  In this paper, we investigate denial-of-service attacks against status
updating. The target system is modeled by a Markov chain and an unreliable
wireless channel, and the performance of status updating in the target system
is measured based on two metrics: age of information and age of incorrect
information. Our objective is to devise optimal attack policies that strike a
balance between the deterioration of the system's performance and the
adversary's energy. We model the optimal problem as a Markov decision process
and prove rigorously that the optimal jamming policy is a threshold-based
policy under both metrics. In addition, we provide a low-complexity algorithm
to obtain the optimal threshold value of the jamming policy. Our numerical
results show that the networked system with the age-of-incorrect-information
metric is less sensitive to jamming attacks than with the age-of-information
metric. Index Terms-age of incorrect information, age of information,
cyber-physical systems, status updating, remote monitoring.
