  Critical Infrastructure Protection is one of the main challenges of last
years. Security Information and Event Management (SIEM) systems are widely used
for coping with this challenge. However, they currently present several
limitations that have to be overcome. In this paper we propose an enhanced SIEM
system in which we have introduced novel components to i) enable multiple layer
data analysis; ii) resolve conflicts among security policies, and discover
unauthorized data paths in such a way to be able to reconfigure network
devices. Furthermore, the system is enriched by a Resilient Event Storage that
ensures integrity and unforgeability of events stored.
