Evaluating the mitigating effect on HTTP lood attacks using an application laye Challenge-response approach

DDoS attacks are a major threat to internet services today. These attacks can affect millions of users and result in great financial pain. HTTP floods are a subset of DDoS attacks with the purpose of hindering users accessing the attacked resource. It is challenging to combat HTTP flood attacks as they operate in the application layer and passes through firewalls like legitimate traffic does. This thesis investigates an application layer mitigation system using the challenge-response authentication protocol. The purpose of this system is to achieve high portability that can mitigate HTTP floods for any application in the application layer. The results of the experiments show that the system can successfully mitigate HTTP floods when malicious HTTP requests are ignored. The system introduces a high overhead cost due to requirement of additional requests for file retrieval