Class
Email-Worm
Platform
VBS

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: VBS

Visual Basic Scripting Edition (VBScript) is a scripting language interpreted by Windows Script Host. VBScript is widely used to create scripts on Microsoft Windows operating systems.

Description

Technical Details

This internet worm spreads via e-mail messages and sends itself from infected PCs when it is activated. It uses Microsoft Outlook mailing system for sending itself to recipients, whose e-mails are stored in Outlook Address Book.

The worm is written in Visual Basic Script (VBS) programming language. It works only under operating systems with Windows Scripting Host installed (WSH is installed by default in Windows 98 and Windows 2000).

The worm uses a PDF file as a host. The virus code is included in that file as an embedded object, and the worm can be activated only manually.

When a PDF file is opened by the Adobe Acrobat program, (the worm doesn't work in Acrobat Reader), a user is offered to play a simple game, which is stored in an embedded object.

After the embedded object is activated, the Adobe Acrobat (http://www.adobe.com/acrobat) program extracts VBS code, writes it to a tempopary folder and launches it.

The virus code creates a JPG file on a disk and shows it using Internet Explorer.

Then, the worm tries to find its host PDF file on the disk, and if it finds the file, sends it to recipients specified in Outlook Address Book.

For sending itself, the worm randomly chooses an attachment name, message subject and body.

The message subject can contain the following strings:

"You have one minute to find the peach"
"Find the peach"
"Find"
"Peach"
"Joke"

The subject can also contain the "FW:" prefix and an exclamation mark at the end of it.

The message body is assembled from the following sentences:

"Try finding the peach"
"Try this"
"Interesting search"
"I don't usually send this things, but..."

The attachment name may be the following:

"find.pdf"
"peach.pdf"
"find the peach.pdf"
"find_the_peach.pdf"
"joke.pdf"
"search.pdf"

The worm uses a very complex algorithm for sending itself, sometimes resulting in the worm not sending itself at all.

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

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