Automated generation of attack trees with optimal shape and labelling

Abstract: This article addresses the problem of automatically generating attack trees that soundly and clearly describe the ways the system can be attacked. Soundness means that the attacks displayed by the attack tree are indeed attacks in the system; clarity means that the tree is efficient in communicating the attack scenario. To pursue clarity, we introduce an attack-tree generation algorithm that minimises the tree size and the information length of its labels without sacrificing correctness. We achieve this by i) introducing a system model that allows to reason about attacks and goals in an efficient manner, and ii) by establishing a connection between the problem of factorising algebraic expressions and the problem of minimising the tree size. To the best of our knowledge, we introduce the first attack-tree generation framework that optimises the labelling and shape of the generated trees, while guaranteeing their soundness with respect to a system specification.