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Discovered: April 06, 2005
Updated: February 13, 2007 12:36:31 PM
Type: Trojan Horse
Systems Affected: Windows

Backdoor.Verify is a back door Trojan that allows unauthorised remote access to the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version April 07, 2005
  • Latest Rapid Release version May 07, 2019 revision 006
  • Initial Daily Certified version April 07, 2005
  • Latest Daily Certified version May 07, 2019 revision 008
  • Initial Weekly Certified release date April 13, 2005

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

Technical Description

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

  1. Copies itself as the following:

    • %System%\MsIdle32.exe - a copy of the Trojan
    • %System%\MsIdle32Hook.dll - a Trojan module that performs keylogging functions
    • %System%\MsSysInfo32.exe - a Trojan module that restarts the MsIdle32.exe process if ended
    • C:\MsBootMgr.exe - a copy of the Trojan

      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. Adds the values:

    "MsIdle32.exe" = "C:\WINNT\system32\MsIdle32.exe"
    "MsBootMgr.exe" = "C:\MsBootMgr.exe"

    to the registry subkey:


    so that Backdoor.Verify runs every time Windows starts.

  3. Adds the value:

    "Shell" = "C:\WINNT\system32\MsIdle32.exe"

    to the registry subkey:

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

    so that Backdoor.Verify runs every time Windows starts.

  4. Modifies the values:

    "EnableFirewall" = "0"
    "DoNotAllowExceptions" = "0"
    "DisableNotifications" = "0"

    in the registry subkey:


    to disable Windows security features.

  5. Creates the following registry entries:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\"C:\WINNT\system32\"MsIdle32.exe" = "C:\WINNT\system32\MsIdle32.exe:*:Enabled:Remote Access"
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Hidden" = "2"
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\"pVF.exe\[default]" = "%System%\MsIdle32.exe"
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\pVF\"pVF_Version" = "822"

    to enable its back door functionalities.

  6. Monitors the following back door components.

    • MsIdle32.exe
    • MsSysInfo32.exe

      If any of these processes are ended, the Trojan restarts it.

  7. Logs keystrokes and system events, and saves the information in the following files:

    • %System%\pMK_kLog.txt
    • %System%\pMK_kLogF.txt
    • %System%\pMK_wLog.txt

      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).

  8. Ends the following security-related processes:

    • VSHWIN32.EXE
    • VSCAN40.EXE
    • VET95.EXE
    • TDS2-NT.EXE
    • TDS2-98.EXE
    • SWEEP95.EXE
    • SERV95.EXE
    • SCAN95.EXE
    • SCAN32.EXE
    • RAV7.EXE
    • F-PROT95.EXE
    • F-PROT.EXE
    • PCCWIN98.EXE
    • PAVW.EXE
    • NVC95.EXE
    • NAVLU32.EXE
    • NAVAPW32.EXE
    • N32SCANW.EXE
    • LOCKDOWN2000.EXE
    • JEDI.EXE
    • IOMON98.EXE
    • ICSUPP95.EXE
    • ICLOAD95.EXE
    • DVP95_0.EXE
    • CLAW95CF.EXE
    • CLAW95.EXE
    • CFINET32.EXE
    • AVWUPD32.EXE
    • AVWIN95.EXE
    • AVPTC32.EXE
    • AVPDOS32.EXE
    • AVNT.EXE
    • AVE32.EXE
    • ACKWIN32.EXE
    • D32.EXE
    • BKAV2002.EXE
    • NAVW32.EXE
    • NAVAPW32.EXE
    • F-AGNT95.EXE
    • WFINDV32.EXE
    • AVPM.EXE
    • AVP32.EXE

  9. Attempts to create copies of itself on all fixed drives in directories containing the following strings:

    • user
    • system
    • book
    • game
    • pic
    • media
    • download
    • upload
    • share
    • music
    • doc
    • program
    • soft

