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Another Related Article...Is Your Car Safe From Hackers?Car thieves of the future might be able to get into a car and drive away without forced entry and without needing a physical key, according to new research that will be presented at the Network and Distributed System Security Symposium next month in San Diego, California.
The researchers successfully attacked eight car manufacturers' passive keyless entry and start systems—wireless key fobs that open a car's doors and start the engine by proximity alone.
Srdjan Capkun, an assistant professor of computer science in the system security group at ETH Zurich in Switzerland, who led the work, says he was inspired to investigate the security of keyless entry and start systems after buying a car that had one. Capkun and Aurélien Francillon and Boris Danev, both researchers in the same institution, examined 10 car models from the eight manufacturers. They were able to access all 10 and drive them away by intercepting and relaying signals from the cars to their wireless keys. While they could relay the signals from the key back to the car as well, usually they did not need to because the key transmits its signals up to around 100 meters. The attack works no matter what cryptography and protocols the key and car use to communicate with each other.
Normally, when a wireless key is within a few meters of the right car, it detects a low-powered signal that causes it to issue a command that opens the car enable the ignition. The researchers used a pair of antennas to transmit these signals from the car to the key when the key was farther away, tricking the car into opening without the ordinary authorization. One antenna needs to be very close to the car, and one needs to be within eight meters of the key.
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The researchers came up with two versions of the attack. In one, they ran a cable from near the car to near the key and used it to transmit the signals. They conducted the other wirelessly. Francillon says that the materials for the wired attack cost about $50, and those for the wireless attack cost between $100 and $1,000, depending on the electronic components used.
The researchers tested a few scenarios. An attacker could watch a parking lot and have an accomplice watch as car owners as entered a nearby store. The accomplice would only need to be within eight meters of the targeted owner's key fob, making it easy to avoid arousing suspicion. In another scenario, a car owner might leave a car key on a table near a window. An antenna placed outside the house was able to communicate with the key, allowing the researchers then to start the car parked out front and drive away.
A car won't open or start if the signal from its key takes too long to arrive, so the researchers devised a way to speed communication between their antennas. Most relay attacks require the signals to be converted from analog to digital and back, which takes time. The researchers were able to keep the signals in analog format, which reduced their delay from microseconds to nanoseconds and made their attack more difficult to detect.
The researchers suggest things that car owners and manufacturers can do to protect themselves. Car owners can shield their keys when they're not in use, to prevent attackers from communicating with them. Alternatively, manufacturers could add a button to fobs that would allow owners to deactivate and reactivate them. Capkun worries, however, that these types of solutions detract from the convenience that makes passive keyless entry systems worthwhile.
Ultimately, he says, manufacturers will need to add secure technology that allows the car to confirm that the key is in fact nearby. "I don't see a way around it," Capkun says. His group is actively working on protocols that would accomplish this.
David Wagner, a professor of computer science at the University of California at Berkeley who has studied the cryptographic systems used in keyless entry systems, says the research "should help car manufacturers improve auto security systems in the future."
Wagner doesn't think the research ought to make car owners anxious. "There are probably easier ways to steal cars," he says. But, he adds, a "nasty aspect of high-tech car theft" is that "it doesn't leave any sign of forced entry," so if a thief did use this method to steal a car, he says, it might be hard for police and insurance companies to get sufficient evidence of what happened. Wagner believes that manufacturers, police, and insurance companies all need to prepare for this eventuality.
"Automobiles are a key example of a system that is pervasively computerized," so they need to be thoroughly examined to ensure they are secure, says Tadayoshi Kohno, an assistant professor of computer science at the University of Washington. Kohno helped form the Center for Automotive Embedded Systems Security, which is dedicated to identifying and solving security problems with car security systems before they cause problems in the real world.
This week researchers will present a study showing what could happen if a determined hacker went after the computer systems embedded in cars. The researchers found that, among other things, an attacker could disable the vehicle's brakes, stop its engine, or take control of its door locks. All the attacker needs is access to the federally mandated onboard diagnostics port-- located under the dashboard in almost all cars today.
The researchers point to a recent report showing that a typical luxury sedan now contains about 100 megabytes of code that controls 50 to 70 computers inside the car, most of which communicate over a shared internal network.
"In a lot of car architectures, all the computers are interconnected, so that having taken over one component, there's a substantive risk that you could take over all the rest of them. Once you're in, you're in," says Stefan Savage, an associate professor in the department of computer science and engineering at the University of California, San Diego, who is one of the lead investigators on the project.
The researchers say that their work shouldn't yet be a cause for alarm, mainly because the exploits require access to the inside of a vehicle. But some of these systems can be accessed remotely, and the trend is to add even more wireless connectivity--for example, wireless automatic crash-response systems. The researchers say that other systems, such as satellite radios and remote-controlled door openers, could also become entry points.
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Car systems have surprising interconnections, Savage says. For safety reasons, cars are programmed to unlock the doors after the airbags deploy to help potentially injured passengers exit the vehicle. This turns out to create a connection between the door-locking system and the crash-detection system that an attacker could theoretically exploit.
The researchers investigated the computing systems inside a car without any special knowledge from the manufacturer. They started out by pulling out the hardware and running standard security testing attacks such as fuzzing, which tests software with random input to see if it's possible to induce any glitches or strange behavior. They used the information they gained to craft attacks that could take over and control systems on the car's internal network. They tested their attacks on an immobile car before performing road tests to ensure that their attacks were practical in the real world.
"Until we actually did the live road tests, I don't think we were really able to say that someone could do this to a car on the road," says Tadayoshi Kohno, an assistant professor of computer science and engineering at the University of Washington, and also a lead investigator on the project. Though some of the attacks had to be tweaked at that point, they still functioned.
It's going to be challenging to design more secure systems for cars, Savage says, because many of the techniques commonly used to protect devices won't transfer well. For example, it's common for security systems to shut down computing processes when they detect abnormal behavior. In the case of an electronic braking system, however, shutting it down could be just as dangerous as allowing a corrupted program to keep running.
Savage and Kohno say they plan to work on designing new techniques for securing automotive computer systems through a newly formed Center for Automotive Embedded Systems Security. They hope to work with manufacturers and others with a stake in designing computer systems for cars to make sure their solutions are practical and easy to implement.
One striking thing about the researchers' work is that they found many security systems that were not fully implemented, such as authentication controls that were present but not in use, says HD Moore, chief security officer at Boston company Rapid7 and chief architect of Metasploit, an open-source framework for testing systems for security holes. Moore has also tested some automotive software and found similar problems. "This gives an idea of how immature the industry is," he says, noting that problems will likely worsen as more software extends the reach of the car's internal network.
Kevin Fu, an assistant professor of computer science at the University of Massachusetts Amherst, agrees. "It's probably time for a comprehensive checkup by both industry and regulators on how to provide security assurance for automotive systems with increasingly complex software controls and communication paths," he says.
