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Added to the Dr.Web virus database: 2014-09-05

Virus description added:

Multi-purpose and multi-module backdoor Trojan written in С. It is spread by means of Trojan.Siggen6.31836. This malware possesses the ability to:

  • run a FTP server on an infected computer;
  • run a SOCKS 5 proxy server on an infected computer;
  • modify the RDP protocol to provide remote access to the infected computer;
  • log keystrokes on an infected PC (keylogging);
  • set feedback with an infected PC for FTP, RDP and Socks5 if the network uses NAT (backconnect);
  • intercept data by PCRE patterns (Perl Compatible Regular Expressions)—a library that implements the regular expression in Perl; for this reason the Trojan intercepts all possible features associated with web surfing;
  • intercept SCard's tokens;
  • inject arbitrary content into web pages loaded in browser windows (web injections);
  • intercept various system functions, depending on the accepted configuration file;
  • modify the code of the running process, depending on the accepted configuration file;
  • interact with the various functional modules (plug-ins);
  • take screenshots;
  • search in the infected system for private keys.

BackDoor.Yebot utilizes standard HTTP protocol as well as native binary protocol to exchange data with the command and control server. Examples of HTTP requests:


Repacked Trojan.Siggen6.31836 is uploaded upon this request.


The request of a configuration file encrypted with RC4 algorithm, that has the following structure after decrypting:

<?xml version="1.0" encoding="utf-8"?>
<task taskid="49">
<params />
<task taskid="525">

The request to load additional modules (plug-ins):

http://46.***.***.94/tp/i.html?m=<имя плагина>&b=98B22416&s=0&c=98B22416

The request to require a list of command and control servers:


Trojan's report on task's execution:


Trojan's report with information about the bot's version:


The binary protocol, employed by the backdoor, has the following title:

struct thead
  BYTE magic[16]; //some_magic_code1
  DWORD d1; //0
  DWORD Bid;
  DWORD d3; //0

The following information is about the type of the forwarded message:

#pragma pack(push, 1)
struct tbody1
  DWORD Size; //message size SizeData+2
  WORD Op; //command number
struct tbody2
  DWORD Flag; 
  WORD Op; //command number
  DWORD Size; //message size SizeData
#pragma pack(pop)

Next, the data is transmitted, the message size corresponds to the parameter specified by the variable SizeData. The following commands are supported:

  • 450—create a new user with the specified name in the system;
  • 351, 352—change PCRE rules for data interception;
  • 108—download and run the plug-in in computer's memory;
  • 102,105—set the configuration to modify the Remote Desktop Protocol (RDP);
  • 400—set the configuration for web injects;
  • 777—prepare specified reports;
  • 200—send information on the infected machine to the command and control server;
  • 350—send stolen keys and data to the command and control server.

The Trojan's C&C server employs the paranoid settings: e.g., it can add an IP address into a black list when the request is incorrect or there are too many requests from a single IP address.

News about the Trojan

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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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