If you use Facebook Messenger on your mobile phone, stalking your exact location is as easy at it can get. Aran Khanna, a student at Harvard College in Computer Science and Mathematics, put up a blog last week explaining how much personal data the Facebook Messenger app revealed about an individual to the people he or she chatted with. A default setting in the app (which can be disabled) allows the location of an individual to be sent along with chat messages. When Khanna realised severalof the messages he had sent his friends on chat had his location attached to it, he wrote a piece of code which uses all the location data from messages and plots it on a map. He named his app after the magical map in the Harry Potter series- the "Marauder's Map". Image source: Aran Khanna's blog "Stalking Your Friends With Facebook Messenger" What he noticed was that when the app was used with the GPS on "the latitude and longitude coordinates of the message locations have more than 5 decimal places of precision, making it possible to pinpoint the sender’s location to less than a meter." "One day when I was chatting frequently with a friend of mine (@tomasreimers) the map allowed me to track his hour by hour locations. At the end of that day the location history on the map closely matched the location history collected by his phone." He tried tracking someone using the code and could not only pin point the exact location of the latter's dorm, but also approximately tell where in the dorm was his room located. If this is not invasive enough, Khanna also found that by going through data of a couple of weeks on the map and looking at the location clusters, figuring out an individual's weekly schedule would also be pretty simple. "With this," he wrote, "you can predict exactly which building he would be in at a given time." "I found that I could even do this for people who I am not Facebook friends with. I am currently in a large active chat to organize poker games with some fellow students, many of whom I am not Facebook friends with. However, I can still track their locations extremely accurately from the messages they send the group," he wrote. The "official" version of the extension Khanna wrote, which he had made available for others to use, has now been deactivated after a request from Facebook, a message on his blog post reads. Read the full blog here: Stalking Your Friends With Facebook Messenger
