When you download apps from Google Play Store, they are usually safe and free of malware. This is because Google has a stringent policy against infected apps. However, there are a lot of ways by which your apps could be leaking information about you without your knowledge. For example, your smartphone could be sending out ultrasonic tones right now, and you would not know. These tones would then get picked up by other devices, and this your information could be leaked.
A research team sponsored by the German government found out that more than 230 Android apps secretly tracked users through the use of ultrasonic tones. The team discovered apps that secretly listen for ultrasonic beacons in the background. The so-called ultrasonic tracking beacons could help create profiles of people. Let’s say, for example, that your friend has a smart TV. When you go to watch that TV, the ultrasonic beacon from your phone meets that from the TV. Advertisers connected to both the TV and your phone would learn a little more about you from here.
Google confirmed to CBS News that the identified apps have been either suspended or updated to meet the company’s privacy policies. In order for the apps to use the ultrasonic beacons on your smartphone, you would be notified that the apps will use your phone’s microphones.
The use of ultrasonic beacons is not so widespread. However, the research team noted that cases of these devices being in use have risen from just 6 in April 2015 to 234 this year. Also, four out of the 35 stores visited by the researchers in two European cities use the ultrasonic beacons to track shoppers. Here’s a quote from the report on the subject: “Our findings strengthen our concerns that the deployment of ultrasonic tracking increases in the wild and therefore needs serious attention regarding its privacy consequences”.