Detecting denial of service by modelling web-server behaviour

Abstract

The article presented here discusses a system which characterizes HTTP traffic and discriminates between legitimate and other kinds of HTTP traffic, such as those generated by Botnets or distributed denial of service (DDoS) tools. The system presented in this paper uses three analyses that are sequentially applied to the traffic flow to detect abnormal users. Combining statistical methods as well as analysis of HTTP request paths and the access time to the different resources in the web server, we have labelled abnormal users in real traffic flow. First, we have tested our prototype in real traffic from a multi-site web server detecting all abnormal users, such as an illegitimate audit of the server, Google bot and web-crawlers. In: a second experiment, the most common DDoS attacks were introduced in the real traffic flow. As a result, all suspicious users were detected and labelled. © 2013 Elsevier Ltd. All rights reserved.