Khan Academy The Internet Practice Test

Which statement best defines a distributed denial-of-service attack?

It uses a small number of devices to slowly drain a server's resources.

It targets a single user with phishing messages.

It compromises data confidentiality on a server.

It uses many devices to flood a target with traffic and disrupt service.

A distributed denial-of-service attack centers on overwhelming a target with traffic from many sources. By using a large number of compromised devices, the attacker floods the target, exhausting its bandwidth or processing power and making the service unavailable to legitimate users. That’s why the statement describing using many devices to flood a target with traffic and disrupt service is the correct definition. The other scenarios describe different security issues: a DoS with only a few devices isn’t distributed, phishing targets people, and compromising data confidentiality concerns data breaches rather than service disruption.