Android.Vo1d.3

SHA1 hashes:

8399c41b0d24c30391d7fba6b634ba29c0440007 (/system/xbin/wd)
ccf8c0cb83160a20fa4c89b028fb63884f7b6a86 (decrypted payload)

Description

This is a component of the malicious backdoor Android.Vo1d, which was detected in the system storage area of a number of Android-based TV box models. Its functionality includes:

Decrypting the payload;
Decrypting and launching a daemon;
Downloading and running binary files from target URLs;
Installing and running apps.

Operating routine

Decrypting the payload

The Android.Vo1d.3 decrypts an intermediate object from its body. This object is then loaded into the RAM. It uses the XXTEA algorithm with the key fPNH830ES23QOPIM*&S955(2WR@L*&GF to decrypt this payload.

Launching the daemon

Android.Vo1d.3 decrypts the Android.Vo1d.5 daemon from the previously decrypted payload. For this, it uses the XXTEA algorithm with the key d99202373076ee9ec1d3df1dfa5afe1f. The resulting file is copied to /data/google/daemon and then launched.

Installing and running apps

Android.Vo1d.3 uses Inotify (a Linux kernel subsystem) to monitor the emergence of new files in the following directories:

/data/google/
/data/data/com.goog1e.apps/

The APK program files detected in these directories are installed using the command pm install –user.

Next, the command am start start -n com.google.android.services/.MainActivity is used to run these apps.

Indicators of compromise

More details on Android.Vo1d.5

News article 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