Covert channel detection techniques in cloud

This paper discusses covert channel attacks in VMM, with emphasis on some of its important detection techniques. This is an active research area whereby many security frameworks have been proposed for isolating VMs, but still covert channels in commercial clouds exist. Discussion in detail (with examples and expressions) has been done as to how information flow leads to covert channel and the methods used for covert channel detection. In this paper various scenarios are discussed where efforts have been made to detect all possible covert channels and counter the attacks. Among the basic four research areas in the study of covert channels (Define, Detect, Measure and Mitigate), Detection is the most challenging. This paper focuses on various detection techniques and tools available, and analyzes if those are sufficient to list all possible covert channels. A case study of Xen is discussed with respect to a storage covert channel.