This Coin-Sized Device Can Hack a Boeing 737

Summary

Security researchers have developed a coin-sized, Wi-Fi-enabled device costing less than $100 that can compromise a Boeing 737's autopilot system. The device can be plugged into an externally accessible port in under a minute, allowing attackers to redirect navigation or alter critical flight calculations, potentially leading to catastrophic outcomes. The researchers have shared their findings with Boeing, which has reviewed its systems in response.

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CommentLoaderSave StorySave this storyCommentLoaderSave StorySave this storyEven as the digital components of so many life-critical systems have proven susceptible to cybersabotage—cars, medical devices, even water utilities and power grids—the computer systems of airplanes have, thankfully, remained uniquely inaccessible to hackers. But one group of academic researchers has spent years testing a different, devious approach to aviation cybersecurity. Perhaps, they suggest, a plane could be hacked the same way that spies and saboteurs have targeted other high-value, offline computers: by surreptitiously gaining physical access to one and plugging in a device designed to silently run the attackers' malicious code.Tomorrow at the Usenix Cybersecurity Conference, researchers from the University of California at San Diego and Oberlin College will present a hacking technique capable of commandeering the autopilot of a Boeing 737 to redirect its navigation or silently altering key values in the plane's takeoff and fuel calculations while spoofing the results on the pilot's screen—subtle changes the researchers say could potentially cause anything from runway overruns on takeoff to diversions to a different country's airspace to catastrophic crashes.To carry out that hacking, they've built a roughly coin-sized, Wi-Fi-enabled prototype device that costs less than $100. In less than a minute, that hardware implant can be fitted into a port accessible via a hatch on the exterior of the plane, one that's routinely within reach of maintenance workers or other airport and airline staff between flights. Once it's in place, the device can send electrical signals on one of the 737's internal networks to spoof commands to sensitive computer systems that guide its autopilot and show the pilot variables like the plane's total weight and outside air temperature, which play a critical role in a 737's takeoff calculations.The researchers' hacking device, next to a quarter for scale. Photograph Courtesy of UCSDBy proving the viability of that technique, the result of a process that stretched over more than a decade and entailed buying tens of thousands of dollars’ worth of plane components for testing, they hope to show that this sort of physical access hacking represents a practical threat in the hands of well-resourced saboteurs and a significant blind spot in aircraft security. Compared to the traditional threat of simply planting a bomb on a plane, they argue, it's also an approach that would offer an attacker more control, stealth, and deniability.“If you could get 60 seconds with an airplane, what could you do?” asks Stefan Savage, one of the UCSD computer science professors who led the project, describing the question that first motivated their line of research. “Well, it turns out there’s a port that’s externally accessible. You can get to it with no special tools in about 15 seconds. And you can shove in a piece of electronics a little bigger than a quarter that lets you basically tell the autopilot what to do and lie to the pilot about changes to the flight plan.”The hacking device (bottom) next to the connector it fits into on a Boeing 737, one that can be found inside a port that’s accessible from a hatch on the plane’s exterior. Photograph Courtesy of UCSDThe researchers aren't revealing which port they targeted on the 737, nor are they releasing some details of how their hacking device is able to spoof commands to the plane's computers. They've worked closely with Boeing to share their findings, first disclosing elements of their research to the company more than six years ago, and going so far as to test out and demonstrate their attack in a Boeing facility's test lab.When WIRED reached out to Boeing about the researchers' work, it responded in a statement that it had carried out its own review of its components' designs, installations, and interfaces in response to the researchers' findings. But it downplayed the practical risk of their physical-access hacking technique. “Our technical experts are confident that the layers of protection in place on the airplane, including within the system design and the operating environment, provide sufficient mitigation to significantly limit the feasibility and risk of real-world attacks,” the statement reads.For their part, the researchers say, Boeing hasn't told them about any technical fix for the vulnerabilities they've discovered—and they speculate that the company may not in fact implement any such update to their systems for years to come, given how rarely commercial airplanes are redesigned.That lack of an immediate security update for planes shouldn't be cause for panic or grounding aircraft, they write in their paper. “All of the authors of this paper routinely travel on Boeing 737 aircraft and expect to continue doing so,” the introduction of the paper reads.Savage argues, though, that the research has demonstrated the need for long-term changes in both the cybersecurity of airplane components and, perhaps more immediately, the operational security measures that determine who can access a plane while it's on the ground. Their simplest fix suggestion: Plug the port with epoxy, or remove it altogether.“This is something the aviation industry will want to plan to defend against,” Savage says. “I would not sleep on this one.”Building a Plane, Then Breaking ItThis particular team of researchers' interest in hacking a plane originated nearly a decade and a half ago, when some of them discovered and demonstrated the first successful over-the-internet techniques for hacking a car's computer systems, including its steering and brakes. Their proof-of-concept attack methods, particularly ones carried out by exploiting a Chevy Impala's OnStar system, launched an era of automotive hacking research that ultimately led to a sea change in carmakers' cybersecurity practices, including launching bug bounty programs for cars and hiring car hackers to help them root out vulnerabilities.In the wake of that car-hacking work, one member of the team, then UCSD research scientist Kirill Levchenko, suggested they try hacking airplanes next. But unlike a Chevy Impala, a Boeing 737 was well beyond their budget. “I pointed out that we can’t exactly buy a plane and put it in the parking lot, but he was undeterred,” Savage says.Over the following years, the team began buying computer components from that commercial aircraft whenever they could find them for sale, spending tens of thousands of dollars to acquire the equipment on the secondhand market. By 2019 they had assembled what they called Triton, an “avionics test bed" that essentially consisted of wired-together 737 computer parts.UCSD professor Aaron Schulman pushing a button on the Flight Management Computer that's part of the researchers' Triton avionics test bed, a collection of wired-together Boeing 737 computer components. Photograph: Erik Jepsen/University of California San DiegoAround the same time, UCSD professor Aaron Schulman was working on another research project on credit card skimmer devices that hackers were physically planting on gas station point-of-sale terminals to steal payment information. “We realized that it's a reasonable threat for someone to plug a device into a bus and read stuff off of it and potentially even gain control of it,” says Schulman, using the term “bus” to mean an internal network connecting components of a piece of digital equipment. Schulman began to wonder if a similar physical access attack might work on the internal bus of a plane. “We were like, ‘Wait a minute, we’ve got to rethink everything.’”With that idea in mind, one of Schulman's then student researchers, Sam Crowe, hunted through hundreds of pages of Boeing wiring diagrams and found that one particular port—typically protected by only a hatch without a lock—connected to a certain 737 bus that carries the data for two crucial computer components on the plane, its Flight Management

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