What does a Denial of Service (DoS) attack aim to achieve?

A Denial of Service (DoS) attack is specifically designed to disrupt the normal functioning of a targeted server, service, or network, effectively making it unavailable to users. The primary objective of such an attack is to overwhelm the target with a flood of traffic or requests, which can lead to degraded performance or complete shutdown. By achieving this disruption, the attacker can deny legitimate users access to essential services, creating a significant impact on operations, reputations, and sometimes causing financial losses to businesses.

The other options focus on objectives that do not align with the goals of a DoS attack. Improving system performance is contrary to the nature of a DoS attack, which aims to create bottlenecks. Encrypting data for ransom pertains to ransomware attacks, where the threat is to hold data hostage rather than disrupt access. Discovering system vulnerabilities relates to penetration testing or ethical hacking, where the goal is to identify security weaknesses, not to disrupt services. Thus, the correct understanding of a DoS attack centers on its aim to disrupt service availability.