  Internet of Things (IoT) systems are recently being employed in various types
of critical infrastructure, including integrated rescue systems, healthcare,
defence, energy and other fields. Recently, the security and safety of IoT
systems, in general, has been questioned by a number of studies. Raised
concerns do not relate to the IoT technology in principle but to poor
engineering practices that are mostly preventable. In critical infrastructure,
demand for safety and security is strongly present and justifies a discussion
about the general resilience of IoT systems. In this context, resilience
includes system resistance to cyberattacks and its stability to operating
conditions and system reliability and safety in terms of present flaws. In this
paper, we discuss relevant factors impacting the resilience of IoT systems in
the critical infrastructure and suggest possible countermeasures and actions
mitigate the potential effects of these factors. Contrary to the previous work,
an unique critical system Model-based Testing viewpoint is taken in this
analysis.
