Android.BackDoor.3105 is the detection name of an originally harmless libcutils.so system library that has been modified in such a way that whenever any program uses it, a malicious library (the backdoor Android.BackDoor.3104) is launched.
The library is located in /system/lib/libcutils.so. A dependency related to the Android.BackDoor.3104 malware has been added into it, so every time any program uses this library, Android.BackDoor.3104, which is located in /system/lib/libmtd.so, is launched.
If the mobile device is operating normally, download and install Dr.Web for Android Light. Run a full system scan and follow recommendations to neutralize the detected threats.
If the mobile device has been locked by Android.Locker ransomware (the message on the screen tells you that you have broken some law or demands a set ransom amount; or you will see some other announcement that prevents you from using the handheld normally), do the following:
Load your smartphone or tablet in the safe mode (depending on the operating system version and specifications of the particular mobile device involved, this procedure can be performed in various ways; seek clarification from the user guide that was shipped with the device, or contact its manufacturer);
Once you have activated safe mode, install the Dr.Web для Android Light onto the infected handheld and run a full scan of the system; follow the steps recommended for neutralizing the threats that have been detected;