Abstraction-based analysis of known and unknown vulnerabilities of critical information infrastructures

The systematic protection of critical information infrastructures requires an analytical process to identify the critical components and their interplay, to determine the threats and vulnerabilities, to assess the risks and to prioritise countermeasures where risk is unacceptable. The abstraction-based approach presented here builds on a model-based construction of an attack graph with constraints given by the network security policy. A unique feature of the presented approach is, that abstract representations of these graphs can be computed that allow comparison of focused views on the behaviour of the system. In order to analyse resilience of critical information infrastructures against exploits of unknown vulnerabilities, generic vulnerabilities for each installed product and affected service are added to the model. The reachability analysis now considers every possible choice of product, and so all alternatives are evaluated in the attack graph. The impact of changes to security policies or network structure can be visualised by differences in the attack graphs. Results of this analysis support the process of dependable configuration of critical information infrastructures.