VBS.VBSWG.gen

SUMMARY

VBS.VBSWG.gen is a generic detection for worms created using the worm generator VBSWG (VBS Worm Generator). A recent worm created by this generator is VBS.SST@mm (AnnaKournikova.jpg.vbs). There are currently nine known different versions of VBSWG. Norton Antivirus can detect any worm that uses Microsoft Outlook to propagate itself that can be produced by any of the nine generators. The virus writer that wrote the generators also wrote an encryption program for VBS worms. Norton Antivirus will detect any VBS worm encrypted with this program as VBS.VBSWG.gen.

NOTE: Many of the generated worms will be detected as Bloodhound.VBS.worm

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 12, 2001
• Virus Definitions (Intelligent Updater) February 12, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: More than 1000
• Number of Sites: More than 10
• Geographical Distribution: Medium
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Medium

Distribution

• Distribution Level: High
• Subject of Email: varies
• Name of Attachment: varies
• Size of Attachment: varies

TECHNICAL DETAILS

VBSWG is a VBS worm generator written by an Argentinian virus writer. There are currently nine different known versions of this generator. Many of the versions have bugs in them that causes generated worms to not spread as intended. This mainly applies to the older versions of the generator. Norton AntiVirus will detect any worm that utilizes Microsoft Outlook to propagate that is created with any of these generators.

The generators have many options in them. In the later versions there is also an option to encrypt the generated worm. This is done to avoid detection by antivirus programs. Norton Antivirus will detect any worm that has been generated or encrypted with any version of the generator.

When generating a worm, the author can choose how it should spread, what damage it should cause to the system, if it should have a payload or not. Once the desired malicious options have been chosen, a VBS worm can be generated. A recent example of a worm generated with this generator is VBS.SST@mm.

The Argentinian virus writer that created the worm generators also created a malicious program to encrypt existing VBS Worms. Again, this was done in an attempt to hide from antivirus product. Norton Antivirus will detect any worm encrypted with this malicious program as VBS.VBSWG.gen.

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

NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan, and delete all files that are detected as VBS.VBSWG.gen

For details on how to do this, read the following instructions.

To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. There are two ways to obtain the most recent virus definitions:

• Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
• Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.
  
  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.

To scan for and delete the infected files:

1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
   • Norton AntiVirus consumer products: Read the document How to configure Norton AntiVirus to scan all files.
   • Symantec enterprise antivirus products: Read the document How to verify 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.VBSWG.gen, click Delete.