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: Email-Worm

Email-Worms spread via email. The worm sends a copy of itself as an attachment to an email message or a link to its file on a network resource (e.g. a URL to an infected file on a compromised website or a hacker-owned website). In the first case, the worm code activates when the infected attachment is opened (launched). In the second case, the code is activated when the link to the infected file is opened. In both case, the result is the same: the worm code is activated. Email-Worms use a range of methods to send infected emails. The most common are: using a direct connection to a SMTP server using the email directory built into the worm’s code using MS Outlook services using Windows MAPI functions. Email-Worms use a number of different sources to find email addresses to which infected emails will be sent: the address book in MS Outlook a WAB address database .txt files stored on the hard drive: the worm can identify which strings in text files are email addresses emails in the inbox (some Email-Worms even “reply” to emails found in the inbox) Many Email-Worms use more than one of the sources listed above. There are also other sources of email addresses, such as address books associated with web-based email services.

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Platform: Win32

Win32 is an API on Windows NT-based operating systems (Windows XP, Windows 7, etc.) that supports execution of 32-bit applications. One of the most widespread programming platforms in the world.


Technical Details

This is a virus-worm that spreads via the Internet attached to infected e-mails, and sends itself via IRC channels and infects a IIS server. It also protects itself from anti-virus programs.

The worm itself is a Windows PE EXE file, 14336 bytes in length, and is written in Visual Basic 6. It is packed in a UPX program. After unpacking, it is 53 Kb size. It contains the following text strings:

    W32.Karen by Gobo ... happy birthday girl !!! shouts : W1z, Merl, NM, and whoever else. #teamvirus on Undernet ... say hello. bob is the king of bots :)

Infected messages contain the following:

Subject is one from the 15 variants:

  • If I were God and didn't belive in myself would it be blasphemy
  • The A-Team VS KnightRider ... who would win ?
  • Just one kiss, will make it better. just one kiss, and we will be alright.
  • I can't help this longing, comfort me. Li>And I miss you most of all, my darling ...
  • ... When autumn leaves start to fall
  • It's dark in here, you can feel it all around. The underground.
  • I will always be with you sometimes black sometimes white ...
  • .. and there's no need to be scared, you re always on my mind.
  • You just take a giant step, one step higher.
  • The air will hold you if you try, trust my wings of desire. Glory, Glorified.......
  • The horizons lean forward, offering us space to place new steps of change.
  • I like this calm, moments before the storm Darling, when did you fall..when was it over ?
  • Will you meet me .... and we'll fly away ?!

Attach file name is random. It has one from the following extensions:
.exe, .pif, .scr, .bat, .com

Sample names are as follows:


The message body is one the following 4 variants:

  • They say love is blind ... well, the attachment probably proves it. Pretty good either way though, isn't it ?

  • You should like this, it could have been made for you speak to you later

  • Happy Birthday Yeah ok, so it's not yours it's mine :) still cause for a celebration though, check out the details I attached

  • This made me laugh Got some more stuff to tell you later but I can't stop right now so I'll email you later or give you a ring if thats ok ?! Speak to you later


While installing, the worm copies itself to Windows system directory with the name KAREN.EXE and registers that file in system registry auto-run key.

Karen = karen.exe

Spreading via E-mail

To send infected messages, the worm uses MS Outlook and sends messages to all addresses found in the Outlook address book.


Spreading via IRC channels

The worm overwrites the file C:MIRCSCRIPT.INI to the new script file.

This script sends an EXE file to each user joining the infected channel. It also sends the following message:

If this doesn't make you smile, nothing will.

It changes a user's nickname to the following:

karen, worm, virus, sex

The script ignores users that send the texts::

script, infected, dcc, script, infected

It joins the channel #teamvirus if it recives a text with char 'e'.

Infecting IIS server

The worm overwrites the file C:INETPUBWWWROOTDEFAULT.HTM with its code, and copies itself to the directory C:INETPUBWWWROOT with the name WEB.EXE. The new DEFAULT.HTM contains a link to the file WEB.EXE. It also has a text comment:

As a result, the local IIS server is infected by the worm.

Protecting from anti-viral programs

While installing in the computer system, the worm scans the running processes. It checks their names from the following list:



The worm terminates these processes in memory.

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