Facebook has fixed a critical flaw in its messaging app Facebook Messenger for Android, which allowed callers to listen to the environment of other users without permission, before the caller accepted the call !!.
Facebook Messenger for Android has over 1 billion installs Appliances Android, according to the official Play Store page of the application.
Intruders could have exploited this error by sending a special type of message known as SdpUpdate, which would cause the call to be connected to the caller's device before it was answered.
Such as explains Natalie Silvanovich, a researcher at Google's Project Zero program “If this message is sent to the called user's device, it will cause the transmission to begin sound immediately while she is still ringing, which could allow an attacker to monitor the caller's environment."
Normally, the recipient of the call does not transmit audio until it agrees to accept the call, which is implemented when it clicks the accept button. Now if all this time someone was calling you a little more persistently than normal, you should probably suspect it. Especially if it was your other half.
Silvanovich found the issue in version 284.0.0.16.119 of Facebook Messenger for Android last month. To exploit this issue, an attacker would need to already have the rights to invite this particular person by bypassing certain eligibility checks (eg, being Facebook friends). It should also know how to use tools reverse-engineered its own Messenger app to force it to send a custom message.
The Facebook awarded to Silvanovich a $ 60.000 donation to find and reveal this Messenger bug for Android.
This year alone, Facebook reports that more than $ 1,98 million was given to researchers from more than 50 countries who reported more than 1.000 vulnerabilities.
