Discovered: October 16, 2001
Updated: February 13, 2007 11:37:29 AM
Also Known As: VBS/VBSWG.AF, VBS/VBSWG.L
VBS.VBSWG.AF is a Visual Basic Script (VBS) threat that can overwrite .vbe or .vbs files with a copy of itself. It attempts to send itself using MAPI email, but the attempt fails due to bugs in the script.
In an attempt to distribute itself using Internet Relay Chat (IRC), it may also modify existing Script.ini files, which are used by the mIRC program.
Additional precautions that you can take
Some threats, such as this one, use the VBScript computer language to run. You can protect yourself from threats that use this language by enabling Script Blocking (Norton AntiVirus 2001/2002) or by disabling or uninstalling the Windows Scripting Host. Because the Windows Scripting Host is an optional part of Windows, it can be safely removed from your computer. (Some programs, however, need Windows Scripting Host in order to function properly.)
- If you are using Norton AntiVirus 2002, which includes Script Blocking, make sure that Script Blocking is enabled (the default).
- If you are using Norton AntiVirus 2001, a free program update that includes Script Blocking is available. Please run LiveUpdate to obtain this.
- For other versions of Norton AntiVirus, SARC offers a tool to disable the Windows Scripting Host.
- To disable the Windows Scripting Host in Microsoft Outlook Express only, see the Microsoft Knowledge Base document OLEXP: How to Disable Active Scripting in Outlook Express, Article ID: Q192846.
Antivirus Protection Dates
- Initial Rapid Release version March 10, 2001
- Latest Rapid Release version September 28, 2010 revision 054
- Initial Daily Certified version March 10, 2001
- Latest Daily Certified version September 28, 2010 revision 036
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Although, the worm is not successful in its attempts to spread by email due to bugs in its code, the intended format of the email message is as follows:
Subject: Antrax Info
Message: si no sabes que es el antrax o cuales son sus efectos aqui te mando una foto para que veas los efectos que tiene. Nota:la foto esta un poco fuerte.
The following is the English translation of the email message:
If you don't know what anthrax is or what the results of it are, please see the attached picture so that you can see the results that it has. Note: the picture might be too strong.
This script is detected as VBS.VBSWG.L, while other variants may be detected as VBS.VBSWG.gen.
NOTE: There are two other variants of this script, and they are also detected generically.
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.
Run LiveUpdate to make sure that you have the most recent virus definitions.
- Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
- Run a full system scan.
- Delete all files that are detected as VBS.VBSWG.L or a similar detection such as VBS.VBSWG.gen.
Writeup By: Patrick Nolan