W32.HLLW.Nebiwo Removal Tool

Symantec Security Response has developed a removal tool to clean infections of W32.HLLW.Nebiwo. This tool cleans infections based on W32.HLLW.Nebiwo detections known as of April 13, 2003.

What the tool does

The W32.HLLW.Nebiwo Removal Tool does the following:

1. Terminates the W32.HLLW.Nebiwo viral processes.
2. Terminates the viral processes for the dropped Trojans.
3. Deletes the W32.HLLW.Nebiwo files.
4. Deletes the dropped Trojan files.
5. Deletes the registry values, which the worm added, and Trojans.

Switch	Description
/HELP, /H, /?	Displays the help message.
/NOFIXREG	Disables registry repair. (We do not recommend using this switch.)
/SILENT, /S	Enables silent mode.
/LOG=<path name>	Creates a log file where <path name> is the location in which to store the tool's output. By default, this switch creates the log file, FixNebiw.log, within the same folder from which the removal tool was executed.
/MAPPED	Scans mapped network drives. (We do not recommend using this switch. Refer to the Notes below.)
/START	Forces the tool to immediately start scanning.
/EXCLUDE=<path>	Excludes the specified <path> from scanning. (We do not recommend using this switch.)

• Scanning the mapped drives scans the mapped folders only. This action may not include all the folders on the remote computer, leading to missed detections.
• If a viral file is detected on the mapped drive, the removal will fail if a program on the remote computer uses this file.

1. Download the FixNebiw.exe file from:
   
   http://securityresponse.symantec.com/avcenter/FixNebiw.exe
   
2. Save the file to a convenient location, such as your downloads folder or the Windows desktop (or removable media that is known to be uninfected, if possible).
3. To check the authenticity of the digital signature, refer to the section, "Digital signature."
4. Close all the running programs before running the tool.
5. If you are on a network or you have a full-time connection to the Internet, disconnect the computer from the network and the Internet.
6. If you are running Windows Me or XP, then disable System Restore. Refer to the section, "System Restore option in Windows Me/XP," for additional details.
   
   CAUTION: If you are running Windows Me/XP, we strongly recommend that you do not skip this step.
   
7. Double-click the FixNebiw.exe file to start the removal tool.
8. Click Start to begin the process, and then allow the tool to run.
9. Restart the computer.
10. Run the removal tool again to ensure that the system is clean.
11. If you are running Windows Me/XP, then re-enable System Restore.
12. Run LiveUpdate to make sure that you are using the most current virus definitions.

• Total number of the scanned files.
• Number of deleted files.
• Number of terminated viral processes.
• Number of fixed registry entries.

1. Go to http://www.wmsoftware.com/free.htm.
   
   
2. Download and save the chktrust.exe file to the same folder where you saved FixNebiw.exe (for example, C:\Downloads).
   
   
3. Depending on your operating system, do one of the following:
   • Click Start, point to Programs, and click MS-DOS Prompt.
   • Click Start, point to Programs, click Accessories, and then click Command Prompt.
     
     
     
4. Change to the folder where FixNebiw.exe and Chktrust.exe are stored, and then type:
   
   chktrust -i FixNebiw.exe
   
   For example, if you saved the file to the C:\Downloads folder, you would enter the following commands:
   
   cd\
   cd downloads
   chktrust -i FixNebiw.exe
   
   Press Enter after typing each command. If the digital signature is valid, you will see the following:
   
   Do you want to install and run "W32.HLLW.Nebiwo Removal Tool" signed on 4/14/2003 6:58 PM and distributed by Symantec Corporation?
   
   NOTES:
   • The date and time displayed in this dialog box will be adjusted to your time zone if your computer is not set to the Pacific time zone.
   • If you are using Daylight Saving time, the displayed time will be exactly one hour earlier.
   • If this dialog box does not appear, there are two possible reasons:
     • The tool is not from Symantec: Unless you are sure that the tool is legitimate and that you downloaded it from the legitimate Symantec Web site, do not run it.
     • The tool is from Symantec and is legitimate, however, your operating system was previously instructed to always trust content from Symantec: For information on this and how to view the confirmation dialog again, read the document, "How to restore the Publisher Authenticity confirmation dialog box."
       
       
5. Click Yes to close the dialog box.
   
   
6. Type exit, and then press Enter. This will close the MS-DOS session.

• How to disable or enable Windows Me System Restore.
• How to disable or enable Windows XP System Restore.

1. Insert the floppy disk, which contains the FixNebiw.exe file, in the floppy disk drive.
2. Click Start, and then click Run.
3. Type the following:
   
   a:\fixnebiw.exe
   
   and then click OK:
   
   NOTES:
   • There are no spaces in the command, a:\fixnebiw.exe.
   • If you are using Windows Me and System Restore remains enabled, you will see a warning message. You can choose to run the removal tool with the System Restore option enabled or exit the removal tool.
     
4. Click Start to begin the process, and then allow the tool to run.
5. If you are using Windows Me, then re-enable System Restore.

Revision History:

April 16, 2003: Version 1.0 posted.

Write-up by: Brian Ewell