A mining Trojan installing itself on the system via the update mechanism of the “Kompiuternyi Zal” program designed to automate computer clubs and cybercafes (ComputerZal.exe (c993afee1c577460d21d544d10d5f74ef18eb0b4)). This program periodically sends a POST request to a PHP script at http://astrumsoft.com/compzal/new_version_check.php. This request contains an application version number and information about the computer.
The server’s response looks as follows:
[-] Described how to configure the automatic log on to system (so computer will not ask for password after reboot/sleep)
[*] "Time out" status shows up to client computers with remaining debt only, otherwise it automatically becomes "Free"
This response with the cut <ENDCOMMENT> string is processed further. In the example, 710 is a command identifier the Trojan uses to perform different actions. For identifiers 800..809, the update.bin file is downloaded from the astrumsoft.com server and saved to the %temp% folder with the "cztemp" or "czt" prefixes. The file name “update.bin” is obfuscated in the code and added to the URL symbol-by-symbol.
For identifier 805, the update.bin file is downloaded and executed.
Once the update.bin program is launched, it closes all "svchostm.exe" and "svcnost.exe" processes, saves the "svcnost.exe" file to the disk and modifies the system registry key [HKLM\Software\Microsoft\Windows\CurrentVersion\Run] to enable automatic execution of the file. In this key, the program registers the 'svchostm’ key. The "svcnost.exe" application is a miner. Data on the wallet, where the mined cryptocurrency is transferred, is hardcoded in the Trojan’s body. The workers’ names for the examined Trojan sample have the "soyuz6_" prefix. The prefix is stored in the malware’s body.
If the operating system (OS) can be loaded (either normally or in safe mode), download Dr.Web Security Space and run a full scan of your computer and removable media you use. More about Dr.Web Security Space.
If you cannot boot the OS, change the BIOS settings to boot your system from a CD or USB drive. Download the image of the emergency system repair disk Dr.Web® LiveDisk , mount it on a USB drive or burn it to a CD/DVD. After booting up with this media, run a full scan and cure all the detected threats.
If the mobile device is operating normally, download and install Dr.Web for Android. 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 for Android onto the infected handheld and run a full scan of the system; follow the steps recommended for neutralizing the threats that have been detected;