To the list of vulnerable technologies, it's time to add shipboard GPS. A research
team from the University of Texas at Austin has demonstrated for the first time that a ship's GPS can be tricked.
Todd Humphreys, team leader and assistant professor at UT, told news media that ship captains have "come to trust their electronic chart displays." The onboard chart display tracks unencrypted, civilian GPS signals, but, as this experiment demonstrates, the system is defenseless against counterfeit signals.
Humphreys said that the concept of spoofing a shipboard GPS "has been known for maybe 20 years." The team's briefcase-sized spoofing device, the first publicly acknowledged one of its kind, generates fake GPS signals, which eventually replaced genuine GPS signals received by the custom-built shipboard navigational system on the White Rose of Drachs, a 213-foot, $80 million yacht.
The purpose of the experiment was to see if such a spoofing attack could be carried out at sea and to determine if the ship could detect the fake signals and the altered path. The experiment indicated that the ship's command system, which will generate an alarm if the GPS signal is blocked or jammed, could not differentiate between a fake GPS and an actual GPS signal.
The research team's efforts suggest that hacking could pose a bigger threat than previously recognized for GPS systems of various kinds of vehicles. For instance, in 2012 Humphreys and a team of students were able to similarly capture a GPS-guided unmanned aerial vehicle or drone. The team has also raised the question of whether aircraft, which are commonly operated via autopilot systems, are similarly vulnerable.
Humphreys said in a statement that, "with 90 percent of the world's freight moving across the seas and a great deal of the world's human transportation going across the skies, we have to gain a better understanding of the broader implications of GPS spoofing." He added that it wasn't clear, until the experiment was performed, how feasible it was to "spoof a marine vessel and how difficult it is to detect this attack."
Turning the Ship
The experiment took place last month on the White Rose of Drachs on its voyage from Monaco to Greece in the Mediterranean Sea. The GPS capture occurred while the yacht was 30 miles off the coast of Italy in international waters.
The team broadcast the spoofed GPS signals from the upper deck of the yacht, and were able to slowly overpower the authentic signals as they took control of the vehicle's navigational system. It's not clear from the team's experiment how feasible it would be to similarly hijack a ship's GPS system from a remote location.
When the team gained control of the navigational system, they were able to subtly steer the ship several degrees from its original course. Each time a location discrepancy was reported by the navigational system, the crew undertook a course correction, but the overall result after many course corrections was a somewhat different path than had originally been planned -- hundreds of meters from its intended route.
Humphreys said that "the ship actually turned and we could all feel it, but the chart display and the crew saw only a straight line."