How to Detect a Botnet
A botnet is a network of computers, smartphones, and Internet of Things (IoT) devices that have been infected with malware that allows a hacker to remotely control them. Each infected device, referred to as a “bot,” silently connects to the attacker’s command and control server, or C2, for instructions.
Based on the commands received, bots execute malicious activities. Examples include launching distributed denial of service (DDoS) attacks by flooding target servers with massive traffic to disrupt services or websites, sending spam emails in bulk, and stealing online credentials through form grabbing and keystroke logging. Bots may also generate fake clicks on ads to earn money or deliver ransomware and spyware to infect additional devices.
The attacker that controls the botnet is known as the bot herder. The herder distributes the botnet-infected malware through phishing emails, drive-by downloads on compromised websites, or software vulnerabilities exploited by Trojan horse programs that appear legitimate but contain malicious code. A bot herder can grow a botnet by infecting more devices through these channels and by deploying new malware variants to existing infections.
Detecting botnets can be challenging, but knowing what to look for helps. Frequent system crashes, slow application responsiveness, and unexplained data usage are signs that malware on your computer or IoT device is working overtime for a bot herder. You should also pay attention to how hot your device is even when it’s not being used; tasks such as cryptocurrency mining or spam delivery can strain the processor and battery, causing overheating. Disabling a botnet’s C2 servers can cut off the head of the attack, but eliminating infection is the best way to stop threats from spreading in the first place.