Quantitative Cyber Risk Reduction Estimation Methodology for a Small Scada Control System.

Flynn, M. A. ; Beitel, G. A. ; Boyer, W. F. ; McQueen, M. A.

Technical Information Center Oak Ridge Tennessee

关键词: Computerized control systems;    Remedial action;    Security;    Risk;    Attack;   

RP-ID  :  DE2008911188

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We propose a new methodology for obtaining a quick quantitative measurement of the risk reduction achieved when a control system is modified with the intent to improve cyber security defense against external attackers. The proposed methodology employs a directed graph called a compromise graph, where the nodes represent stages of a potential attack and the edges represent the expected time-to-compromise for differing attacker skill levels. Time-to-compromise is modeled as a function of known vulnerabilities and attacker skill level. The methodology was used to calculate risk reduction estimates for a specific SCADA system and for a specific set of control system security remedial actions. Despite an 86% reduction in the total number of vulnerabilities, the estimated time-to-compromise was increased only by about 3 to 30% depending on target and attacker skill level.