NewTech. Spies Can Track You Just by Watching Your Phone’s Power Use
TRACKING. Smartphone users might balk at letting a random app like Candy Crush or Shazam track their every move via GPS. But researchers have found that Android phones reveal information about your location to every app on your device through a different, unlikely data leak: the phone’s power consumption.
Researchers at Stanford University and Israel’s defense research group Rafael have created a technique they call PowerSpy, which they say can gather information about an Android phone’s geolocation merely by tracking its power use over time. That data, unlike GPS or Wi-Fi location tracking, is freely available to any installed app without a requirement to ask the user’s permission. That means it could represent a new method of stealthily determining a user’s movements with as much as 90 percent accuracy—though for now the method only really works when trying to differentiate between a certain number of pre-measured routes.
Spies might trick a surveillance target into downloading a specific app that uses the PowerSpy technique, or less malicious app makers could use its location tracking for advertising purposes, says Yan Michalevski, one of the Stanford researchers. “You could install an application like Angry Birds that communicates over the network but doesn’t ask for any location permissions,” says Michalevski. “It gathers information and sends it back to me to track you in real time, to understand what routes you’ve taken when you drove your car or to know exactly where you are on the route. And it does it all just by reading power consumption.”
PowerSpy takes advantage of the fact that a phone’s cellular transmissions use more power to reach a given cell tower the farther it travels from that tower, or when obstacles like buildings or mountains block its signal. That correlation between battery use and variables like environmental conditions and cell tower distance is strong enough that momentary power drains like a phone conversation or the use of another power-hungry app can be filtered out, Michalevsky says. (Wired)
