What is it?
A network of computers that have been infected by a malicious software program -- a bot -- which turns them into zombie machines that can be remotely controlled by an attacker without the zombie machine owner’s knowledge.
Why is it important?
Cyber criminals use botnets, which can contain from 100 to over 100,000 zombies, as free resources to execute attacks. A botnet can execute Distributed Denial of Service (DDoS) attacks, store illegal content, and send spam, viruses, phishing email, and spyware.