What is a Botnet and How Does it Operate?
A botnet is a network of compromised devices—including computers, mobile phones, and IoT hardware—under the control of one attacker (known as a botmaster or “bot-herder”). Malware infects each device, which then acts autonomously to execute commands sent by the bot master. The botnet’s distributed computing power enables cybercriminals to perform massive attacks that would be impossible for them to carry out alone.
Threat actors use botnets to distribute malware, steal data, and carry out other malicious activities, including conducting Distributed Denial-of-Service (DDoS) attacks. They can also infect devices to spy on users and sell stolen financial information—including credit card details—on the black market.
Botnets operate through a systematic lifecycle, starting with the recruitment phase. Attackers exploit vulnerabilities or social engineering tactics to gain initial access to computers, mobile phones, and IoT devices. Once compromised, the infected devices (also known as zombies) communicate with a central server that provides command and control (C&C).
Many early botnets operated using Internet Relay Chat (IRC) servers, allowing bot-herders to send commands remotely through pre-configured channels. More recently, attackers have shifted to peer-to-peer (P2P) bot programs that connect directly with each other and obfuscate communication through existing internet protocols.
The easiest way to detect and mitigate botnet activity is by detecting phishing attempts, blocking ports used for unauthorized communications, and limiting the types of software that can run on devices. Additionally, addressing security risks through the ingress and egress of network traffic (traffic entering and leaving your organization’s networks) can help prevent malware from reaching your devices.