How Your Smartphone’s Sensors Enable Tracking

Smartphone with eye

Keeping your data private while surfing the web is a challenge, regardless of what device you’re using. A recent study conducted by at Stanford reveals that mobile devices in particular present a unique challenge because of their sensors.

Security researchers at Stanford were able to uniquely identify smartphones based on their accelerometer. James Temple writes on the SFGate blog that other sensors included on most smartphones would be similarly vulnerable to tracking.

The accelerometer aids smartphones in a variety of functions. Most notably, it is how your smartphone recognizes when you have it turned vertically, for portrait mode, or horizontally, for landscape display. When your phone is sitting still, the accelerometer is still active. It has a reading of numbers representing its current location in space. For example, if your phone is resting on a table, it should have a reading of 1 when it’s face up and -1 when it’s face down. However, that’s not actually the case.

Each smartphone has tiny defects that are unavoidable. They make the accelerometer’s readings off by minuscule amounts so instead of 1 and -1, you’ll actually get something like 1.103234 and -.823432.

Since every smartphone is slightly different in its accelerometer readings, those readings can be used to uniquely identify each device. Without you even knowing it, a website you visit on your mobile browser could capture your accelerometer readings and use them to track your actions online.

The Stanford research team compared accelerometers’ readings to cookies. Many websites save files called cookies to your device so they can identify you and target you with specific ads or other actions.

Your smartphone has other uniquely identifiable quirks as well. Each device’s microphone is also different, so fingerprinting is similarly possible. Radio signal inaccuracies have also been used to identify users and their devices.

The use of these tracking methods could be to market relevant products to you or something more sinister. The challenge for security experts is to determine how best to combat these tactics since they don’t require downloading malicious programs or any actions from the user.

To improve the security on your mobile device or desktop PC, call or come by Geek Rescue. We not only offer a variety of security solutions, but we also fix your devices that aren’t working correctly. Call us at 918-369-4335.

October 15th, 2013