Botnet A botnet is a group of bots, connected through the Internet, with the ability to be controlled by a malicious individual or group. A bot computer is typically infected by visiting a website, opening an email attachment, or opening an infected media file. A botnet can have tens of thousands, or even hundreds of thousands of bots. These bots can be activated to distribute malware, launch DDoS attacks, distribute spam email, or execute brute force password attacks. Botnets are typically controlled through a command and control server. Cyber criminals will often rent out Botnets, for a fee, to third parties for nefarious purposes. The figure shows how a botnet traffic filter is used to inform the worldwide security community of botnet locations.