Security researchers from the UNH Cyber Forensics Research & Education Group claim to have identified a vulnerability in the popular app Viber that could compromise the personal information of at least 150 million of the app's users.
Viber allows registered users to share text messages, images, videos and GPS locations, alongside its free voice calling service that is available for Android, iOS, Windows Phone, Blackberry and Desktops .
The researchers found that user data, including images and videos, is stored on Amazon servers in an unencrypted format and could easily be intercepted, as there is no authentication mechanism.
In the video below you can see how it is possible to steal personal data, using a man-in-the-middle attack.

