Drones open new cyber-physical attack vector

Worms, viruses and other malware that spread through unprotected computer networks aren’t the only security threat to the operation of industrial control systems. “Some say that electronic warfare, or the use of directed energy to control the electromagnetic spectrum, attack an enemy, or impede adversary operations, is merging with cyber warfare,” explained Jeff Melrose, principal technology strategist for cybersecurity, Yokogawa, in his session ‘When Drones Attack!’ this week at the company’s North America user group meeting in Orlando. And drones, in particular, represent a new, enabling technology for electronic warfare against industrial facilities.

Melrose cited several examples of industrial process disruptions caused by electromagnetic interferences. In one, the scanning of a naval radar system caused a nearby gas pipeline control system to rapidly cycle a 36-inch valve. “Shock waves induced by the rapid valve movements caused a pipeline rupture,” Melrose explained.

Sure, most would-be miscreants don’t have access to naval-scale radio systems that could interfere with industrial control systems from a distance. But what if a drone is used to bring the source of electromagnetic interference within a plant’s perimeter—even indoors—and far closer to your plant systems?

[sidebar id =1]Melrose has conducted experiments to prove that using a drone to drop an electromagnetic “disruptor” (really just a foil shield) over a wireless transmitter’s antenna is entirely feasible. Further, the autonomous tracking technology of some of today’s drones means they can follow vehicles and workers, staying within electromagnetic distance of their intended targets. Indeed, his calculations indicate that the naval radar-valve scenario described above could be replicated with a relatively inexpensive and readily available jamming device maneuvered to within 10 meters of the target.   

“There’s much we’ve long assumed about vulnerability of systems based on proximity and movement that with the emergence of sophisticated, inexpensive drones is no longer valid,” Melrose said.

To defend against these possibilities, Melrose recommended that users understand the radio frequency spectrum used by their systems. “Major wireless target jammers will leave gaps in electromagnetic inference between certain Wi-Fi channels,” he noted. Mesh networks and other topologies that support redundant signals routes also are to be considered, but may negatively affect battery life. Physical locations where a drone could land and persistently obstruct the Fresnel zone between two antennae may need to be sussed out.