An assault on a network that floods it with so many additional requests that regular traffic is either slowed or completely interrupted. Unlike a virus or worm, which can cause severe damage to databases, a denial of service attack interrupts network service for some period. A distributed denial of service (DDOS) attack uses multiple computers throughout the network that it has previously infected. The computers act as "zombies" and work together to send out bogus messages, thereby increasing the amount of phony traffic. See smurf attack, SYN flood attack, land attack, teardrop attack and Ping of Death.