Distributed Denial of Service (DDoS) remains a big concern in Cybersecurity. DDoS attacks are implemented to prevent legitimate users from getting access to services. The attackers make use of multiple hosts that have been compromised (i.e., Botnets) to organize a large-scale attack on targets. Developing an effective defensive mechanism against existing and potential DDoS attacks remains a strong desire in the cybersecurity research community. However, development of effective mechanisms or solutions require adequate evaluation of existing defense mechanism and a critical analysis of how these methods have been implemented in preventing, detecting, and responding to DDoS attacks.
This paper adopted a systematic review method to critically analyze the existing mechanisms. The review of existing literature helped classify the defense mechanism into four categories: source-based, core-router, victim-based, and distributed systems. A qualitative analysis was used to exhaustively evaluate these defense mechanisms and determine their respective effectiveness. The effectiveness of the defense mechanisms was evaluated on six key parameters: coverage, implementation, deployment, detection accuracy, response mechanism, and robustness. The comparative analysis reviewed the shortcomings and benefits of each mechanism.
The evaluation determined that victim-based defense mechanisms have a high detection accuracy but is associated with massive collateral as the detection happens when it is too late to protect the system. On the other hand, whereas stopping an attack from the source-end is ideal, detection accuracy at this point is too low as it is hard to differentiate legitimate and malicious traffic. The effectiveness of the core-based defense systems is not ideal because the routers do not have enough CPU cycles and memory to profile the traffic. Distributed defense mechanisms are effective as components can be spread out across the three locations in a way that takes advantage of each location.
The paper also established that the rate-limiting response mechanism is more effective than packet filtering method because it does not restrict legitimate traffic. The analysis revealed that there is no single defense mechanism that offers complete protection against DDoS attacks but concludes that the best defense mechanism is the use of distributed defense because it ensures that defense components are placed on all locations.
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