We exploit Decision Networks (DN) for the analysis of attack/defense scenarios. DN extend both the modeling and the analysis capabilities of formalisms based on Attack Trees, which are the main reference model in such a context. In particular, DN can naturally address uncertainty at every level, including the interaction level of attacks and countermeasures, making possible the modeling of situations which are not limited to Boolean combinations of events. Furthermore, inference algorithms can be exploited for a probabilistic analysis with the goal of assessing the risk and the importance of the attacks (with respect to specific sets of countermeasures), and selecting the optimal set (with respect to a specific objective function) of counte...