What type of attack aims to overload a network and disrupt service availability?

A Denial of Service (DoS) attack specifically targets the availability of a network or service by overwhelming it with excessive traffic. The primary goal of this type of attack is to render the affected resources unavailable to legitimate users by consuming all their bandwidth or server resources. This is achieved by flooding the target system with requests, leading to slow performance or complete downtime.

In contrast, hacking attempts can involve various tactics aimed at gaining unauthorized access to systems but do not inherently focus on availability disruption. Malware infiltration refers to the introduction of malicious software into a system with the intent to cause damage or steal data, rather than directly overloading resources. Phishing attacks are designed to deceive users into divulging sensitive information, primarily targeting credentials and personal data rather than directly affecting network performance. Therefore, the emphasis on overwhelming the network service specifically identifies the Denial of Service attack as the most accurate answer.