Patent ID: 8646085

Claim:
An apparatus for reconfiguring a technical system based on analysis of security of said technical system, said apparatus comprising: an input for receiving technical information characterizing the technical system; a computer configured to perform the following acts: providing, based on the received technical information, a representation of potential attacks to the technical system in a directed graph of attack nodes having attributes related to the technical system, the directed graph associating each of a number of attack nodes with an indication whether a corresponding attack is reusable and weighting edges between the attack nodes, a weight of an edge between a reusable attack node and a successor attack node being representative of a number of times an attack of the reusable attack node is to be reused in order to reach the successor attack node; providing a ranking list that ranks sets of countermeasures to enable a selected set of countermeasures to be taken to improve security of the technical system, each set of countermeasures comprising at least one countermeasure, wherein providing the ranking list further comprises: logically applying each set of countermeasures to attacks in said directed graph; and determining a rank for each applied set of countermeasures based on effectiveness of the applied set of countermeasures with respect to reduction of risk of attacks; converting the directed graph into an attribute-dependent set of equation systems; to provide attribute values in said directed graph or in said attribute-dependent set of equation systems is configured to associate attribute values with each of a number of leaf nodes in the directed graph, to extract attribute values from at least one intermediate node and/or root node in said directed graph from the solved equation systems, and compute a rank based on the extracted attribute values; wherein a set of countermeasures is defined as a set of leaf nodes in the directed graph of attack nodes that the set of countermeasure counters, and the computer is configured to determine the rank of a set of countermeasures as a function of the attribute values of said at least one intermediate node and/or root node; a selector configured to select among the sets of countermeasures having highest rank; and a system reconfiguration unit configured to apply the selected set of countermeasures to the technical system.