Sports app users often reveal a lot of private information

The popular sports app Strava had more than 100 million users in 195 countries at the end of May 2022. Runtastic by Adidas has 182 million registered users. These are just two examples of the popularity of sports social networking sites. In it, millions of users share their sports activities with friends and other app users.

But the activities they engage in tell a lot about themselves. Often times others can spot patterns: fixed places and times when people exercise, fixed routes, fixed departure and arrival points. It is the latter that are most often living or working spaces.

For example, there have been reports in the past of soldiers inadvertently revealing secret military locations by sharing their running laps. Or reports of athletes having their expensive bikes stolen after thieves lurked in Strava.

In order not to just release that data, social networks like Strava often work with endpoint privacy zones: they allow you to mask off zones around privacy-sensitive sites, in a circle around where you choose to size.

But this approach creates a false sense of security, researchers from the imec-DistriNet group at KU Leuven explain. Researchers say, for example, that apps could better hide information about the distance users travel within privacy zones from strangers, or even delete it altogether. Although the recent intervention has a serious impact on users, as activity is no longer fully logged. Applications can also vary in shape and size of hidden areas (now mostly circles) more.

The researchers have submitted their findings to the respective platforms, and will soon meet with Strava to discuss their suggestions for improvements

As a user, you can also better protect your privacy on sports apps. Setting a privacy area is still a good idea anyway, but make the area around the places you want to hide large enough. Often the minimum is 200 metres, but you can increase the area to over a kilometer. The bigger the better,” stresses researcher Karel Dundt.