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  3. W32.Klez.H@mm

W32.Klez.H@mm - Removal

Risk Level 2: Low

Discovered:
April 17, 2002
Updated:
February 13, 2007 11:38:50 AM
Also Known As:
W32/Klez.h@MM [McAfee], WORM_KLEZ.H [Trend], WORM_KLEZ.I [Trend], I-Worm.Klez.h [Kaspersky], Klez.H, W32/Klez-H [Sophos], Win32.Klez.H [Computer Associa, W32/Klez.I [Panda], W32/Klez.H@mm [Frisk]
Type:
Worm
Systems Affected:
Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows XP
CVE References:
CVE-2001-0154


Removal using the removal tool
Symantec has provided a tool to remove the infections of all the known variants of W32.Klez and W32.ElKern. Try this removal tool first, as it is the easiest way to remove the threats.

Note on W32.Klez.gen@mm detections
W32.Klez.gen@mm is a generic detection that detects variants of W32.Klez. Computers infected with W32.Klez.gen@mm have most likely been exposed to either W32.Klez.E@mm or W32.Klez.H@mm. If your computer is detected as infected with W32.Klez.gen@mm, download and run the tool. In most cases, the tool will be able to remove the infection.

Manual removal procedure for Windows 95/98/Me

If W32.Klez.H@mm has activated, in most cases you will not be able to start Norton AntiVirus. Once this worm has executed, it can be difficult and time consuming to remove. The procedure you are to use to manually remove the worm varies with the operating system.

Perform the following instructions for your operating system in the order shown below. Do not skip any steps. This procedure has been tested and will work in most cases.


Note: Due to the damage that this worm can do, and depending on the number of times the worm executes, the process may not work in all the cases. If the process does not work, you may need to obtain the services of a computer consultant.


1. Disabling System Restore (Windows Me)
If you are running Windows Me, 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 "How to disable or enable Windows Me System Restore"

Note: When you are completely finished with the removal procedure, and you are satisfied that the threat has been removed, you should re-enable System Restore by following the instructions in the aforementioned document.

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. Downloading virus definitions
3. Restarting the computer in Safe mode or VGA mode
  • For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions on restarting in Safe mode, refer to the document, "How to start the computer in Safe Mode."
  • For Windows NT 4 users, restart the computer in VGA mode.

4. Editing the registry
    You must edit the key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\Run and remove the wink???.exe value, after you write down the exact name of the wink file.

    CAUTION: We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Make sure to modify the specified keys only. Refer to the document, "How to back up the Windows registry," before you proceed.
    1. Click Start, and then click Run. (The Run dialog box appears.)
    2. Type regedit, and then click OK. (The Registry Editor opens.)
    3. Navigate to the following key:

      HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

    4. In the right pane, look for the following values:

      Wink[random characters] %System%\Wink[random characters].exe
      WQK %System%\Wqk.exe


    5. Write down the exact filename of the Wink[random characters].exe file.
    6. Delete the Wink[random characters] value and the WQK value, if it exists.
    7. Navigate to and expand the following key:

      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

    8. In the left pane, under the \Services key, look for the following subkey:

      \Wink[random characters]


      and delete it, if it exists.



      Note: This probably will not exist on Windows 95/98/Me-based computers, but check for it anyway.


    9. Click Registry, and then click Exit.
5. Configuring Windows to show all files
    1. Start Windows Explorer.
    2. Click the View menu (Windows 95/98) or the Tools menu (Windows Me), and then click Options or "Folder options."
    3. Click the View tab.
    4. Uncheck "Hide file extensions for known file types."
    5. Do one of the following:
      • Windows 95: Click "Show all files."
      • Windows 98: In the Advanced settings box, under the "Hidden files" folder, click Show all files.
      • Windows Me: Uncheck "Hide protected operating system files," and under the "Hidden files" folder, click "Show hidden files and folders."

    6. Click Yes if you see a Warning dialog box.
    7. Click Apply, and then click OK.
    6. Deleting the actual Wink[random characters] file
      Using Windows Explorer, open the C:\Windows\System folder and locate the Wink[random characters].exe file. (Depending on your system settings, the .exe extension may not be displayed.)


      Note: If you have Windows installed to a location other than C:\Windows, make the appropriate substitution.

    7. Emptying the Recycle Bin
      Right-click the Recycle Bin on the Windows desktop, and then click Empty Recycle Bin.

    8. Running the Intelligent Updater
      Double-click the file that you downloaded in step 1. Click Yes or OK if prompted.

    9. Restarting the computer
      Shut down the computer, and then turn off the power. Wait 30 seconds, and then restart it.

      CAUTION: This step is crucial, as re-infection will occur if you skip this step.

      Allow the computer to normally start. If any files are detected as infected with W32.Klez.H@mm or W32.Klez.gen@mm, quarantine them. You may find some files, such as Luall.exe, Rescue32.exe, and Nmain.exe.

    10. Scanning with Norton AntiVirus (NAV) from a command line
      Because the worm damaged some NAV files, scan from a command line.


      Note: These instructions are only for Consumer versions of NAV. The Navw32.exe file is not part of the Enterprise versions of NAV, such as NAVCE. The NAVCE command-line scanner, Vpscan.exe, will not remove the worm.

      1. Click Start, and then click Run.
      2. Type, or copy and paste, the following:

        NAVW32.EXE /L /VISIBLE

        and then click OK.

