What is an ACK Flood Attack?
An ACK flood attack is a type of Distributed Denial of Service (DDoS) attack where an attacker attempts to overload a server with a large number of TCP ACK packets. The primary objective of this attack is to disrupt regular traffic and deny service to legitimate users by overwhelming the target server.
ACK Flood Attack Mechanism
In a typical network communication, TCP ACK packets are used to acknowledge the receipt of data packets. However, in an ACK flood attack, these packets are sent in such high volumes that the server becomes inundated. Each ACK packet must be processed by the server, consuming a significant amount of computational resources. As the server attempts to manage and respond to this flood of packets, it experiences a severe strain on its processing capabilities. This strain can slow down the server’s performance, making it difficult or impossible to respond to legitimate user requests.
The effect of an ACK flood attack is similar to other types of DDoS attacks, where the ultimate goal is to make a service unavailable to its intended users. By monopolizing the server’s resources, the attacker ensures that the server cannot keep up with the demand from actual users. This can lead to slowdowns, disruptions, or complete crashes, rendering the service unusable during the attack period.
Protecting Against ACK Attacks
Defending against ACK flood attacks involves several strategies. Network administrators can implement rate limiting, which restricts the number of ACK packets accepted by the server within a specific timeframe. Additionally, advanced intrusion detection and prevention systems (IDPS) can identify and block suspicious traffic patterns indicative of an ACK flood. Robust firewall configurations and network traffic analysis also play critical roles in mitigating the impact of such attacks.
(Protection Principle: The DPDK FW will check the connection table for corresponding connection information, and if none is found, it will discard the packet.)
In summary, an ACK flood attack exploits the necessity for servers to process TCP ACK packets, overwhelming them with an unsustainable volume of traffic, and resulting in denial of service to legitimate users. Effective defense mechanisms are crucial to protect against these disruptive and potentially damaging cyberattacks. Learn more about CDNetworks Flood Shield(DDoS云清洗) to protect against ACK attacks.