Android.DownLoader.3894

SHA1 hashes:

ac3dff8e8f58c9e1fc27e48f83819257d6553169—rsota.apk (“Software Update” app, com.redstone.ota.ui)
00712a8154c7d399ff1905cdab34a73a1bdbde9d—rsota.odex

Description

The detection name for the trojan code that is built into the Android devices firmware updating system app. This code, for example, was found in the firmware of the Elari Kidphone 4G smart watch. However, it can be present on other device models and types. The main functionality of this code is spread between separate modules that it launches during its operation.

Operating routine

The trojan components, libcore64.jar (Android.DownLoader.812.origin) and libcore.jar (Android.DownLoader.1049.origin), are encrypted and located inside the main app. Upon the device’s first launch, Android.DownLoader.3894 decrypts and launches them. It also controls their integrity: if one of the modules will be missing when the device is powered on again, the trojan will decrypt and activate it again.

The Android.DownLoader.3894 sets the following broadcast receivers to launch the modules automatically:

android.intent.action.BOOT_COMPLETED—device power on
android.net.conn.CONNECTIVITY_CHANGE—network connection change

More details on Android.DownLoader.812.origin
More details on Android.DownLoader.1049.origin
News about the trojan

Curing recommendations

Android

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;
- Switch off your device and turn it on as normal.

Find out more about Dr.Web for Android