A network layer covert channel in ad-hoc wireless networks

Covert channels violate both secrecy and integrity properties of trusted systems. This paper investigates ad-hoc wireless networks´ susceptibility to covert channels through manipulating the routing protocol operations. Although the basic idea applies to the whole class of reactive routing protocols, we concentrate on the ad-hoc on-demand distance vector (AODV) protocol. We demonstrate four candidate multi-hop covert channels and provide detailed analysis on the most promising one which uses the destination ID information carried by the routing control packets. Simulation results show that performance of the covert channel depends on various network characteristics. Counter measures against the covert channel should also adapt to the network changes to take full effect.