- 04 June 2003
- 13 February 2007
- Also Known As:
- VBS.Zuoning [KAV], VBS/Trads [McAfee]
- Systems Affected:
VBS.Zuoning@mm is a Visual Basic Script (VBS) worm that attempts to mail itself to every contact in the Microsoft Outlook Address Book. The destructive payload is a command to reformat every disk the worm finds when the system is rebooted.
The only known variant does not attach itself to the email it sends, due to a bug. The subject line of the email is "RE : my passwd !please check".
Antivirus Protection Dates
- Initial Rapid Release version 05 June 2003
- Latest Rapid Release version 20 August 2008 revision 017
- Initial Daily Certified version 05 June 2003
- Latest Daily Certified version 20 August 2008 revision 016
- Initial Weekly Certified release date 05 June 2003
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
When VBS.Zuoning@mm is executed, it does the following:
- Copies itself to the following hard-coded locations:
- C:\Windows\Start Menu\Programs\Æô¶_\hell.bmp.vbs
If these drives and folders are not on the system, the files will not be created.
- Overwrites the file, C:\Autoexec.bat, with commands to format every hard drive on the system. The worm sets the Autoexec.bat file attribute to Hidden.
- Creates an empty file, C:\Unzipped\x.txt, if the folder exists.
- Sends mail to every entry in the Outlook address book.
The mail has the following characteristics:
Subject: RE : my passwd !please check
Body: (Due to a bug, the attachment is not added to the mail.)
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
- Disable System Restore (Windows Me/XP).
- Update the virus definitions.
- Run a full system scan and delete all the files detected as VBS.Zuoning@mm.
- If necessary, restore the deleted Autoexec.bat from a backup copy (Windows 95/98/Me).
For specific details on each of these steps, read the following instructions.
1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or 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 one of the following articles:
- "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. 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.
3. Scanning for and deleting the infected files
- 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."
- Run a full system scan.
- If any files are detected as infected with VBS.Zuoning@mm, click Delete.
4. Restoring the deleted files
The malicious Autoexec.bat file is detected as VBS.Zuoning@mm and should have been deleted in step 3. If so, you may need to restore the original version from a backup copy.