Quantitative security and safety analysis with attack-fault trees

TitleQuantitative security and safety analysis with attack-fault trees
Publication TypeConference Paper
Year of Publication2017
AuthorsKumar R., Stoelinga M.IA
Conference NameProceeding of the 18th IEEE International Symposium on High Assurance Systems Engineering, Singapore
Date PublishedJanuary
PublisherIEEE Computer Society
Conference LocationUSA
KeywordsMulti parameter attack trees, Quantitative analysis, Safety and security modelling, Stochastic model checking

Cyber physical systems, like power plants, medical devices and data centers have to meet high standards, both in terms of safety (i.e. absence of unintentional failures) and security (i.e. no disruptions due to malicious attacks). This paper presents attack fault trees (AFTs), a formalism that marries fault trees (safety) and attack trees (security). We equip AFTs with stochastic model checking techniques, enabling a rich plethora of qualitative and quantitative analyses. Qualitative metrics pinpoint to root causes of the system failure, while quantitative metrics concern the likelihood, cost, and impact of a disruption. Examples are: (1) the most likely attack path; (2) the most costly system failure; (3) the expected impact of an attack. Each of these metrics can be constrained, i.e., we can provide the most likely disruption within time t and/or budget B. Finally, we can use sensitivity analysis to find the attack step that has the most influence on a given metric. We demonstrate our approach through three realistic cases studies.