Constructing the On/Off Covert Channel on Xen

Abstract

Virtualization technology is the basis of cloud computing. Multiple virtual machines on a single physical host are isolated from each other. However, covert channel breaks the isolation and leaks sensitive information covertly. In this paper, we construct one type of classic covert timing channel, the on/off channel, on the Xen hyper visor using shared memory. And then we evaluate its bit rate and transmission accuracy. The results show that this type of covert channel is a threat to virtualization technology.