Anomaly based detection of DDoS attack using discrete transform and machine learning techniques

Distributed Denial of Service (DDoS) attacks is a serious threat to any online service on the internet. In contrast to other traditional threats, DDoS HTTP GET flood attack can exploit legitimate HTTP request mechanism to effectively deny any online service by flooding the victim with an overwhelming amount of unused network traffic. This paper introduces a new anomaly-based technique for discriminating between DDoS HTTP GET requests and legitimate requests using a combination of behavioural features. The main selected features are the diversity of the requested objects, requesting rates for all the requested objects, and request rate for the requested object with the most frequency. These parameters are selected as the proposed features that will be used together for effective discrimination within the proposed system.