  10. Copies will have one of the following filenames:

    • MU Korea new!!.exe
    • Shower girl.exe
    • _-_Click_-Me!_.exe
    • Microsoft Office 2003 Crack.exe-_-Secret-_-.exe
    • ACDSee 8.0 beta.exe
    • Free telephone.exe
    • I want to say that....exe
    • Age of Empires new !!!.exe
    • MU online-update.exe
    • kiss me.jpg.exe
    • Windows XP update new.exe
    • Mirosoft Windows Longhorn beta test.exe
    • Monster.jpg.exe
    • Love you....exe
    • Hack Yahoo! Pass.exe
    • Linkin' Park.jpg.exe
    • My Diary.doc.exe
    • Top Secret.exe
    • Manga news.html.exe
    • Kid1412.jpg.exe
    • Sherlock Homes.doc.exe
    • Conan Doyle.jpg.exe
    • Ichi shinpo.jpg.exe
    • Yahoo! Smiley new !.exe
    • FiFa WorldCup 2006 Beta.exe
    • Nero 7.0 Full.exe
    • WinRAR 4.0 Full.exe
    • fun fun fun.exe
    • Fantasy XII Update.exe
    • Half-Life 2 Update.exe
    • Windows XP source code.exe
    • Norton Antivirus Update.exe
    • Spy search and destroy new!.exe
    • bikini.jpg.exe
    • UFO.doc.exe
    • The X-files.jpg.exe
    • XXX-Cindy.jpg.exe
    • XXX-Britney Spears.jpg.exe
    • Sexy girl.jpg.exe
    • xxx_Girl.jpg.exe
    • BinLaden PPP.jpg.exefucker.jpg.exe
    • Sweet Valetine.exe
    • Love to kick boot.exe
    • Yahoo! Account Cracker.exe
    • WinAmp 6.0 Full.exe
    • nude_girl.jpg.exe
    • H.O.T news.html.exe
    • ZaiZai smileys.jpg.exe
    • Hillary Duff - nude.jpg.exe
    • Photoshop 9.0 Full.exe
    • Hot Sexxxxx.avi.exe

  11. Opens a back door on TCP port 1906 and 1907 that allows the remote attacker to perform any of the following actions:

    • Display a message on the compromised computer
    • Block and unblock input from the user
    • Beep a number of times
    • Close and eject CD drive
    • Hide, disable, and enable Start Menu
    • Enable and disable Task Manager and Registry tools
    • Send text message to active window
    • List and end processes
    • List and close Windows
    • End antivirus programs
    • Flood the infected computer with messages
    • Set window text
    • Freeze Windows
    • Set Master Volume
    • Play wave and MIDI files
    • View system information about the compromised computer
    • View and clear key log
    • View IP Table
    • Add a user with a blank password
    • Display ftp settings
    • Chat with victim
    • Run programs
    • Send e-mail
    • Download and upload files

  12. Downloads and installs updates to the back door from the following Web sites:

    • [domain removed].com/download/pMK_Veryfun.exe
    • [domain removed].com/rhspyx007/pMK_Veryfun.exe
    • [domain removed].com/rhspyx007/pMK_Veryfun.exe


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. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Delete the Winlogon\shell value from the registry
  4. Restart in safe mode and run a full system scan, deleting all the files detected as Backdoor.Verify.
  5. Delete any values added to the registry.
For specific details on each of these steps, read the following instructions.

1. 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).

2. 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: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the document: Virus Definitions (LiveUpdate).
  • 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 the document: 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.

3. To delete the Winlogon\shell 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.
  4. Navigate to the subkey:

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

  5. In the right panel, delete the value:

    "Shell" = "C:\WINNT\system32\MsIdle32.exe"
  6. Exit regedit

4. To scan for and delete the infected files
  1. Restart computer into safe mode
  2. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  3. Run a full system scan.
  4. If any files are detected as infected with Backdoor.Verify, click Delete.

    After the files are deleted, restart the computer in Normal mode and proceed with section 4.

    Warning messages may be displayed when the computer is restarted, as the threat has not been fully removed at this point. Please ignore these messages and just 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.

  4. Navigate to the subkey:


  5. In the right panel, delete the values:

    "MsIdle32.exe" = "C:\WINNT\system32\MsIdle32.exe"
    "MsBootMgr.exe" = "C:\MsBootMgr.exe"

  6. Navigate to the subkey:


  7. In the right panel, reset the value, if appropriate:

    "EnableFirewall" = "0"
    "DoNotAllowExceptions" = "0"
    "DisableNotifications" = "0"

  8. Navigate to the subkey:


  9. In the right panel, delete the value:

    "C:\WINNT\system32\"MsIdle32.exe" = "C:\WINNT\system32\MsIdle32.exe:*:Enabled:Remote Access"

  10. Navigate to the subkey:


  11. In the right panel, delete the value:

    "Hidden" = "2"

  12. Navigate to the subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths

  13. In the right panel, delete the value:

    "pVF.exe\[default]" = "%System%\MsIdle32.exe"

  14. Navigate to the subkey:


  15. In the right panel, delete the value:

    "pVF_Version" = "822"

  16. Exit the Registry Editor.

Writeup By: Rodney Andres