What is a Botnet?
A botnet is a network of computers, Internet of Things (IoT) devices, smartphones, or other hardware that have been infected with malware and controlled by hackers. These bots can be used for malicious purposes such as distributing spam, disseminating inflammatory information while posing as human users, or attacking other networks on a large scale. Attackers also use bots to carry out cyberattacks such as distributed denial-of-service (DDoS) attacks, data theft, and cryptojacking for profit.
Bad bots can spread by stealing your device’s credentials, exploiting vulnerabilities in software, cracking weak authentication, or infecting you with Trojan horse malware that allows them to remotely access your devices. Once infected, bots then self-propagate by recruiting other devices within the same network to join the botnet. Bots then receive instructions from a central command-and-control (C2) server via covert channels, such as IRC servers, web domains, or HTTP, to perform tasks.
Bots can be built in a variety of ways and vary in size from just a few thousand to millions of devices. The most common method of creating a botnet is by spreading malicious software (malware) to as many devices as possible. This method allows attackers to gain autonomous growth capabilities, and the owners of the devices often are unaware that their devices have been compromised.
Security researchers and law enforcement attempt to disrupt botnet operations by blocking C2 channels, seizing bot infrastructure and domains, and removing malware. However, criminals quickly rebuild and adapt their infrastructure and bot variants to evade these efforts.