Threat Explorer

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VBS.Vbswg2.gen

VBS.Vbswg2.gen

Discovered:
13 March 2001
Updated:
13 February 2007

SARC has become aware of a new worm script generation kit. VBS.Vbswg2.gen is a generic detection for worms created using the worm generator Vbswg 2 (VBS Worm Generator 2). As of this time, SARC has not received any samples of worms generated by this kit.

The retail version of Norton AntiVirus 2001 running on a Windows 9X system will already catch worms generated by this program through a feature called script blocking. In order to activate this feature, users running retail NAV 2001 must manually run LiveUpdate to download the latest definitions. This is done by opening up the NAV console and clicking on LiveUpdate.

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



Norton AntiVirus will also detect the current executable version of this worm generator as VBS.Vbswg2.gen.

Antivirus Protection Dates

  • Initial Rapid Release version 14 March 2001
  • Latest Rapid Release version 08 August 2016 revision 023
  • Initial Daily Certified version 14 March 2001
  • Latest Daily Certified version 09 August 2016 revision 001
  • Initial Weekly Certified release date pending
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Vbswg2 is a VBS worm generator written by an Argentinian virus writer. There are currently at least ten 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 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.

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 worms encrypted with this malicious program as VBS.Vbswg2.gen.

Recommendations

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

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • 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.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a 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.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. 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.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.

  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Start Norton AntiVirus (NAV), and then run a full system scan, making sure that NAV is set to scan all files.
  3. Delete any files detected as VBS.Vbswg2.gen


Writeup By: Brian Ewell