Denial of service

Denial of service (DoS) is a malware routine that interrupts or inhibits the normal flow of data into and out of a system. Most DoS attacks consume system resources, such that, in a short period of time, the target is rendered useless. A form of DoS attack is when a Web service (like a Web site or a download location) is accessed massively and repeatedly from different locations, preventing other systems from accessing the service and retrieving data from it. When a DoS attack is launched from different locations in coordinated fashion, it is often referred to as a distributed denial of service attack (DDoS).