Due to the openness of operation systems and communication interfaces, an increasing number of cyber attacks can easily sneak into Cyber-Physical Systems (CPSs) and cause very serious consequences. Denial-of-service (DoS) attack is one particularly common type of cyber attacks in CPSs. A great deal of efforts have been expended in investigating the effect of power-constrained DoS attacks on the performances of CPSs. Almost all of them assume that communication channel states are unaltered. However, more practically, the variation of communication channel states will impact the consequence of DoS attacks, and thus this factor should not be ignored when investigating the security issues of CPSs. In this talk, we consider the scenario that the sensor data are transmitted through a standard block fading communication channel. From the viewpoint of the DoS attacker, we construct optimization problems considering jointly the system performance indexes and the attack power consumption. Then we transform the original problem into a Markov decision problem and show the existence of optimal solution. As it is difficult to provide an analytical expression of optimal attack strategy, the objective function is approximated to derive an analytical expression of the suboptimal attack strategy.
