July 3, 2012 — -- Graduate students from the University of Texas who hijacked a civilian drone aircraft have demonstrated just how easy it would be to redirect unmanned vehicles -- so-called UAVs that someday may do everything from delivering pizza to our doorstep to tracking stolen cars and aiding law enforcement.
The hijacking was done over White Sands, New Mexico, at the request of the U.S. Department of Homeland Security. Officials with the department wanted to know if the students could actually do it.
They did. The department has been reluctant even to talk about it. And the professor behind the capture has mixed emotions.
"I love the idea that I could have takeout food delivered to my doorstep by a drone," engineering professor Todd Humphreys said in a telephone interview. "I'm a sucker for these kinds of advances, so I'm not against drones. I just want to see this done safely."
If the threat isn't addressed quickly, he fears the years ahead may bring chaos in the skies.
The students fed positioning data to a university-owned drone "about the size of a kitchen table" as it hovered over White Sands, Humphreys said. When the signals from the students matched the signals the drone was receiving from a Global Positioning System satellite, the students were able to substitute their data for the satellite's, thus taking complete control of the drone.
All of this without the drone detecting any signs that it was being hijacked.
The students, led by engineering graduate student Daniel Shepard, built the equipment they used for the hijacking, which is known in the GPS community as "spoofing," for about $1,000. But it wasn't exactly easy, according to Humphreys, who directs the Radionavigation Laboratory on the Austin campus.
"It didn't take expensive equipment, but the software took us four years to develop," he said.
It was possible to hijack the drone, he added, because civilian drones are "inherently insecure." The satellite signals used to guide everything from a GPS system on a cell phone to ships at sea are "unencrypted, open, and unauthenticated."
It would be technically possible to fix that, Humphreys said, by modifying the GPS signals, but so far no agency has stepped forward to pay the cost. A so-called "authentication signature" could be added to the signals which would alert the owner if someone is trying to spoof the drone, and the attempted hijacking could be derailed. That would be less intrusive than encrypting all GPS signals, which have become "embedded deeply in our national infrastructure and in our daily lives," Humphreys added.
Military drones are protected by encryption, and it would be far more difficult to commandeer a DOD drone, but that's not to say it couldn't happen.
The CIA launched a spy drone over Iran last December, and it disappeared. Iranians later claimed they had "spoofed" and recovered the drone, but it is not known whether it had a military, or civilian, guidance system.
"I don't think they would be so unwise as to make that a civilian GPS-based drone, but I can't say for sure," Humphreys said. There has been much speculation among experts in the field, but so far little seems to be known about the CIA fiasco.
Humphreys' team has not attempted to hijack a military drone, and even he doubts they could do it. But civilian drones? That's another matter.
Civilian Drones Becoming More Common
There isn't a lot of time to fix this problem. Congress has mandated that the Federal Aviation Administration come up with the rules to allow civilian drones in U.S. airspace by 2015.
And after that, they could be everywhere.
Before May 2, 2000, GPS satellite signals available to civilian receivers were deliberately "degraded," or made less precise, to avoid their misuse. But on that date, "positioning errors that had been the size of a football field turned into errors the size of a small room," Humphreys wrote in an earlier technical report. Today, an inexpensive system can almost pinpoint the position of the receiver.
And that's just the beginning. The GPS community is all abuzz these days with something called "dots." That's just what it sounds like: a receiver no bigger than a dot. They will be everywhere. You will never have to look for your car keys again.
Hijacking a Drone: Safety Questions
So any attempt to tame a technology that is that embedded in our society is going to be difficult.
Hackers have demonstrated they will break any code possible, just because it's there. So there will undoubtedly be many attempts "spoof" not only drones, but also any system that depends on GPS to know where it is.
Humphrey's students have shown that it can be done, although their first attempt focused on a relatively stationary drone. Next, they will try the same trick on a moving drone, which will be considerably more difficult, unless it is moving in a straight course. If it's making evasive movements, it will be harder.
Let's see if they succeed. As Humphrey noted, we all could use a wakeup call.