Threat Description

VBSWG.AF

Details

Aliases: VBSWG.AF, Lee, Anthrax, Antrax
Category: Malware
Type: Worm
Platform: VBS

Summary



VBSWG.AF is a Visual Basic Script virus found on October 16th, 2001

There has been a virus warning from Anti-Virus vendors calling this VBSWG variant VBS/Antrax (Anthrax). This virus has nothing to do with the old Anthrax virus:

http://www.f-secure.com/v-descs/anthrax.shtml



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details




Variant:VBSWG.AF

This is an IRC worm and a VBS overwriting virus generated with VBSWG virus kit.

VBSWG.AF is written to spread vie email using Outlook Application but it fails to send the script code as an attachment. Therefore it sends only clean message with the following contents:

  Subject:    Antrax Info

   Body:

  si no sabes que es el antrax o cuales son sus efectos aquite
    mando una foto para que veas los efectos que tiene.
  Nota:la foto esta un poco fuerte.


Since the mass-mailing routine fails to send the script code as an attachment (antraxinfo.vbs), VBSWG.AF does not spreads via email.

After this the virus adds a registry key 'Antrax' and uses it as an infection marker so it will not try to excecute the mass-mailing routine again on already infected machines.

However VBSWG is able to spread via mIRC and Pirch by modifying the script.ini and events.ini respectively.

It also searches for files with extension .VBS and .VBE and overwrite them with its code previously saved as antraxinfo.vbs in Windows System directory.

The virus payload activates on Januarry 26th, when it shows the following message box:

	Antrax Worm By wAsEk


There are four similar variants of this virus. One of them VBSWG.AH is trying to drop and run a file called Antrax.exe which is an email bombber called Achis. For more information about Achis see the description:

http://www.f-secure.com/v-descs/achis.shtml

However because of bugs in its code VBSWG.AH does not work at all.

F-Secure Anti-Virus detects all these variants with the current updates:

http://www.f-secure.com/download-purchase/updates.shtml





Description Created: Analysis: Katrin Tocheva, F-Secure; October, 2001


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