Class
Worm
Platform
Win32

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: Worm

Worms spread on computer networks via network resources. Unlike Net-Worms, a user must launch a Worm in order for it to be activated. This kind of worm searches remote computer networks and copies itself to directories that are read/write accessible (if it finds any). Furthermore, these worms either use built-in operating system functions to search for accessible network directories and/or they randomly search for computers on the Internet, connect to them, and attempt to gain full access to the disks of these computers. This category also covers those worms which, for one reason or another, do not fit into any of the other categories defined above (e.g. worms for mobile devices).

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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.

Description

Technical Details

This is a network worm spreading under the Win32 systems with backdoor abilities. This worm was reported "in the wild" in July--August 2000. The worm itself is in a Win32 executable file about 120K in length, written in MS Visual C++.

When an infected file is executed, the worm registers itself in the Windows registry in the auto-start section:

HRLMSOFTWAREMicrosoftWindowsCurrentVersionRun startIE = "filename qazwsx.hsq"

where "filename" is the name of the worm's file (usually - "Notepad.exe", see below). As a result, the worm will be activated each time Windows starts up.

The worm then stays in the system memory as an application (visible in task list) and runs two processes: spreading and backdoor.

The spreading process spreads the worm copy through the local network to drives that are shared for reading/writing. The worm enumerates the network resources and looks for a "WIN" string in their names. If such a string is present in the name (i.e., that is Windows directory on remote computer), the worm looks for NOTEPAD.EXE in there, renames it with NOTE.COM and writes its copy with the NOTEPAD.EXE name.

As a result, on the affected machine, the original NOTEPAD.EXE can be found with the NOTE.COM name (it is used by the worm to run the original Notepad when the worm completes its routines), and the worm's code is present in the NOTEPAD.EXE file. The worm will be activated at the moment a user runs Notepad on the affected machine.

The backdoor routine is quite simple. It supports just a few commands: Run (to run specified file), Upload (to create a file on affected machine) and Quit (terminate the worm routines). There are just three commands, but that is enough to install any other (more powerful) backdoor or any other Trojan/virus on the machine.

The worm also sends a notification to its "host" (worm author?). This is an e-mail message sent to some address in China. The message contains the IP address(es) of the infected machine.

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Find out the statistics of the vulnerabilities spreading in your region on statistics.securelist.com

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