices, such as home routers and IP cameras.
To gain further control over a botnet, the bot herder will typically communicate with each infected machine via a command and control (C&C) server. C&C servers are centralized repositories that serve up new commands to the bots. However, more recent botnets have moved away from centralized models to decentralized peer-to-peer (P2P) approaches. This makes it more challenging for law enforcement and cybersecurity vendors to pinpoint and disrupt botnets.