TCP Based Denial-of-Service Attacks to Edge Network: Analysis and Detection

Abstract

Congestion control algorithms in TCP are designed for a co-operative environment with the assumption that the end hosts voluntarily participate in the congestion control process. The steady growth of malicious activities such as Denial-of-Service attacks (DoS) reveals that the Internet no longer remains as a network of only trusted entities. We focus on a special class of DoS attacks targeted to edge networks by exploiting the vulnerabilities of TCP congestion control to duplicate and optimistic acknowledgement spoofing. We analyse two DoS attack scenarios namely pulse and sustained attack arising from two different behaviours of the attacker. Our results show that such attacks are feasible and also reveal the negative impact of the attacks on the target. We present a method for detecting such attacks by passively monitoring the traffic of the targeted network. The detection is achieved by differentiating malicious streams of duplicate and optimistic acknowledgments from normal acknowledgments....