Denial-of-Service (DoS) attacks clog a network with real or fictitious requests to the point that normal operations stop. A DoS attack can also work by deleting or corrupting information that the system expects to be there. A DoS attack does not require that the attacker have prior access to the targeted machine. All that is required is the opportunity for simple and anonymous access.

The goal of a DoS attack is to overwhelm a target computer and there are an endless variety of DoS attacks designed to do that. New exploits are constantly publicized to other attackers, who write them into scripts for attacks of their own.

DoS attacks can consume resources including bandwidth, processors, and disk space and even max out their usage so the device or system cannot do anything else and possibly crash. They can trigger errors and disrupt components, information, or configuration. They can also interfere with devices communicating with one another.