A recently discovered a vulnerability in Android can render a phone apparently dead – silent, unable to make calls, with a lifeless screen. For users, this means that their smartphone would have no ring, text or notification sounds.
According to Trend Micro, this vulnerability is present from Android 4.3 (Jelly Bean) up to the current version, Android 5.1.1 (Lollipop). The range of versions currently accounts for more than half of Android devices in use today.
Trend Micro says that no patch has been issued in the Android Open Source Project (AOSP) code by the Android Engineering Team to fix this vulnerability since the company reported it in late May.
The vulnerability lies in the mediaserver service, which is used by Android to index media files that are located on the Android device. This service cannot correctly process a malformed video file using the Matroska container (usually with the .mkv extension).
When the process opens a malformed MKV file, the service may crash (and with it, the rest of the operating system).
This vulnerability can be exploited in two ways: either via a malicious app installed on the device, or through a specially-crafted web site. The first technique can cause long-term effects to the device – an app with an embedded MKV file that registers itself to auto-start whenever the device boots would case the OS to crash every time it is turned on.
Whatever means is used to lure in users, the likely payload is the same. Ransomware is likely to use this vulnerability as a new “threat” for users: in addition to encrypting on the device being encrypted, the device itself would be locked out and unable to be used.
In some ways, this vulnerability is similar to the recently discovered Stagefright vulnerability. Both vulnerabilities are triggered when Android handles media files, although the way these files reach the user differs.
For now, Trend Micro recommends users who have been affected to restart your device in safe mode. Users can also use Trend Micro’s Mobile Security for Android Smartphones and Tablets which provides malicious app detection, protects a user’s data and device, and offers extra security against fake financial and shopping apps.