What is a Botnet?
A Botnet is a network of computers, Internet of Things (IoT) devices, or smartphones that have been infected with malware and controlled by a hacker. The compromised devices are also called Zombies or Bots and are part of an army that the hacker uses for various purposes like launching DDoS attacks, harvesting credentials, or executing CPU-intensive tasks. Botnet malware infects a device through various channels such as drive-by downloads, malicious email attachments, and exploiting software vulnerabilities. Once infected, a bot remains dormant until an attacker commands it to take action. Hackers typically establish a central server to control all the bots, known as a command-and-control (C&C) center. However, attackers can also use a peer-to-peer (P2P) model where every infected device functions as the C&C. These systems are harder to shut down, so they’re more popular among cyber criminals.
Initially, bots were created to make time-consuming tasks easier. For example, they were used to proctor chatrooms and eject users who violated the room’s policy. But, over time, criminals found new ways to use bots for their own purposes. The Mirai botnet, for instance, enables hackers to flood targets with traffic to cause DDoS attacks and other damages. Hackers can even lease a botnet on several Internet forums and use it to perform DDoS assaults without exposing their identity.
You can detect the presence of a botnet by observing a sudden spike in your bandwidth consumption or a dip in your Internet speed. Additionally, you might notice that system files have been changed or modified without your permission. To mitigate the risk, ensure your firewall is configured with proper ingress and egress filters that block communication channels used by bots to connect to C&C servers.