Abstract
In this article, we present a proof theory for Attack Trees. Attack
Trees are a well established and useful model for the construction of
attacks on systems since they allow a stepwise exploration of high
level attacks in application scenarios. Using the expressiveness of
Higher Order Logic in Isabelle, we develop a generic
theory of Attack Trees with a state-based semantics based on Kripke
structures and CTL. The resulting framework
allows mechanically supported logic analysis of the meta-theory of the
proof calculus of Attack Trees and at the same time the developed
proof theory enables application to case studies. A central
correctness and completeness result proved in Isabelle establishes a
connection between the notion of Attack Tree validity and CTL. The
application is illustrated on the example of a healthcare IoT system
and GDPR compliance verification.