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. The worm itself is a Windows PE EXE file about 4Kb in length and written in Assembler. The main worm code is compressed by a built-in aPLib data compression algorithm, so the original worm code is about 6Kb.

The infected messages contain:

Subject: different (see below)
Body: empty HTML message
Attach: whatever.exe
The Subject is randomly constructed from variants (str1 + str2 + ... + str5):


 Fw: Re:


 str2            str3          str4            str5
 ----            ----          ----            ----

 Cool            website       to check        !!      
 Nice            site          for you         !       
 Hot             pics          i found         :-)     
 some            urls          to see          ?!      
 Funny           pictures      here            hehe ;-)
 weird           stuff         - check it              
 funky           mp3s                                
 great           shit                                
 Interesting     music                               
 many            info                                

To run from an infected message, the worm uses a security breach (IFRAME vulnerability, similar to the one used by the "Nimda" worm). So the worm may be activated from infected e-mail simply upon reading or previewing the message.

When an infected file is run, the unpacking routine takes control, unpacks the main worm code into the memory and jumps to it. The main code then sends infected messages to e-mail addresses found in WAB (Windows Address Book). To send e-mails, the worm connects to default the SMTP server.

The worm does not install itself to the system and is not activated anymore (except cases when a user clicks on an attached e-mail again).

The worm has no payload routine and does not manifest itself in any way.

The e-mail spreading routine contains weak mistakes, and it seems the worm is not able to spread under many e-mail client-server configurations.

The most interesting thing about worm is the fact that the activating-and-spreading routine (this is the main routine) is full in just about 3K of executable code.

The worm contains the following text:!ikx2oo1:::
while typing this text i realize this text got added on many av description sites, because this silly worm could be easily a hype. i wonder which av claims '[companyname] stopped high risk worm before it could escape!' or shit like that. heh, or they boycot my virus because of this text. well, it is easy enough for the poor av's to add this worm; since it was only released as source in coderz#2... btw, loveletter*2 power in pure win32asm and only a 4k exe file. heh, vbs kiddies, phear win32asm. :) thx to: bumblebee!29a, asmodeus!ikx. greets to: starzer0!ikx, t-2000!ir, ultras!mtx & sweet gigabyte...btw,burgemeester van sneek: ik zoek nog een baantje...(alignmentfillingtext)

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