Constructing SDN Covert Timing Channels Between Hosts With Unprivileged Attackers

Software-defined networking (SDN) has been widely deployed due to its centralization and programmable features. However, these new features bring new threats at the same time. Previous studies have shown that SDN covert channels can be built with a privileged adversary that controls SDN key components, such as controller applications or SDN switches. In this paper, we propose new SDN covert timing channels between hosts without controlling applications, controllers, or having access to switches. Experiments in a real SDN testbed demonstrate the feasibility and effectiveness of our covert channels. To defend against the covert timing channels, we design a defense system named CovertGuard, which utilizes the timing characteristics of the covert channels’ delays to detect and eliminate covert channels effectively.