Hexagon received many malformed TCP/IP packets, causing their main server to crash. Which type of attack did the adversary use?

The scenario describes a situation where malformed TCP/IP packets are used to cause a main server to crash. This type of activity aligns with a Denial of Service (DoS) attack. A DoS attack typically involves overwhelming a server or network resource by flooding it with excessive traffic or exploiting vulnerabilities, which leads to service disruption. In this case, the use of malformed packets indicates an intention to exploit the server’s handling of network traffic, resulting in an inability to process legitimate requests, thereby rendering the service unavailable to users.

Other options represent different forms of attacks. Session Hijacking involves taking control of a user’s session after authentication, which is unrelated to packet manipulation or server crashing. A Man-in-the-Middle attack intercepts communication between two parties to eavesdrop or impersonate one of them, rather than directly causing server failures. Cross-Site Scripting (XSS) focuses on injecting malicious scripts into web pages viewed by users, which is also distinct from the actions described in the question. Therefore, the classification of this scenario as a DoS attack is clearly appropriate, reflecting the method of exploiting network protocols to achieve disruption.