Backdoor.Nibu.D - Removal

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Restart the computer in Safe mode (Windows 95/98/Me) or Safe mode with Command Prompt (Windows 2000/XP).
4. Reverse the changes made to the registry.
5. Reverse the changes made to the system files (Windows 95/98/Me).
6. Restart the computer in Safe mode or VGA mode (Windows 2000/XP).
7. Run a full system scan and delete all the files detected as Backdoor.Nibu.D.
   

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"
  

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 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.

1. Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer.
2. When you see the black and white Starting Windows bar at the bottom of the screen, press the F8 key (This is usually on the top row of the keyboard).
3. In the Windows 2000 Advanced Options Menu, select Safe mode with Command Prompt, and then press Enter.
   
   Once the computer opens to a window with a command prompt (you should see a line of text and a blinking cursor), proceed with section 4.

1. Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer. The computer will begin processing a set of instructions known as the Basic Input/Output System (BIOS). What is displayed depends on the BIOS manufacturer. Some computers display a progress bar that refers to the word BIOS, while others may not display any indication that this process is occurring.
2. As soon as the BIOS has finished loading, begin tapping the F8 key on your keyboard. Continue to do so until the Windows Advanced Options menu appears. If you begin tapping the F8 key too soon, some computers display a "keyboard error" message. To avoid this, restart the computer and try again.
3. In the Windows 2000 Advanced Options Menu, select Safe mode with Command Prompt and press Enter.
   
   Once the computer opens to a window with a command prompt (you should see a line of text and a blinking cursor), proceed with section 4.

1. Do one of the following:
   • Windows 2000/XP. Skip to step b.
   • Windows 95/98/Me. Click Start, and then click Run.
     
     
2. Type the following:
   
   regedit
   
   
3. Do one of the following:
   • Windows 2000/XP: Press Enter.
   • Windows 95/98/Me: Click OK.
     
     
4. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   
5. In the right pane, delete the value:
   
   "load32"="%System%\swchost.exe"
   
   
6. Do one of the following:
   • Windows 95/98/Me. Skip to step i.
   • Windows NT/2000/XP: Proceed with step g.
     
     
7. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
   
   
8. In the right pane, double-click:
   
   Shell
   
   
9. Change:
   
   "explorer.exe %Windir%\system32\vxdmgr32.exe"
   
   to:
   
   "explorer.exe"
   
   
10. Exit the Registry Editor.
    
11. Do one of the following:
    • Windows 95/98/Me. Proceed with section 5.
    • Windows NT/2000/XP: Skip to section 7.

1. The function you perform depends on your operating system:
   • Windows 95/98: Go to step b.
   • Windows Me: If you are running Windows Me, the Windows Me file-protection process may have made a backup copy of the System.ini and Win.ini files that you need to edit. If these copies exist, they will be in the C:\Windows\Recent folder. Symantec recommends that you delete these files before continuing with the steps in this section. To do this:
     1. Start Windows Explorer.
     2. Browse to and select the C:\Windows\Recent folder.
     3. In the right pane, select the System.ini file and Win.ini files and delete each one. Windows will regenerate the files.
        
        
2. Click Start, and then click Run.
   
   
3. Type the following, and then click OK.
   
   edit c:\windows\system.ini
   
   (The MS-DOS Editor opens.)
   
   Note: If Windows is installed in a different location, make the appropriate path substitution.
   
   
4. In the [boot] section of the file, look for a line similar to:
   
   shell = Explorer.exe C:\WINDOWS\SYSTEM\vxdmgr32.exe
   
   
5. If this line exists, delete everything to the right of:
   
   Explorer.exe
   
   When you are done, it should look like:
   
   shell = Explorer.exe
   
   
6. Click File, and then click Save.
   
   
7. Click File, and then click Exit.
   
   
8. Click Start, and then click Run.
   
   
9. Type the following, and then click OK:
   
   edit c:\windows\win.ini
   
   (The MS-DOS Editor opens.)
   
   Note: If Windows is installed in a different location, make the appropriate path substitution.
   
   
10. In the [windows] section of the file, look for a line similar to:
    
    run=%Windir%\dllreg.exe
    
    
11. If you find it, delete the entire line.
    
    
12. Click File, and then click Save.
    
    
13. Click File, and then click Exit.

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 file."
2. Run a full system scan.
3. If any files are detected as infected with Backdoor.Nibu.D, click Delete.