Telegram feature exposes your precise address to hackers
If you’re using an Android device—or in some cases an iPhone—the Telegram messenger makes it easy for hackers to find your precise location when you enable a feature that allows users who are geographically close to you. The researcher who discovered the disclosure vulnerability and privately reported it to Telegram developers said they have no plans to fix it.
The problem stems from a feature called People Nearby. By default, it’s turned off. When users enable it, their geographic distance is shown to other people who have it turned on and are in (or are spoofing) the same geographic region. When People Nearby is used as designed, it’s a useful feature with few if any privacy concerns. After all, a notification that someone is 1 kilometer or 600 meters away still leaves stalkers guessing where, precisely, you are.
Stalking made simple
Independent researcher Ahmed Hassan, however, has shown how the feature can be abused to divulge exactly where you are. Using readily available software and a rooted Android device, he’s able to spoof the location his device reports to Telegram servers. By using just three different locations and measuring the corresponding distance reported by People Nearby, he’s able to pinpoint a user’s precise location.
Source : https://arstechnica.com/?p=1733117