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Added to the Dr.Web virus database: 2015-09-11

Virus description added:

SHA1 3cbfa9b48674d7fa4ad0d77d99ae461dc2827b23 (packed)
c8c73bd844d7de3171cd6b8996a224393b941b9c (unpacked)

A Trojan designed to infect POS terminals. This malicious program is, in fact, a “crippled” version of BackDoor.Neutrino.50. Once launched, the Trojan modifies the following registry branch:

1003\Software\Microsoft\Windows\CurrentVersion\Run] 'hh.exe' = '%APPDATA%

The Trojan encompasses a module that checks the infected device's RAM for bank card data. The malicious program sends all acquired bank card data and other intercepted information to the command and control server.

Trojan.MWZLesson can intercept GET and POST requests sent from the infected machine's browsers (Firefox, Chrome or Internet Explorer). Such requests are forwarded to the command and control server run by cybercriminals. Moreover, this malicious program can execute the following commands:

  • CMD—forward the command to the command interpreter (cmd.exe)
  • LOADER—download and run a file (dll—using the regsrv tool, vbs—using the wscript tool, exe—run directly)
  • UPDATE—update itself
  • rate—set a time interval for communication sessions with the command and control server
  • FIND—search documents using a mask
  • DDOS—mount an HTTP Flood attack

Trojan.MWZLesson communicates with the server over the HTTP protocol. The server replies with the 404 error as follows:

<HTML><HEAD><TITLE>404 Not Found</TITLE></HEAD><BODY><H1>Not Found</H1>
The requested URL /css/tasks.php was not found on this server.</BODY></HTML>
<!-- DEBUGc3VjY2Vzcw==ENDOF -->

Data between the DEBUG and ENDOF tags is a message encrypted with base64.

All packages sent by the Trojan are not encrypted. However, if a special cookie parameter is missing from a package, the server ignores it.

Bank card information is sent in the following package:


where type indicates the "Track1" or "Track2" strings,
data indicates bank card information,
p indicates the process name.

Curing recommendations

  1. 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.
  2. 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.
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Download by serial number

Use Dr.Web Anti-virus for macOS to run a full scan of your Mac.

After booting up, run a full scan of all disk partitions with Dr.Web Anti-virus for Linux.

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Download by serial number

  1. 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.
  2. 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;
    • Switch off your device and turn it on as normal.

Find out more about Dr.Web for Android

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