Some medical devices, smartphones and internet of things gadgets contain certain types of sensors that are vulnerable to potential hacking using sound waves, says cybersecurity researcher Kevin Fu.
"This is now a risk that all manufacturers should be aware of, and in their hazard analysis, it has to be a part of their cybersecurity risk management," says Fu, explaining findings of a recent research study conducted by the University of Michigan and the University of South Carolina.
The microelectromechanical systems - or MEMS accelerometers - that the research team found to contain these vulnerabilities - are sensors used in various devices to measure acceleration or velocity, and then report those readings to a microprocessor. "What we looked at was the ability to trick these sensors into delivering false readings to the microprocessor by using sound waves," he says in an interview with Information Security Media Group.
"What medical devices contain these sensors is still an open question. But these accelerometers are advertised for use in implantable medical devices," he says. "Now, I don't think we have a 'run for the hills' event here, but there is a risk ... and it's important to mitigate it before the threats become practical."
The main hazard of this sound wave vulnerability is the threat to the integrity and availability of the sensor, he explains. Prior studies by other researchers had found that sound waves can be used to disable these sensors. "What's new here is that it is now known that one can actually damage the integrity of the reading," he says. "If you were trusting this reading to do something automated, such as rate-adapt a pacemaker, perhaps based on changing activity of a patient, you now need a second way to verify the integrity of that reading."
The study lists 20 accelerometers for which the researchers were able to change the output of the sensors using sound waves, Fu says. "In some devices, we found that there is a speaker built in right next to the sensor, which means there is a remote ability to cause these changes without an adversary being near the chip."
Fu recommends that manufacturers assess the researchers' list of accelerometers that contain the sound wave vulnerability "and ask [suppliers] for specific parameters, including the resident frequencies, to understand the risks and mitigations."
In the interview (see audio link below photo), Fu also discusses:
- If the integrity of MEMS accelerometers sensors could be potentially impacted inadvertently by sounds - such as certain musical notes - in seemingly benign environments;
- Whether the integrity and availability of other kinds of sensors are also potentially at risk for manipulation by sound waves;
- Whether organizations or individuals that use devices containing these vulnerable sensors need to take steps to mitigate potential risks.
Fu is associate professor of electrical engineering and computer science at the University of Michigan, where he directs the Archimedes Research Center for Medical Device Security. Previously, he served as an associate professor of computer science and adjunct associate professor of electrical and computer engineering at the University of Massachusetts, Amherst. Fu also has served as a visiting scientist at the Food and Drug Administration, the Beth Israel Deaconess Medical Center, Microsoft Research and Massachusetts Institute of Technology Computer Science and Artificial Intelligence Lab. He's co-founder, CEO and chief scientist at healthcare cybersecurity firm Virta Laboratories.