Email-Worm.Win32.Sysnom

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.

Description

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 21Kb in length (compressed by UPX, decompressed size is about 45K), and is written in Visual Basic.

Infected messages contain:

Subject: Good News
Attachment: SoftwareKey.exe

The body is selected from the following three variants:

Wanna remove the I-worms CodeRed, BadTrans, Goner, Updater, etc?
Good news for you because we're giving you a software which removes the latest internet worms in your pc.
Included is your free software from AVP.

Hi! You are a winner of a trip to Iceland.
Included in this message is a software which can help you claim your prize.
See you there!!! Iceland.com

Hi! You have just won yourself a plane ticket to Bali, Indonesia!
Click the attachment to see how to claim your price.
This message is courtesy of YouCanSeeTheWorld.com.

The worm is activated from an infected e-mail only when a user clicks on the attached file. The worm then installs itself to the system, and copies itself to C:WINDOWS directory with the following names:

C:WINDOWSSoftwareKey.exe
C:WINDOWSSYSNOM.EXE
C:WINDOWSSCANREGW.EXE (opriginal SCANREGW file is overwritten by worm copy)

and registers one file in the system registry auto-run key:

HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun System Monitor = c:WINDOWSSYSNOM.EXE

The worm then displays the following message:

and starts its e-mail spreading routine. To send infected messages, the worm uses MS Outlook, sending messages to all addresses found in the Outlook address book.

The worm then opens the "http://www.avp.ch" site with IEXPLORER.EXE, and starts a DoS attack on the "indovirus.8m.com" site.

The worm does not manifest itself in any other ways.

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