Mitigating HTTP GET FLOOD DDoS attack using an SDN controller

DDoS attacks are pre-dominant in traditional networks, they are used to bring down the services of important servers in the network, thereby affecting its performance. One such kind of attack is HTTP GET Flood DDoS attack in which a lot of HTTP GET request messages are sent to the victim web server, overwhelming its resources and bringing down its services to the legitimate clients. The solution to such attacks in traditional networks is usually implemented at the servers, but this consumes its resources which could otherwise be used to process genuine client requests. Software Defined Network (SDN) is a new network architecture that helps to deal with these attacks in a different way. In SDN the mitigation can be done using the controller without burdening the server. In this paper, we first show how an HTTP GET Flood DDoS attack can be performed on the webserver in an SDN environment and then propose a solution to mitigate the same with the help of the SDN controller. At the server, the attack is detected by checking the number of requests arriving to the web server for a certain period of time, if the number of request is greater than a particular threshold then the hosts generating such attacks will be blocked for the attack duration.