A Security Model of SCADA System Based on Attack Tree

Abstract

In recent years, attacks against SCADA systems have emerged in endlessly. Therefore, it is of great significance to study the security issues of SCADA systems. Although many scholars have studied the security of SCADA systems, their research tends to focus on one aspect of security analysis or security protection design, lacking the organic combination of the two. Therefore, this paper proposes a security model of SCADA system based on attack tree—BPATSM, which contains two modules: security analysis model and security protection scheme. For the security analysis of SCADA systems, there are a lot of methods. Attack trees are a common method for security analysis. However, the traditional attack tree model can only analyze the structure of the attack, but cannot analyze the characteristics of the attack, nor it can analyze the bias of the attack that has occurred and predicted the possibility of the attack that will occurred, so its analysis efficiency is not high. Therefore, this paper proposes a preference attack tree (PAT) model based on the attack tree model, that is, adding the attributes of the number of attacks on the nodes of the attack tree to represent the preference, which can improve the efficiency of attack tree model analysis. Based on PAT analysis, this paper also proposes a security protection scheme for SCADA system, which can switch three levels of security protection according to different protect requirements. Finally, the BPATSM model is implemented in a semi-simulation system and tested its security.