Denial-of-Service Attack

A denial-of-service attack is the offense of deliberately overwhelming a computer system, network or online service with traffic or requests so that it becomes slow, unstable or entirely unavailable to its legitimate users, an offense against the availability of a computer system rather than against the confidentiality of the data it holds, which is what distinguishes it from computer hacking aimed at unauthorized access. Most modern attacks of this kind are carried out as a distributed denial-of-service attack, in which the offender directs traffic from a very large number of separate compromised devices, often recruited through malware distribution into what is commonly called a botnet, at a single target simultaneously, making the attack far harder to block than traffic from a single source and correspondingly more damaging to the target. Motives for denial-of-service offenses vary widely and are treated as aggravating or contextual factors rather than separate offenses, ranging from financial extortion, in which the attacker demands payment to stop the disruption, to ideological protest against the target organization, to attacks carried out as one tactic within a broader campaign of cyber espionage between states or organized groups. Because the offense can disable critical online infrastructure, including services relied on for banking, communication or public safety, most legal systems treat a denial-of-service attack against such infrastructure as a substantially aggravated form of the offense.