  A design-centric modeling approach was proposed to model the behaviour of the
physical processes controlled by Industrial Control Systems (ICS) and study the
cascading impact of data-oriented attacks. A threat model was used as input to
guide the construction of the CPS model where control components which are
within the adversary's intent and capabilities are extracted. The relevant
control components are subsequently modeled together with their control
dependencies and operational design specifications. The approach was
demonstrated and validated on a water treatment testbed. Attacks were simulated
on the testbed model where its resilience to attacks was evaluated using
proposed metrics such as Impact Ratio and Time-to-Critical-State. From the
analysis of the attacks, design strengths and weaknesses were identified and
design improvements were recommended to increase the testbed's resilience to
attacks.
