Abstract: With the continuous integration of informatization and industrialization,there are more and more intersecting parts between information domain and physical domain in industrial control systems,and network attacks on traditional information systems will threaten the industrial control system network.Traditional industrial control systems only consider the risks of functional safety,ignoring the impact of information security risks on functional safety.This paper proposes an integrated risk mode-ling method for functional safety and information security of industrial control system named SSPN-RA based on improved petri net,which includes three steps:integrated risk identification,integrated risk analysis and integrated risk assessment.This paper firstly identifies and abstracts the functional safety data and information safety data in the industrial control system,and then analyzes the collaborative attack path of functional safety and information security by constructing the petri net model combined with Kill Chain in the risk analysis process.Subsequently it quantifies the functional safety and information security nodes in the petri net,and finally calculates the risk value through the possibility of safety events and various losses caused by these safety events,so as to complete the integrated risk assessment of the industrial control system.In this paper,the feasibility of the proposed method is verified under the open-source simulation of chemical tank industrial control system,and compared with fault tree ana-lysis and attack tree analysis.Experimental results show that the proposed method can quantitatively obtain the risk value of industrial control system,and also solve the problem of cyber-physical collaborative attack and security risk that cannot be identified by the analysis of functional safety and information security.

Key words: Risk assessment, Petri net, Industrial control system, Security integrity, Functional safety, Information security