1. Symantec/
  2. Security Response/
  3. Trojan.Tatanarg.B


Risk Level 1: Very Low

May 10, 2012
December 7, 2012 2:56:59 AM
Also Known As:
Troj/Agent-WGW [Sophos], Troj/Agent-WOX [Sophos], Troj/Zbot-DEP [Sophos]
Infection Length:
163,840 bytes
Systems Affected:
The Trojan injects its code into the explorer.exe process.

The Trojan connects to the following locations on port 31439:
www.[DOMAIN NAME]/g.php

Note: [DOMAIN NAME] is variable and subject to change.

The Trojan drops the following file:
%UserProfile%\Application Data\Identities\[RANDOM CLSID]\LicenseValidator.exe

The Trojan creates the following registry subkeys:
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\StartCurrId
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\StartMainId
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\PersistFolder
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\PersistFile
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\StartProcIrq
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\StartMainMask
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\StartCurrMask
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\StartPage\ReserveProgram

The Trojan creates the following registry entry so that it runs every time Windows starts:
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Run\"LicenseValidator" = "%UserProfile%\Application Data\Identities\[RANDOM CLSID]\LicenseValidator.exe"

The Trojan creates the following registry entries:
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\"StartUrlId" = "0"
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\"Browse Files" = "[RANDOM CLSID]"
  • HKEY_CURRENT_USER\Software\Software\Microsoft\Windows\CurrentVersion\Explorer\"Browse Folders" = "[RANDOM CLSID]"

The Trojan then drops modules in bzip+xor form to the following location:
%UserProfile%\Application Data\TeamViewer\[RANDOM CLSID]\[RANDOM CHARACTERS].dat

The Trojan may monitor activity on the following Web browsers in order to capture details of accessed Web pages:
  • Sol
  • Chrome
  • Firefox
  • Internet Explorer
  • Opera
  • Maxthon
  • Netscape Navigator

The Trojan captures sensitive information such as data on all processes running, website browsing history, and details of accessed Internet banking sites, and sends it to the following remote locations:
  • [http://]qualitymayorista.com/swf/[REMOVED]
  • [http://]klthk.cz/pgm/[REMOVED]
  • [http://]www.willowbendfitnessclub.com/com/[REMOVED]
  • [http://]www.go-cube.ch/[REMOVED]

The Trojan may use a fake certificate for man-in-the-middle attacks on banking websites.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Joseph Bingham
Summary| Technical Details| Removal

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