Threat Explorer

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16 February 2001
13 February 2007
Also Known As:
VBS.Vbswg.gen, I-Worm.Lee.o, VBS/SST@MM
Systems Affected:

VBS.Vbswg.K is created using a worm generator tool, and is detected as VBS.Vbswg.gen. This particular variant spreads by using Microsoft Outlook, mIRC and pirch, and it uses the file name "Neue Tarife.txt.vbs". The mIRC .ini script file is detected as VBS.Vbswg.K (mIRC) and the Pirch .ini script file is detected as VBS.Vbswg.K (pirch).

When spreading by email, this worm presents itself as a message from the German ISP t-online. The attachment is a price list.

When this worm spreads using Microsoft Outlook, all entries in the address book are targeted. The messages have the following attributes:


Neues von Ihrem Internetdienstleister - Robert T. Online informiert


Sehr geehrter Internetsurfer,

es hat sich einiges bei uns getan. Die Telekom kann auch Ihre Internetkosten reduzieren. Wir haben auch für Sie den richtigen Tarif... Damit auch Sie sich entscheiden können, haben wir eine übersicht aller für Sie relevanter Termine an diese eMail gehängt.
Wir sind Sicher, auch Sie werden Ihren Wunschtarif finden.

Bei fragen stehen wir Ihnen natürlich jederzeit zur Verfügung...

Ihr T-Online Service Team


Neue Tarife.txt.vbs

After emailing itself, the virus sets a registry key so that it will not email itself again.

To spread by mIRC, this worm modifies the mIRC file script.ini that is automatically used by mIRC. The viral script.ini file is detected as VBS.Vbswg.K (mIRC).
To spread by pirch, this worm modifies the pirch file events.ini that is automatically used by pirch. The viral events.ini file is detected as VBS.Vbswg.K (pirch).
This worm searches all available drives for mIRC or pirch installations.

Once run, a copy of the worm is stored as \<Windows folder>\Neue Tarife.txt.vbs. The worm then remains running, and if it is deleted, it attempts to recreate itself. Due to a bug in the code, the worm instead recreates itself as a zero-byte file.


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.
  1. Start Norton AntiVirus (NAV), and then run a full system scan, making sure that NAV is set to scan all files.
  2. Delete all files detected as infected by:
    • VBS.Vbswg.gen
    • VBS.Vbswg.K (mIRC)
    • VBS.Vbswg.K (pirch)

Writeup By: Andre Post