Distributed SYN Flood Attack

C.

A SYN flood attack is a type of denial-of-service (DoS) attack in which an attacker sends a large number of SYN packets (the first step in the TCP handshake) to a targeted server with the intention of overwhelming the server's resources and making it unavailable to legitimate users.

A distributed SYN flood attack is a more sophisticated version of this attack, in which multiple attackers coordinate their efforts to launch the attack from multiple sources, making it much harder to defend against.

Now, let's examine the given options and find the true statement about the distributed SYN flood attack:

A. A distributed SYN flood attack is carried out only by the valid address.

This statement is false. A distributed SYN flood attack can be carried out using both valid and spoofed IP addresses. Valid addresses are the IP addresses that are assigned to the attackers, while spoofed addresses are fake addresses that are used to mask the real source of the attack.

B. A distributed SYN flood attack is carried out only by spoofed addresses.

This statement is false. As mentioned above, a distributed SYN flood attack can be carried out using both valid and spoofed IP addresses.

C. Botnet could be used to launch a distributed SYN flood attack.

This statement is true. A botnet is a network of compromised computers that are controlled by an attacker. These computers can be used to launch a distributed SYN flood attack by sending SYN packets to the target server from multiple sources.

D. A distributed SYN flood attack does not completely deplete TCBs SYN-Received state backlog.

This statement is false. A distributed SYN flood attack can deplete a server's Transmission Control Block (TCB) backlog in the SYN-Received state, which can cause the server to become unresponsive to legitimate requests.

E. A distributed SYN flood attack is the most effective SYN flood attack because it targets server memory.

This statement is false. A distributed SYN flood attack does not target server memory directly. Instead, it overwhelms the server's resources by consuming all available TCBs in the SYN-Received state, which can cause the server to become unresponsive to legitimate requests.

Therefore, the correct answer is C. Botnet could be used to launch a distributed SYN flood attack.