Which type of attack involves overwhelming a system with traffic to disrupt its operations?

A Denial of Service (DoS) attack is characterized by overwhelming a system, service, or network with excessive traffic or requests, aiming to exhaust resources and render the service unavailable to legitimate users. This kind of attack can disrupt normal operations and often leads to downtime, which can be detrimental to businesses that rely on their online presence and digital services.

During a DoS attack, the system struggles to respond to legitimate requests due to the barrage of malicious traffic, effectively denying service to genuine users. This type of attack can take various forms, including flooding the target with traffic or sending requests that consume resources, thus causing slowdowns or crashes.

The other types of attacks mentioned are fundamentally different in nature. Phishing targets individuals to acquire sensitive information fraudulently, while a Man-in-the-Middle attack intercepts communication between two parties to eavesdrop or inject malicious content. An SQL injection attack manipulates an application's database queries to access or manipulate information without proper authorization. Each of these has distinct tactics and objectives that do not involve the overwhelming of a system with traffic.