The safeguarding of critical infrastructures, such as nuclear power plants, electrical power grids, etc, is of primary concern in the aftermath of the 9/11 events in New York. Critical infrastructures are multi-faceted and highly complex collections of technologies that are interlinked and supported through network infrastructures. In such structures, network faults can be triggered by component weaknesses and bad design, but also through malicious actions. These can lead to a cascade of escalating faults, because of cross-infrastructure dependencies, resulting in total system failure.

In this article we are concerned with extreme attacks, that is malicious attacks in which the damage caused is maximal, with no regard to consequences or monetary gain. These attacks target single points of failure, or more generally critical points of failure, and include physical attacks.

We overview the current state of research on the protection of critical infrastructures and propose architectures that will support security and survivability in the presence of extreme threats.