Risk assessment of machinery system with respect to safety and cyber-security
Authors: Timo Malm, Toni Ahonen & Tero Välisalo
Download the report: Safety_and_security_assessmentReportSgn19.3.2018 (002).pdf
This report is related to the concern that a cyber-security risk could cause a safety risk and
furthermore an accident. There is already a tradition for how to treat safety risks related to
automated machinery, but cyber-security is quite new aspect. A cyber-security issue can
cause malfunction of a safety function or inherently safe design can be somehow bypassed.
When looking the risks in details, it can be seen that the cyber-security/safety risk of
automation is usually related to the safety integrity, availability or response time of the
safety-related control system. Furthermore, the cyber-security issue is usually related to
software and human access to the system.
The risk assessment processes for safety and cyber-security have similar phases, but the
point of view is different. The cause of an incident is from the safety point of view usually
failure, misuse or disturbance of a system whereas from the cyber-security point of view an
incident may originate from a threat and vulnerability and in most cases human is causing it.
We conclude that it would be difficult to benefit from a complete integration of safety and
cyber-security risk assessment processes into a single analysis, because there would be so
many aspects to consider and only few mutual effects. lt is recommended that the risks
assessments are compiled separately, however, any identified safety-critical cyber-security
issues should be added to the safety risk assessment process and associated risk treatment
be validated according to safety process. The conclusion related to functional safety and
cybersecurity can be mutual.