My ex wife was terrified of flying. She hinted at this problem but never fully shared her concerns. She also hated being away from me for extended periods of time. So, naturally, when I had a business trip to France I bought her a ticket. The first leg of the trip, to London, was uneventful. When we got there we were greeted by long line, the British love lines, and then were informed that the plane we were supposed to take to France was the subject of a bomb threat. She kind of lost her mind and refused to board a plane that was being screened by people wearing bomb repellent gear. As it turns out there are laws in the UK that state that if you refuse to get on a plane that is being swept for bombs the police can detain you for up to 72 hours to see if you were the person who planted the alleged bomb. So her choices were board the plane or go to jail in a foreign country. She, reluctantly, boarded the plane. To say that the next leg of our trip was tense would be an understatement of epic proportions. It was also on this leg of the trip that she discovered the European fascination with mayonnaise. It was on every sandwich offered. She hates mayonnaise. So I was sitting next to a terrified hungry woman who was learning, rapidly, to loathe Europe. It was not a great way to start a trip.
However, it turns out that her many fears may not have been illusory. Andy Greenberg reports that any terrorist with a cell phone can hijack your next flight.
Here’s an uncomfortable image to keep in mind during your next flight: A rogue hacker who can redirect planes at will with the touch of an Android phone’s screen.
That’s the frightening scenario laid out by Hugo Teso, a security researcher for the German IT consultancy N.Runs, in a presentation at the Hack In The Box security conference in Amsterdam Wednesday. By hijacking a protocol used to send data to commercial aircraft and exploiting bugs in flight management software built by companies including Honeywell, Thales and Rockwell Collins, Teso told the crowd that he could send radio signals to planes that would cause them to execute arbitrary commands such as changes in direction, altitude, speed, and the pilots’ displays.
“You can use this system to modify approximately everything related to the navigation of the plane,” Teso told me in an phone interview following his talk. “That includes a lot of nasty things.”
Read more about the researcher whosays he’s found hackable flaws in airplanes’ navigation systems
Hackers and security researchers have warned for years of vulnerabilities in next-generation air traffic control protocols. But Teso focused on a different protocol called Aircraft Communications Addressing and Report System, (ACARS) a simple data exchange system that has evolved over decades to now include everything from weather data to airline schedules to changes to the plane’s flight management system. (FMS)
Teso says that ACARS still has virtually no authentication features to prevent spoofed commands. But he spent three years reverse engineering the flight navigation software that receives ACARS signals to find bugs that allowed him to send his own commands to the systems, either from a software-defined radio that can be tuned to use ACARS or from a compromised airline system. In his talk, Teso demonstrated an Android application he built that allowed him to redirect a virtual plane with just a tap on a map application running on his Samsung Galaxy phone. “ACARS has no security at all. The airplane has no means to know if the messages it receives are valid or not,” he says. “So they accept them and you can use them to upload data to the airplane that triggers these vulnerabilities. And then it’s game over.”
In his presentation, Teso explained that he experimented on used FMS hardware he bought from eBay and FMS training simulation software that was advertised as containing some or all of the same code as the systems in real planes. In our interview he declined to specify exactly what vulnerabilities he discovered in that code, saying that he has instead contacted the Federal Aviation Administration and the European Aviation Safety Administration, and is working with the affected aerospace companies to fix the problems.
Honeywell, for its part, confirms that it’s been talking to Teso’s employer. But spokesperson Scott Sayres argues that Teso’s work doesn’t necessarily prove any real vulnerabilities in Honeywell’s equipment or software. “We take this seriously and we’re going to work with N.Runs to assess this,” says Sayres. “But as Teso readily admits, the version he used of our flight management system is a publicly available PC simulation, and that doesn’t have the same protections against overwriting or corrupting as our certified flight software.”
Teso’s supervisor at N.Runs, fellow security researcher Roland Ehlies, counters that the vulnerabilities Teso found in the FMS software weren’t related to the PC version he was testing, but rather to functions that would also exist in real planes. “From our perspective it would work with at minimum a bit of adaptation,” he says.
I’ve reached out to Rockwell Collins, Thales, the EASA and the FAA for comment and will offer an update if I hear back from them.
Both Honeywell’s Sayres and Teso agree that even if a hacker were able to alter the FMS through commands remotely sent over ACARS, the pilots of the plane should be able to override those malicious commands with their own valid ones. Nonetheless, Teso said in his presentation that at the very least, a hacker could perform disruptive stunts like causing the cockpits’ lights to blink wildly or the passengers’ pressurized air masks to drop.
Teso’s presentation is far from the first to raise the potential for hackers to disrupt air travel. Two talks at the Black Hat and Defcon security conferences last summer suggested that hackers could spoof or intercept signals sent using the next-generation air traffic control system Automated Dependent Surveillance-Broadcast or ADS-B. That trick might allow an attacker to suddenly generate the appearance of a non-existent plane in a pilot’s direct path, potentially causing chaos in the air.
Tricks with ACARS to disrupt or hijack planes’ flight management systems–if they bear out in real world tests beyond those Teso has performed–could be far more dangerous. Teso believes that the bugs he’s discovered in those navigation systems can be fixed. In the meantime, those in the cockpit would be wise to keep an eye on their autopilot.
General question; why is this software available to the public in the first place? Is there a huge demand for developing homemade auto-pilots? Secondly, why is this research being made public? Terrorists may not have nuclear weapons but they sure as hell have cell phones.
Anyway, the next time you hear a flight attendant telling someone to turn off their cell phone thank them. They may have just saved your life.