More than 70% of smartphone apps are reporting personal data to third-party tracking companies like Google Analytics, the Facebook Graph API or Crashlytics, warns a new study.
When people install a new Android or iOS app, it asks the user's permission before accessing personal information. Some of the information these apps are collecting are necessary for them to work properly: A map app wouldn't be nearly as useful if it couldn't use GPS data to get a location.
But once an app has permission to collect that information, it can share your data with anyone the app's developer wants to -- letting third-party companies track where you are, how fast you are moving and what you are doing.
To get a picture of what data are being collected and transmitted from people's smartphones, the researchers from IMDEA Networks Institute in Spain developed a free Android app of their own, called the Lumen Privacy Monitor.
It analyses the traffic apps send out, to report which applications and online services actively harvest personal data.
Because Lumen is about transparency, a phone user can see the information installed apps collect in real time and with whom they share these data.
"We try to show the details of apps' hidden behaviour in an easy-to-understand way. It's about research, too, so we ask users if they'll allow us to collect some data about what Lumen observes their apps are doing - but that doesn't include any personal or privacy-sensitive data," the researchers said in a statement released by the institute.
This unique access to data allowed the researchers to study how mobile apps collect users' personal data and with whom they share data at an unprecedented scale.
More than 1,600 people who have used Lumen since October 2015 allowed the researchers to analyse more than 5,000 apps.
"We discovered 598 internet sites likely to be tracking users for advertising purposes, including social media services like Facebook, large internet companies like Google and Yahoo, and online marketing companies under the umbrella of internet service providers like Verizon Wireless," the study said.
More than 70 per cent of the apps were connected to at least one tracker, and 15 per cent of them were connected to five or more trackers, the findings showed.
"Tracking users on their mobile devices is just part of a larger problem. More than half of the app-trackers we identified also track users through websites. Thanks to this technique, called 'cross-device' tracking, these services can build a much more complete profile of your online persona," the researchers said.