What attack strategy is used during a distributed denial of service (DDoS) attack that makes services inaccessible for legitimate users?

The chosen answer, service disruption, accurately identifies the strategy employed during a distributed denial of service (DDoS) attack. In a DDoS attack, multiple compromised systems are used to flood a targeted server, service, or network with an overwhelming amount of traffic. This traffic overload renders the targeted resources unable to respond to legitimate user requests, effectively making the services inaccessible. The goal of the attacker is to disrupt normal service operations, leading to downtime or degraded performance for legitimate users.

In contrast, the other choices refer to different attack strategies that do not specifically target service availability in this manner. A data breach involves unauthorized access to sensitive data, typically for espionage or theft, rather than disrupting service. A phishing attack is designed to deceive individuals into providing personal information or credentials, rather than causing system downtime. Lastly, a man-in-the-middle attack involves interception and potential manipulation of communications between two parties, focusing more on data interception than service disruption. Thus, service disruption is indeed the correct term to describe the strategy utilized in a DDoS attack.