为评估复杂信息系统安全风险,该文提出了一种基于资产间威胁传播的风险评估方法。该方法将复杂信息系统各资产间的威胁传播路径定义为一棵威胁传播树,通过计算威胁传播树中各结点的期望损失以及威胁传播树出现的概率来对整个复杂信息系统进行风险安全评估。为验证本文所提方法的正确性、可行性,该文选取了一个具有代表性的实例阐述了所提方法在复杂信息系统安全风险评估中的应用。通过实例分析表明基于威胁传播的复杂信息系统安全风险评估方法强调不同结点受到威胁作用概率的不同性,威胁在结点之间的传播性,并且能够提示在不同时间段的重点保护结点。比起传统的孤立结点分析方法更具客观性与准确性,能够很好地指导安全风险管理者为复杂信息系统制定合理的安全保护策略。

This paper presents a risk assessment method based on threat propagation between assets for assessing the risks related to complex information system security. This method describes the threat propagation route between assets as a threat propagation tree, with the risk to the complex information system security assessed by the expected value loss of each node in the threat propagation tree with the probability of each step in the threat propagation tree. The accuracy of this model is evaluated by applying the model to a representative complex information system. The analysis shows that this method represents the different probabilities for different threatened nodes and the threat propagation between nodes to identiby the key protected nodes during different periods. The system is more objective and accurate than the traditional isolated node analysis method and is able to guide security risk managers to formulate reasonable security protection strategies for complex information systems.