Botnet – Large groups of computers networked together that use their combined computing power to accomplish missions like solving complex mathematical problems or, more nefariously, to cause denial of service attacks. These groups are built from vulnerable systems with no concern for to whom they belong. Our work system, our home computer, or the MRI system at the hospital can become zombies on a botnet if they are not protected and monitored. Jason Andress and Steve Winterfield, Cyber Warfare: Techniques, Tactics, and Tools for Security Practitioners (2nd ed.) (2014).