W32.Opaserv.K.Worm - Removal

NOTES

• These removal instructions are useful only if the payload has not run. If the payload has run and you saw the "Illegal Microsoft Windows license detected" message, as described in the previous section, it is possible that your computer is no longer functional.
• If you can no longer start your computer, we suggest that you contact the computer's manufacturer for assistance. You may have to repartition the hard drive, and re-install the operating system. You will also need to restore data from a clean backup.

READ THIS FIRST

• This worm uses a security vulnerability in Microsoft Windows 95/98/Me. It sends single-character passwords to network shares to get access to the Windows 95/98/Me file shares, without knowing all the passwords assigned to the shares. The affected systems include Windows 95, 98, and Me.
  
  A patch for computers that run these operating systems can be found at http://www.microsoft.com/technet/security/bulletin/MS00-072.asp. If you have not already done so, obtain and install the patch to prevent future infections.
• If you are on a network, or if you have a full-time connection to the Internet, such as a DSL or cable modem, disconnect the computer from the network and the Internet. Disable sharing before you reconnect computers to the network or to the Internet. Because this worm spreads by using shared folders on networked computers, to ensure that the worm does not re-infect the computer after it has been removed, remove all the shares, clean all the computers on the network, patch all the systems, and update the definitions on all the computers before you reconnect to the network or re-enable shares. For instructions, refer to your Windows documentation, or the document, "How to configure shared Windows folders for maximum network protection."
• If you are removing an infection on a network, first make sure that all the shares are disabled.

Removal using the W32.Opaserv.Worm Removal Tool
This is the easiest way to remove this threat. Symantec Security Response has created a W32.Opaserv.Worm Removal Tool. Click here to obtain the tool. This removal tool can remove all the discovered variants of W32.Opaserv.Worm through W32.Opaserv.K.Worm.

Manual Removal
As an alternative to using the removal tool, you can manually remove this threat as well. These instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

Perform the following steps to remove the W32.Opaserv.K.Worm:

1. Disconnect from the network.
2. Update the virus definitions.
3. Do one of the following:
   • Windows 95/98/Me: Restart the computer in Safe mode.
   • Windows NT/2000/XP: Stop the process of running the worm.
4. Run a full system scan and delete all the files detected as W32.Opaserv.K.Worm.
5. Reverse the changes the worm made to the registry.
6. For Windows 95/98/Me only, delete the line:
   
   run=c:\windows\mqbkup.exe
   
   from C:\Windows\Win.ini.

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

1. Disconnecting from the network
If you are on a network, or if you have a full-time connection to the Internet, such as a DSL or cable modem, disconnect the computer from the network and the Internet. Disable sharing before reconnecting computers to the network or to the Internet. Because this worm spreads by using shared folders on networked computers, to ensure that the worm does not re-infect the computer after it has been removed, remove all the shares, clean all the computers on the network, patch all the systems, and update the definitions on all the computers before you reconnect to the network or re-enable shares. For instructions on how to do this, see your Windows documentation, or the document, "How to configure shared Windows folders for maximum network protection."

IMPORTANT! Do not skip this step.

1. Disconnect from the network before attempting to remove this worm.
2. For additional information on file sharing, read your Windows documentation, or the document, "How to configure shared Windows folders for maximum network protection."
3. If you are running Windows 95/98/Me, download and install the Microsoft patch from http://www.microsoft.com/technet/security/bulletin/MS00-072.asp.
4. When you have finished the removal procedure, if you decide to re-enable file sharing, Symantec suggests that you do not share the root of drive C. Instead, share the specific folders. These shared folders must be password-protected with a secure password. Do not use a blank password.
   

2. 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 the 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), in the "Protection" section, at the top of this writeup.
• 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), in the "Protection" section, at the top of this writeup.
  
  The Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

3. Restarting the computer in Safe mode or ending the Trojan process

• Windows 95/98/Me
  Restart the computer in Safe mode. All the Windows 32-bit operating systems, except for Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document, "How to start the computer in Safe Mode."
  
• Windows NT/2000/XP
  To end the Trojan process:
  1. Press Ctrl+Alt+Delete once.
  2. Click Task Manager.
  3. Click the Processes tab.
  4. Double-click the Image Name column header to alphabetically sort the processes.
  5. Scroll through the list and look for Mqbkup.exe.
  6. If you find the file, click it, and then click End Process.
  7. Exit the Task Manager.

4. 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.Opaserv.K.Worm, click Delete.

5. Reversing the changes the worm made to the registry

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read 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 following key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
4. In the right pane, delete the following value:
   
   mqbkup    %windir%\mqbkup.exe
   
   or:
   
   mqbkupdbs    %windir%\mqbkup.exe
   
5. Exit the Registry Editor.

6. Deleting the line that the worm added to the Win.ini file
This step is necessary on Windows 95/98/Me-based computers only.

NOTE for Windows Me users only: Due to the file-protection process in Windows Me, a backup copy of the file you are to edit exists in the C:\Windows\Recent folder. Symantec recommends that you delete this file before you continue with the steps in this section. To do this using Windows Explorer, go to C:\Windows\Recent, and in the right pane select the Win.ini file and delete it. It will be regenerated as a copy of the file you are to edit when you save your changes to that particular file.

1. Click Start, and then click Run.
2. Type the following:
   
   edit c:\windows\win.ini
   
   Then click OK. (The MS-DOS Editor opens.)
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
3. In the [windows] section of the file, look for an entry similar to:
   
   run=c:\windows\mqbkup.exe
   
4. Select the entire line. Be sure that you have not selected any other text in the file. Then press Delete.
5. Click File, and then click Save.
6. Click File, and then click Exit.

Technical Details