VBS.VBSWG2.AA@mm

SUMMARY

VBS.VBSWG2.AA@mm is an encrypted VBScript worm that uses Microsoft Outlook to send itself to all recipients in the Microsoft Outlook address book.
The worm also starts the default Web browser and opens a government Web site.

VBS.VBSWG2.AA@mm is an encrypted variant of VBS.VBSWG2, with a simple encryption loop. It was created with the VBSWG2 worm generator.

Note: Definitions dated before 17th of may 2001 will detect this worm as VBS.VBSWG2.Y@mm

Protection

• Virus Definitions (Intelligent Updater) May 15, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low
• Payload: Sends itself to all addresses in the Microsoft address book. Deletes previous emails containing copies of the worm. Opens one of two Web sites on the default browser.
• Large Scale E-mailing: Sends itself to all recipients in the Microsoft Outlook Address Book

Distribution

• Distribution Level: Medium
• Subject of Email: NUEVAS MEDIDAS DEL EJECUTIVO
• Name of Attachment: Batlle_Desnudo.JPG.vbs
• Size of Attachment: 2,215 bytes

TECHNICAL DETAILS

VBS.VBSWG2.AA@mm arrives as an email attachment. When the attachment is executed, it does the following:

1. Decrypts itself and creates a copy of itself as %Temp%Batlle_Desnudo.JPG.vbs.
   
   Note: %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:WindowsTEMP (Windows 95/98/Me/XP) or C:WINNTTemp (Windows NT/2000).
   
   
2. Checks to see if the following registry subkey exists, and if its value is set to 1:
   
   HKEY_CURRENT_USERsoftwareBatllemailed
   
   The worm uses this value to ensure that it only emails itself once from every infected computer.
   
   If the value is not set to 1, the worm uses Microsoft Outlook to mail itself to every address in the Microsoft Outlook address book. The worm then sets the value of the above registry key to 1.
   
   
3. Sends a copy of the worm to all addresses in the Outlook address book. The email is in Spanish (English Translation is in brackets) and has the following characteristics:
   
   Subject: NUEVAS MEDIDAS DEL EJECUTIVO  (NEW EXECUTIVE MEASURES)
   
   Message:
   Lo que nos faltaba:
   Batlle se desnuda para combatir la aftosa !!
   Tenés que verlo, es impresionante!
   
   (What we need right now:
   Battle is undressing to combat the foot and mouth disease !!
   You have to see it, it is impressive!)
   
   Attachment: Batlle_Desnudo.JPG.vbs
   
   
4. Deletes all other copies of the worm in the Microsoft Outlook inbox, and the Deleted Items folder. To do this, it deletes all messages that contain the subject line NUEVAS MEDIDAS DEL EJECUTIVO.
   
   
5. Finally, the worm opens one of two home pages that belong to the Uruguay government.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

REMOVAL

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

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected as VBS.VBSWG2.AA@mm.

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

1. To disable 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"

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.


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 daily. 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. To scan for and delete 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 VBS.VBSWG2.AA@mm, click Delete.
   
   
   Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.
   
   When all the infected files have been deleted, restart the computer in Normal mode.