CyberGlossary

Malware

Zombie Computer

Also known as: Bot, Drone

Definition

An internet-connected device secretly compromised by malware so an attacker can remotely command it, typically as part of a botnet.

A zombie computer is a host that has been infected with malicious code allowing a remote operator to issue commands without the owner's knowledge. Once enrolled, the device receives instructions from a command-and-control (C2) channel and can be used to send spam, mine cryptocurrency, host phishing kits, launch DDoS attacks, or pivot deeper into networks. Zombies are typically created through phishing, drive-by downloads, exposed services, or weak credentials, and they may stay dormant for long periods to evade detection. Defences include endpoint protection, prompt patching, egress filtering, DNS monitoring for C2 domains, and isolating or reimaging infected systems.

Examples

  • A home router conscripted into the Mirai botnet to flood a target with traffic.
  • An office workstation quietly relaying spam after a malicious macro executed.

Related terms