What is a Denial of Service (DoS) attack?

A Denial of Service (DoS) attack specifically aims to make a network, service, or system unavailable to users by overwhelming it with a flood of traffic or requests. The fundamental concept of a DoS attack lies in its ability to disrupt the normal functioning of a service, often rendering it inaccessible to legitimate users. This is typically accomplished by sending an excessive number of requests in a short period, consuming system resources such as bandwidth and processor power, which ultimately leads to downtime or failure of the system.

In contrast, other options describe different types of cybersecurity incidents or strategies. For instance, an attack that encrypts data to hold it for ransom pertains to ransomware, focusing on exploiting data rather than service availability. Securing data against unauthorized access describes protective measures rather than an attack form, while tactics aimed at stealing personal information relate to phishing or data breaches, which are also distinct from the disruption caused by a denial of service attack.