  Coordinated and targeted cyber-attacks to Critical Infrastructures (CIs) are
becoming more and more frequent and sophisticated. This is due to: i) the
recent technology shift towards Commercial Off-The-Shelf (COTS) products, and
ii) new economical and socio-political motivations. In this paper, we discuss
some of the most relevant security issues resulting from the adoption in CIs of
heterogeneous network infrastructures (specifically combining wireless and IP
trunks), and suggest techniques to detect, as well as to counter/mitigate
attacks. We claim that techniques such as those we propose here should be
integrated in future SIEM (Security Information and Event Management)
solutions, and we discuss how we have done so in the EC-funded MASSIF project,
with respect to a real-world CI scenario, specifically a distributed system for
power grid monitoring.
