Stagefright Exploit is remotely exploitable software bug that affects versions 2.2 (“Froyo”) and newer of the Android operating system. It allows an attacker to perform arbitrary operations on the victim device through remote code execution and privilege escalation.

A new Stagefright threat that targets Android phones through MP3 and MP4 files has been discovered. The code hides within the audio file and activates once users preview it or visit a page where the file is embedded. This audio preview function exists within most versions of Android, so nearly every Android device is susceptible to this exploit. The malicious code can also be sent to a user’s phone via public Wi-Fi.

The bug has been provided with multiple CVE identifiers, CVE-2015-1538, CVE-2015-1539, CVE-2015-3824, CVE-2015-3826, CVE-2015-3827, CVE-2015-3828, CVE-2015-3829 and (the later found) CVE-2015-3864, which are collectively referred to as the Stagefright bug



How to Check if your device is vulnerable to Stagefright

Download stagefright Detector by Zimperium
or
Download Stagefright Detector by Lookout Mobile Security



What to do if your your phone is Vulnerable to Stagefright

1. MMS is the fastest way Stagefright is distributed solution is to go into your messaging app’s settings and turn off auto-retrieve for MMS



2. Whatsapp: WhatsApp is also a way Stagefright is shared especially in group chat, Solution Go to Settings > Chat Settings > Media Auto-Download and make sure video auto-downloads are disabled under ‘When using mobile data’, ‘When connected on Wi-Fi’ and ‘When roaming’. Only download Media files from people you trust



3. As soon as you see a pending update on your device, install it immediately, and use one of the apps above to ensure you are no longer vulnerable. Of course, the apps will offer to provide you with protection if your device is vulnerable, but we have no way of telling how effective that protection is.

source: http://androidnaija.com/stagefright-exploit-android-virus-what-it-is-and-how-to-prevent-it/