cyber security threats to critical control center assets, said the authors. Radio Frequency (RF) detection systems can be constructed to monitor activity across multiple frequency bands to digitally search for unauthorized access and suspicious activity patterns, at a cost that Kuruganti called “moderately expensive.” Commercial products are also available from companies including AirDefense, Cisco and Kismet that can be used to monitor, locate and control Wi-Fi, or Wireless Fidelity, communication, he added. But as noted in the White Paper, “commercial solutions may not be available for ZigBee, Wireless Hart or ISA100 (other wireless standards) for many years.”

Wireless security threats can come not only through covert activities, of course, but also through approved and inadvertent use of wireless technologies within a control system environment. Several examples are described in the Paper.

Given today’s environment, the authors believe that the best approach to containment of wireless cyber security threats is a defense-in-depth methodology. The approach comes directly out of research that was done at the DOE’s National SCADA Test Bed program, in collaboration with several National Labs, Manges said. The basic idea, he explained, was finding a way to “build a secure system with unsecure components.”

The resulting “onion skin” approach, as Manges called it, involves multiple layers of defense, including personnel controls, physical controls, wireless network controls, wired network controls and containment measures. It has been mathematically shown that an improvement made to one layer results in a linear gain in the degree of protection, Manges noted. But additional layers greatly increase wireless cyber security, he said.“Your level of protection goes up exponentially with the number of layers you have, vs. just improving a single layer.”  The defense in depth approach is described in detail in the White Paper.

To hear a podcast interview with co-authors Tom Flowers, Wayne Manges and Teja Kuruganti, please visit www.automationworld.com/podcast-5311. 

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