What is a Botnet?
A botnet is a network of compromised computers, servers, and Internet of Things devices (IoT) that are weaponized to conduct large-scale cyber attacks, steal vast amounts of data, and disrupt business operations. Cybercriminals can leverage these networks to cripple websites, inflict massive DDoS attacks, distribute spam, and harvest sensitive corporate credentials.
The hacker that controls the network, known as a botmaster or bot herder, uses command and control servers to send instructions to infected devices, or bots. These servers communicate with the bots by sending updates that the bots use to perform tasks like launching DDoS attacks, sending spam, or performing other malicious activities.
Once the bots receive commands from the C&C servers, they launch their intended attacks. These can include DDoS attacks in which the botnet floods a target server or network with traffic to overwhelm resources and render it unusable, spam attacks in which the botnet sends spam emails to targets, or malware attacks in which the botnet installs ransomware, cryptojacking, and other malicious software on the target device.
Cyber criminals can build botnets on their own or rent them from the dark web. Botnets can attack any operating system, including desktop and mobile computers as well as IoT devices. The most popular malware, such as Zeus, Emotet, and Mirai, are built on top of botnets. These malware programs gain initial access to targeted endpoints via phishing, unpatched vulnerabilities, or weak IoT credentials. Once they have gained access, the malware sends a call home or beacon to a central server to register and establish its connection to a botnet.