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.


Technical Details

This virus infects Word97 documents and spreads via global electronic channels: chat-net mIRC and MS Outlook Express. This is the first known macro virus that uses mIRC and Outlook to spread infection. The virus contains the comments:

W97M/antiMARC by Lord Natas [Codebreakers 98]
with special thanks to Rhape79
"We're just the toys in the hands of another"
The virus code contains 15 macros in one module "Antimarc": antiMARC, mIRCDropper, OE, Delay, AutoClose, AutoExec, AutoOpen, FileClose, FileExit, FileSave, FileSaveAs, ToolsMacro, FileTemplates, ViewVBCode, FormatStyle.

The antiMARC macro is the main virus macro. Other ones are either do-nothing ones (AutoExec), or call this macro to infect Word97 documents. The mIRCDropper macro sends the infected documents to chat-network, the OE macro sends the infected message by using Outlook Express.

The virus replicates in Word environment on activating of any auto-macro except AutoExec, i.e. the virus infects the global macro area and documents on documents opening, closing, saving, saving with new name, on entering the Tools/Macro, File/Templates and other menus. To copy its code the virus uses export/import functions via the SYSTEMMICROSOF.386 file that is created in the Windows directory.

Depending on the system random counter the virus also executes its Chat and Outlook spreading routines. While sending its copy to the Chat the virus uses the MIRC32.EXE utility. It disables mIRC warning messages in the system mIRC C:MIRCMIRC.INI file, creates the infected file C:WINDOWSXXXPASSWORDS.DOC and the script C:MIRCSCRIPT.INI.

The virus script file contains the instructions that send the infected XXXPASSWORDS.DOC file to all users that join the Chat. If there is a message with "marcsux" substring, the virus sends to the host of this message the text: "#gotinfected777 X". The virus also sends the message to the Chat:

marc FuCk YoU FaScIsT
warblade STILL SUCKING MARC's COCK?? eh, sure you do!!
super Hey M0therfux0r, shove X/W up yer fat pimple-covered ass!
super 'We do not support the distribution of virii' - i guess you do now, bitch!
#gotinfected777 Kick Me! - I'm InFeCtEd!
While sending itself by using MS Outlook Express the virus creates random named infected file on the C: drive, selects 20th address in Address Book, creates a new message, fills it with random letters, attaches the infected file and appends the footer line:
J97Z/nagvZNEP ol Ybeq Angnf [Pbqroernxref 98]
This procedure is not language independent and does work only under German version of Outlook Express.

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