Norton Mobile Insight Discovers Facebook Privacy Leak | Symantec Connect Community: Of particular note, Mobile Insight automatically flagged the Facebook application for Android because it leaked the device phone number. The first time you launch the Facebook application, even before logging in, your phone number will be sent over the Internet to Facebook servers. You do not need to provide your phone number, log in, initiate a specific action, or even need a Facebook account for this to happen.
According to Google Play, hundreds of millions of devices have installed the Facebook application and a significant portion of those devices are likely affected.
We reached out to Facebook who investigated the issue and will provide a fix in their next Facebook for Android release. They stated they did not use or process the phone numbers and have deleted them from their servers.
Unfortunately, the Facebook application is not the only application leaking private data or even the worst. We will continue to post information about risky applications to this blog in the upcoming weeks.