W32.HLLW.Winur - Removal

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

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as W32.HLLW.Winur. Manually delete C:\Autostart.bat and C:\Ntwrk32.dll if they exist.
3. Reverse the changes that the worm made to the registry.
   

For specific details on each of these procedures, read the following instructions.

1. Updating 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 Virus Definitions (LiveUpdate).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). 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 Virus Definitions (Intelligent Updater).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

2. Scanning for and deleting the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan All Files."
2. Run a full system scan.
3. If any files are detected as infected with W32.HLLW.Winur, click Delete.
4. Using Windows Explorer, look for the files, C:\Autostart.bat and C:\Ntwrk32.dll. Delete them if found.

3. Reversing the changes made to the registry

CAUTION: 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 keys only. Read the document, "How to make a backup of the Windows registry," for instructions.

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 key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   
4. In the right pane, delete the value:
   
   msconfig C:\winrun\msconfig.exe
   
   
5. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
   CurrentVersion\RunServices
   
   
6. In the right pane, delete the value:
   
   winrun c:\winrun\msconfig.exe
   
   
7. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\MessengerService\Policies
   
   
8. In the right pane, delete the value:
   
   "IMWarning"="(M)Warning: The person who you are talking to is infected with a virus. Send him the removal tool that can be found in C:\klez_removal.exe(M)"
   
   
9. If you have KaZaA installed, restore the security settings that you normally use. See step 7 in the "Technical Details" section for a list of modified keys.
   (You may be able to restore many of these settings within the KaZaA program. Refer to your KaZaA documentation for additional information, or contact KaZaA technical support.)
   
   
10. Exit the Registry Editor.

Technical Details