Also known as DDoS.

Distributed Denial of Service is a hack which overwhelms the target (often a high-profile website) through a coordinated swarm of ‘requests for service’ or ‘hits’, orchestrated through a network of compromised or ‘zombie’ computers. Hackers using this attack interrupt the services provided by the targeted website by swarming it with spurious connection requests. The purpose is usually disruption for political or other purposes, or for monetary gain: a DDOS attack is often followed by a request for a ransom. It is described as ‘Distributed’ because the attack originates from multiple sources, with the hacker having infiltrated multiple computers in the creation of a network under their control.