The fitness tracking app Strava has revealed sensitive information about U.S. military bases and active-duty soldiers around the world in what analysts consider a dangerous security threat.
Strava's data visualization map—which the company released in November, showing all the activity tracked by users of its app—has given away more than three trillion GPS data points, the Guardian reported Sunday.
The app allows people to record their exercise and share it with others. But one subset of Strava users is U.S. military personnel on active duty, including troops serving secretive missions abroad in undisclosed locations.
Nathan Ruser, an analyst with the Institute for United Conflict Analysts, first discovered the revelation over the weekend, and recognized the harm it could cause.
The heatmap "looks very pretty" he wrote, but is "not amazing for Op-Sec"— short for operational security. "U.S. Bases are clearly identifiable and mappable."
"If soldiers use the app like normal people do, by turning it on tracking when they go to do exercise, it could be especially dangerous," Ruser added, noting one track that "looks like it logs a regular jogging route."
Strava's map reveals American military personnel using the app in Afghanistan, Djibouti, and Syria, among other locations.
"In Syria, known coalition (i.e., U.S.) bases light up the night," wrote analyst Tobias Schneider, according to the Guardian. "Some light markers over known Russian positions, no notable coloring for Iranian bases … A lot of people are going to have to sit through lectures come Monday morning."
The map also highlights a lone cyclist taking a ride from Homey Airport, Nevada—the U.S. Air Force base known as Area 51—along the west edge of Groom Lake.
When Strava released its heatmap, the company said that "this update includes six times more data than before—in total 1 billion activities from all Strava data through September 2017. Our global heatmap is the largest, richest, and most beautiful dataset of its kind. It is a direct visualization of Strava's global network of athletes."