Improving Hard Disk Contention-based Covert Channel in Cloud Computing Environment

Steganographic methods allow the covert exchange of secret data between parties aware of the procedure. The cloud computing environment is a new and emerging target for steganographers, but currently not many solutions have been proposed. This paper proposes CloudSteg, which is a steganographic method that creates a covert channel based on hard disk contention between the two cloud instances that reside on the same physical machine. Experimental results conducted using open-source cloud environment OpenStack show that CloudSteg is able to achieve a bandwidth of about 0.1 bps, which is 1000 times higher than is known from the state-of-the-art version.