What Is a Botnet?
A botnet is a network of devices, typically PCs but sometimes IoT devices, that have been infected with malware that enables a cybercriminal to remotely control them. This allows cybercriminals to use the combined computing power of the infected devices, or “bots,” to carry out various illicit activities including distributed denial of service (DDoS) attacks, data theft, phishing and spam campaigns, click fraud, and cryptomining.
Bot malware can also be used to snoop on user activity and steal login credentials, or “passwords.” Keylogging and packet sniffing are common tools for the collection of data from infected devices. A more advanced form of the attack uses proxy servers to obfuscate the traffic that bots send and receive, making it difficult for conventional cybersecurity measures like signature-based antivirus software to detect or intercept it.
Hackers can amass thousands or millions of infected computers, or zombie devices, to form a botnet. Then they control them via a command and control (C&C) server. The server is either centralized, in the client-server model, or it can be decentralized through the peer-to-peer (P2P) architecture.
Once a botnet is discovered, it can be disabled by shutting down the C&C servers or by removing the malicious code from infected devices. In some cases, the dismantling requires the support of law enforcement agencies. However, in recent years, attackers have evolved their botnet malware to evade detection and disruption. This includes using polymorphic code, domain generation algorithms, and encryption to obfuscate the botnet’s communication pathways.