An unnamed Iranian engineer reportedly working to reverse-engineer a U.S. drone recently captured by Revolutionary Guard forces told a reporter for The Christian Science Monitor that the aircraft was downed through a relatively unsophisticated cyber-attack that tricked its global positioning systems (GPS).

The technique, known as "GPS spoofing," has been around for several years, and the Iranians began studying it in 2007, the engineer reportedly said. The U.S. Department of Energy notes that GPS is widely used, but insecure, although few users have taken note. GPS signals for the U.S. military are similarly insecure, and drones often rely on signals from multiple satellites.

"With spoofing, an adversary provides fake GPS signals. This convinces the GPS receiver that it is located in the wrong place and/or time," the vulnerability assessment team at Argonne National Laboratory explained. "Remarkably, spoofing can be accomplished without having much knowledge about electronics, computers, or GPS itself."

Worse yet for U.S. forces, it's an exploit the Iranians reportedly learned after reverse engineering other U.S. drones they shot down, gaining a key bit of leverage against not just drones, but virtually any U.S. military hardware that depends on the same easily exploited signals.

"By putting noise [jamming] on the communications, you force the bird into autopilot," the engineer reportedly said. "This is where the bird loses its brain."

The military's GPS signals had supposedly been better fortified (PDF) in recent years as engineers learned of countermeasures like spoofing, but the Iranians reportedly overcame that by broadcasting a more powerful GPS signal locally that carried the deceptive coordinates -- a vulnerability that has been well documented (PDF) but not yet solved with current-generation systems.

Lockheed Martin, which made the drone that was captured, has a new-generation of GPS known as GPS III coming out soon. The company says it should help prevent future attempts at spoofing, providing enhanced security for the military and civilian authorities who rely on GPS.

The next generation GPS satellites will also come equipped with directional antennas instead of globe-spanning signals, meaning the military will be able to strengthen their GPS signals 100-fold, making the Iranians' trick much harder to pull off in the future.

Lockheed's first GPS III satellite should be operational by 2014.

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