      3. Allow the scan to run. Quarantine any additional files that are detected.

    11. Restarting the computer
      Allow the computer to normally start.

    12. Re-installing NAV
      NOTE: If you are using NAV 2002 on Windows XP, re-installation may not be possible on all the systems. Though, you can try the following:
      • Open the Control Panel.
      • Double-click Administrative Tools.
      • Double-click Services.
        In the list, select the Windows Installer. Click Action, and then click Start.
      To re-install NAV, follow the instructions in the document, "How to restore Norton AntiVirus after removing a virus."
    13. Restarting the computer and rescanning
      1. Shut down the computer and turn off the power. Wait 30 seconds, and then restart it.

        CAUTION: This step is crucial, as re-infection will occur if you skip this step.
      2. Run LiveUpdate and download the most current virus definitions.
      3. Start Norton AntiVirus (NAV) and make sure that NAV is configured to scan all the files. For instructions, read the document "How to configure Norton AntiVirus to scan all files."
      4. Run a full system scan. Quarantine any files detected as infected with W32.Klez.H@mm or W32.Klez.gen@mm.


    Manual removal procedure for Windows 2000/XP

    1. Disabling System Restore
    If you are running 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 "How to turn off or turn on Windows XP System Restore"

    Note: When you are completely finished with the removal procedure, and you are satisfied that the threat has been removed, you should 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. Downloading virus definitions
    3. Restarting the computer in Safe mode 4. Editing the registry
      You must edit the key, HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services, and remove the wink[random characters].exe subkey, after you write down the exact name of the wink file.

      CAUTION: We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Modify the specified keys only. Refer to the document, "How to back up the Windows registry," before you proceed.
      1. Click Start, and then click Run. (The Run dialog box appears.)
      2. Type regedit, and then click OK. (The Registry Editor opens.)
      3. Navigate to the following key:

        HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

      4. In the left pane, under the \Services key, look for the following subkey:

        \Wink[random characters]


      5. Write down the exact filename of the Wink[random characters].exe file.
      6. Delete the Wink[random characters] subkey.
      7. Navigate to the following key:

        HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

      8. In the right pane, look for the following values:

        Wink[random characters] %System%\Wink[random characters].exe
        WQK %System%\Wqk.exe


        and delete them if they exist.

        NOTE: They probably will not exist on Windows 2000/XP-based computers, but check for them anyway.

      9. Click Registry, and then click Exit.

    5. Configuring Windows to show all files
      Do not skip these steps:
      1. Start Windows Explorer.
      2. Click the Tools menu, and then click "Folder options."
      3. Click the View tab.
      4. Uncheck "Hide file extensions for known file types."
      5. Uncheck "Hide protected operating system files," and under the "Hidden files" folder, click "Show hidden files and folders."
      6. Click Apply, and then click OK.

    6. Deleting the actual Wink[random characters] file
      Using Windows Explorer, open the C:\Winnt\System folder and locate the Wink[random characters].exe file. (Depending on your system settings, the .exe extension may not be displayed.)

      NOTE: If you have Windows installed to a location other than C:\Windows, make the appropriate substitution.

    7. Emptying the Recycle Bin
      Right-click the Recycle Bin on the Windows desktop and click Empty Recycle Bin.

    8. Running the Intelligent Updater
      Double-click the file that you downloaded in step 1. Click Yes or OK if you are prompted.

    9. Restarting the computer
      Shut down the computer and turn off the power. Wait 30 seconds, and then restart it.

      CAUTION: This step is crucial, as re-infection will occur if you skip this step.

      Allow the computer to normally start. If any files are detected as infected with W32.Klez.H@mm or W32.Klez.gen@mm, quarantine them. You may find some files, such as Luall.exe, Rescue32.exe, and Nmain.exe.

    10. Scanning with Norton AntiVirus (NAV) from the command line
      Because the worm damaged some NAV files, scan from the command line.

      NOTE: These instructions are only for Consumer versions of NAV. The Navw32.exe file is not part of the Enterprise versions of NAV, such as NAVCE. The NAVCE command-line scanner, Vpscan.exe, will not remove the worm.
      1. Click Start, and then click Run.
      2. Type, or copy and paste, the following:

        NAVW32.EXE /L /VISIBLE

        and then click OK.

      3. Allow the scan to run. Quarantine any additional files that are detected.

    11. Re-installing NAV
      NOTE: If you are using NAV 2002 on Windows XP, re-installation may not be possible on all the systems. Though, you can try the following:
      • Open the Control Panel.
      • Double-click Administrative Tools.
      • Double-click Services.
        In the list, select Windows Installer. Click Action, and then click Start.
    To re-install NAV, follow the instructions in the document, "How to restore Norton AntiVirus after removing a virus."


    12. Restarting the computer and rescanning
      1. Shut down the computer and turn off the power. Wait 30 seconds, and then restart it.

        CAUTION: This step is crucial, as re-infection will occur if you skip this step.
      2. Run LiveUpdate and download the most current virus definitions.
      3. Start Norton AntiVirus (NAV) and make sure that NAV is configured to scan all the files. For instructions, read the document, "How to configure Norton AntiVirus to scan all files."
      4. Run a full system scan. Quarantine any files detected as infected with W32.Klez.H@mm or W32.Klez.gen@mm.



    Writeup By: Neal Hindocha

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