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: IRC-Worm

This type of worm spreads via Internet Relay Chat. Like email worms, IRC Worms have two ways of spreading via IRC channels. The first involves sending an URL which leads to a copy of the worm. The second technique is to send an infected file to an IRC channel user. However, the recipient of the infected file has to accept the file, save it to disk, and open (launch) it.

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Platform: DOS

No platform description


Technical Details

This is an IRC virus-worm that spreads itself via mIRC channels. It appears as a MILBUG_A.EXE DOS EXE file about 10Kb in length. When it is executed, it copies itself to several disk directories under different names:


The worm then infects the installed mIRC client in the C:MIRC directory: it creates a new script file SCRPT.INI and overwrites the MIRC.INI configuration file. If the mIRC client is installed in any other path, the worm fails to infect it.

The worm modifies the MIRC.INI files that customize the mIRC client. There are several options set, for instance a user's identity is set to "kazimas", and the additional script file SCRPT.INI is included in auto-run scripts.

The SCRPT.INI file, that is dropped by the worm, contains several instructions that switch a user to the "Chat2K" channel, send messages to there, and the most important: send to the channel the worm copy (the C:WINDOWSKAZIMAS.EXE file).

The worm also overwrites the C:AUTOEXEC.BAT file with instructions that restore worm's copies (if they are erased) and execution:

@copy c:windowssystempsys.exe c:windowskazimas.exe >nul
@copy c:windowskazimas.exe c:kazimas.exe >nul
@c:kazimas.exe >nul

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