Special considerations for doing risk assessment of industrial control systems

Abstract

This paper provides special considerations that organizations have to pay attention for while doing risk assessment. The culture of safety and safety assessments is well established within the majority of the Industrial Control Systems (ICS) user community. Information security risk assessments should be seen as complementary to such assessments though the assessments may use different approaches and cover different areas. Safety assessments are concerned primarily with the physical world. Information security risk assessments primarily look at the digital world. However, in an ICS environment, the physical and the digital are intertwined and significant overlap may occur. It is important that organizations consider all aspects of risk management for safety (e.g., risk framing, risk tolerances), as well as the safety assessment results, when carrying out risk assessments for information security. The personnel responsible for the information security risk assessment must be able to identify and communicate identified risks that could have safety implications. Conversely, the personnel charged with safety assessments must be familiar with the potential physical impacts and their likelihood developed by the information security risk assessment process. This paper describes potentional physical impacts of an ISC incident, shows impact, physical disruption of an ICS process can made. It demonstrates importancy of incorporating non-digital aspects of ICS into impact evaluations, provides main categories of non-digital ICS control component and shows basic considerations when considering the possible mitigation effects of non-digital control mechanisms. Also, this paper considering the propagation of impact to connected systems.