Availability and Security Assessment of Smart Building Automation Systems: Combining of Attack Tree Analysis and Markov Models

The information and control system of smart building is considered as a set of subsystems including a building automation system (BAS). BAS security and availability during its life cycle are assessed using the Attack Tree Analysis (ATA) and Markov models. The ATA is applied to investigate any intrusions into the BAS by analyzing system probability of a fault/vulnerability to occur during period of time depending on failure probability of its subsystems. Markov model is used to calculate BAS availability considering the possibility of recovery and different kinds of the faults.