What type of attack involves flooding a system with excessive requests?

A Denial-of-Service (DoS) attack is characterized by overwhelming a system with excessive requests, aiming to exhaust its resources and make it unavailable to legitimate users. This attack works by using various techniques to send more traffic than a server can handle, thus causing performance degradation or total shutdown. It exploits the limits of a system's bandwidth, processing power, or memory, ultimately denying access to genuine users.

In contrast, a phishing attack primarily focuses on tricking individuals into revealing sensitive information, usually leveraging social engineering techniques. A man-in-the-middle attack involves intercepting communication between two parties to eavesdrop or manipulate the exchange. SQL injection attacks exploit vulnerabilities in an application's database layer to execute malicious SQL code, allowing unauthorized access to data without involving excessive traffic or requests to the system directly.