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Discovered: July 12, 2006
Updated: February 13, 2007 12:57:25 PM
Type: Trojan Horse
Systems Affected: Windows

Backdoor.Haxdoor.N is a Trojan horse program that opens a back door on the compromised computer and allows a remote attacker to have unauthorized access.
It also steals passwords and drops a rootkit that will run in safe mode, making this threat difficult to remove.

Antivirus Protection Dates

  • Initial Rapid Release version July 13, 2006
  • Latest Rapid Release version May 07, 2019 revision 006
  • Initial Daily Certified version July 13, 2006
  • Latest Daily Certified version May 07, 2019 revision 008
  • Initial Weekly Certified release date July 19, 2006

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Technical Description

When Backdoor.Haxdoor.N is executed, it performs the following actions:

  1. Drops the following files:

    • %System%\qo.dll
    • %System%\qo.sys
    • %System%\dvb03a.dll
    • %System%\dvb03a.sys
    • %System%\dvb06a.sys

      Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

  2. Creates the following files to store the gathered information:

    • %System%\klo5.sys
    • %System%\lps.dat
    • %System%\dt163.dt
    • %System%\m012741.dat
    • %System%\tn145.dat
    • %System%\rddom.a3d
    • %System%\r85064.dat
    • %System%\wmx.a3d

  3. Hides all of the above files using a rootkit.

  4. Creates the services dvb03a and dvb06a by creating the following registry subkeys:


  5. Hides the services using a rootkit.

  6. Creates the following registry subkey on computers running Windows XP/2000/NT so that it is executed every time Windows starts:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\dvb03a

  7. Creates the following registry subkeys so that it runs in safe mode:


  8. Attempts to hide its presence by injecting dvb03a.dll into the process of explorer.exe and executing a remote thread.

  9. Terminates the following security related processes and attempts to prevent future access by locking them:

    • zapro.exe
    • vsmon.exe
    • jamapp.exe
    • atrack.exe
    • iamapp.exe
    • FwAct.exe
    • mpfagent.exe

  10. Opens a back door on a random TCP port. The remote attacker can then perform the following actions on the compromised computer:

    • Download files
    • Execute programs
    • Control the device driver of the rootkit
    • Steal passwords stored in Protected Storage
    • Steal cached passwords by calling the WNetEnumCachedPasswords API
    • Steal the Miranda IM password
    • Gather dialup connection information
    • Check if webmoney application is installed on the compromised computer
    • Steal ICQ passwords
    • Log keystrokes

  11. May retrieve detailed account information by accessing the following URL with some locally stolen information added as parameters:


  12. Sends an email containing the stolen information to a predetermined email address.


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.


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Restart the computer using the Windows Recovery Console.
  2. Disable System Restore (Windows Me/XP).
  3. Update the virus definitions.
  4. Run a full system scan.
  5. Delete any values added to the registry.
For specific details on each of these steps, read the following instructions.

1. To restart the computer using the Windows Recovery Console
To remove this threat it is necessary to restart the computer and run the Windows Recovery Console. For full details on how to do this please read the Microsoft Knowledge Base article: How to install and use the Recovery Console in Windows XP.
    1. Insert the Windows XP CD-ROM into the CD-ROM drive.
    2. Restart the computer from the CD-ROM drive
    3. Press "R" to start the Recovery Console when the "Welcome to Setup" screen appears.
    4. Select the installation that you want to access from the Recovery Console, if you have a dual-boot computer.
    5. Enter the administrator password
    6. Press Enter
    7. Type cd system32
    8. Press Enter
    9. Type del qo.dll
    10. Press Enter
    11. Type del qo.sys
    12. Press Enter
    13. Type del dvb03a.dll
    14. Press Enter
    15. Type del dvb03a.sys
    16. Press Enter
    17. Type del dvb06a.sys
    18. Press Enter
    19. Type del klo5.sys
    20. Press Enter
    21. Type del lps.dat
    22. Press Enter
    23. Type del dt163.dt
    24. Press Enter
    25. Type del m012741.dat
    26. Press Enter
    27. Type del tn145.dat
    28. Press Enter
    29. Type del rddom.a3d
    30. Press Enter
    31. Type del r85064.dat
    32. Press Enter
    33. Type del wmx.a3d
    34. Press Enter
    35. Type exit
    36. Press Enter. The computer will now restart automatically.
2. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

3. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions:
    • If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.
    • If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.
4. To run a full system scan
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected, follow the instructions displayed by your antivirus program.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

5. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to and delete the following subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\dvb03a

  5. Exit the Registry Editor.

Writeup By: Yousef Hazimee