Advertisers Might Already Be Using Your Phone’s Hardware to Track You

Recent research has pointed to a method of device fingerprinting that uses the miniscule, unique imperfections in each phone’s accelerometer and gyroscope—basically, its hardware—to create a profile of that phone that can be used to track its user’s activities across the web, without her knowledge. Unlike location data, most sites don’t ask for permission to access a phone’s motion sensors. But this was mostly theoretical, until now.

Many websites already collect this type of information, possibly for advertising purposes, according to new research from investigators at the University of Illinois at Urbana-Champaign and the Hong Kong University of Science and Technology. “We can conclude that motion sensor fingerprinting is a realistic threat to mobile users’ privacy,” the researchers write in a paper. “Smartphone users who use private browsing or clear their cookies to avoid tracking would find that these protection measures are rendered ineffective by fingerprinting, and they can still be tracked,” said Nikita Borisov, one of the study’s authors.