1. Symantec/
  2. Security Response/
  3. W32.Badtrans.B@mm


Risk Level 2: Low

November 24, 2001
February 13, 2007 11:37:49 AM
Also Known As:
I-Worm.BadtransII [KAV], Badtrans.B@mm [Norman], W32/Badtrans.B [Panda], WORM_BADTRANS.B [Trend], W32/Badtrans-B [Sophos], W32/Badtrans.B@mm [F-Secure], W32/BadTrans@MM [McAfee], Win32.Badtrans.29020 [CA], Worm/Badtrans.B [Vexira]
Systems Affected:
CVE References:

This worm arrives as an email with one of several attachment names and a combination of two appended extensions. It contains a set of bits that control its behavior:
001 Log every window text
002 Encrypt keylog
004 Send log file to one of its addresses
008 Send cached passwords
010 Shut down at specified time
020 Use copyname as registry name (else kernel32)
040 Use kernel32.exe as copyname
080 Use current filename as copypath (skips 100 check)
100 Copy to %system% (else copy to %windows%)

NOTE: If Norton AntiVirus detects this in an email message as W32.Badtrans@mm.enc (not as W32.Badtrans.B@mm), this is the detection for the MIME-encoded exploit in the body of the email, and it is harmless as long as the attachment has been deleted. We recommend that you delete messages detected as W32.Badtrans.B@mm.enc and notify the person who sent it to you. We also strongly recommend that you run a full system scan to make sure that no other infection exists.

For additional information on .enc detections, read the document What is an .enc detection?

When it is first executed, it copies itself to %System% or %Windows% as Kernel32.exe, based on the control bits. Then it registers itself as a service process (Windows 9x/Me only). It creates the key log file %System%\Cp_25389.nls and drops %System%\Kdll.dll which contains the key logging code.

NOTE: %Windows% and %System% are variables. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) or the \System folder (by default this is C:\Windows\System or C:\Winnt\System32) and copies itself to that location.

A timer is used to examine the currently open window once per second and to check for a window title that contains any of the following as the first three characters:
  • LOG
  • PAS
  • REM
  • CON
  • TER
  • NET

These texts form the start of the words LOGon, PASsword, REMote, CONnection, TERminal, NETwork. There are also Russian versions of these same words in the list. If any of these words are found, then the key logging is enabled for 60 seconds. Every 30 seconds, the log file and the cached passwords are sent to one of these addresses or some others which are currently not operational:
  • ZVDOHYIK@yahoo.com
  • udtzqccc@yahoo.com
  • DTCELACB@yahoo.com
  • I1MCH2TH@yahoo.com
  • WPADJQ12@yahoo.com
  • smr@eurosport.com
  • bgnd2@canada.com
  • muwripa@fairesuivre.com
  • eccles@ballsy.net
  • S_Mentis@mail-x-change.com
  • YJPFJTGZ@excite.com
  • JGQZCD@excite.com
  • XHZJ3@excite.com
  • OZUNYLRL@excite.com
  • tsnlqd@excite.com
  • cxkawog@krovatka.net
  • ssdn@myrealbox.com

After 20 seconds, the worm shuts down if the appropriate control bit is set.

If RAS support is present on the computer, then the worm waits for an active RAS connection. When such a connection is made, with a 33-percent chance, the worm searches for email addresses in *.ht* and *.asp in %Personal% and Internet Explorer %Cache%. If it finds addresses in these files, then it sends mail to those addresses using the victim's SMTP server. If this server is unavailable, the worm will choose from a list of its own. The attachment name will be one of the following:
  • Pics
  • images
  • New_Napster_Site
  • news_doc
  • YOU_are_FAT!
  • stuff
  • Card
  • Me_nude
  • Sorry_about_yesterday
  • info
  • docs
  • Humor
  • fun

In all cases, MAPI will also be used to find unread mail to which the worm will reply. The subject will be "Re:". In that case, the attachment name will be one of the following:
  • PICS
  • New_Napster_Site
  • CARD
  • Sorry_about_yesterday
  • DOCS
  • FUN

In all cases, the worm appends two extensions. The first is one of the following:
  • .doc
  • .mp3
  • .zip

The second extension that is appended to the file name is one of the following:
  • .pif
  • .scr

The resulting file name would look similar to CARD.doc.pif or NEWS_DOC.mp3.scr.

If SMTP information can be found on the computer, then it will be used for the From: field. Otherwise, the From: field will be one of these:
  • "Mary L. Adams" <mary@c-com.net>
  • "Monika Prado" <monika@telia.com>
  • "Support" <support@cyberramp.net>
  • " Admin" <admin@gte.net>
  • " Administrator" <administrator@border.net>
  • "JESSICA BENAVIDES" <jessica@aol.com>
  • "Joanna" <joanna@mail.utexas.edu>
  • "Mon S" <spiderroll@hotmail.com>
  • "Linda" <lgonzal@hotmail.com>
  • " Andy" <andy@hweb-media.com>
  • "Kelly Andersen" <Gravity49@aol.com>
  • "Tina" <tina0828@yahoo.com>
  • "Rita Tulliani" <powerpuff@videotron.ca>
  • " Anna" <aizzo@home.com>

Email messages use the malformed MIME exploit to allow the attachment to execute in Microsoft Outlook without prompting. For information on this, go to:


The worm writes email addresses to the %System%\Protocol.dll file to prevent multiple emails to the same person. Additionally, the underscore ( _ ) character is prepended to the sender's email address, which prevents replying to infected mails to warn the sender (for example, user@website.com becomes _user@website.com).

After sending the mail, the worm adds the value

Kernel32   kernel32.exe

to the registry key


This causes the worm to run the next time that you start Windows. This value can differ based on the control bits mentioned previously.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Peter Ferrie
Summary| Technical Details| Removal

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