He also said that everyone he has shown the app to has expressed emotions from surprised to appalled that both friends and strangers might be able to get their hands on this data which is available online. Khanna had written on Medium that he was surprised that more people hadn’t turned off location settings, a lthough the steps that need to be taken aren’t made clear to people using Facebook’s messenger app. In addition, someone using the Marauders Map extension doesn’t even need to be friends with another Facebook user in order to view their current location or location history, they just need to be part of the same group message. The location history of an individual can be viewed back until the first time they engaged in messaging on Facebook. Time stamps are also included in the JavaScript location data, meaning that movements can be tracked over the course of minutes or hours and can even go back years. Khanna realised that the coordinates are accurate to five decimal places, meaning that he could locate a friend’s college dormitory but go further to locate the room. Using these, the extension can find and display latitude and longitude settings using GPS functionality. Facebook’s default location settings can be toggled on the iOS and Android Facebook Messenger app but have to be manually turned off.
