Threat description




Xombe trojan downloader was sent as an e-mail attachment to a large amount of people on 9th of January 2004. When run, the trojan downloader connects to Internet and downloads and activates another trojan on a victim's computer. UPDATE ON 10TH OF JANUARY 2003 The site used by this trojan (gamemaniacs.org) has now been disabled and this trojan won't be able to function any more.


Automatic action

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Technical Details

Xombe trojan downloader was sent to a large amount of people in the e-mail that looks like that:

  From:  windowsupdate@microsoft.com  Subject:  Windows XP Service Pack 1 (Express) - Critical Update.  Window Update has determined that you are running a beta version  of Windows XP Service Pack 1 (SP1).  To help improve the  stability of your computer, Microsoft recommends that you remove  the beta version of Windows XP SP1 and re-install Windows XP  SP1.  If you cannot remove the beta version, you should still  reinstall Windows XP SP1.  Windows XP SP1 provides the latest security, reliability, and  performance updates to the Windows XP family of operating  systems. Windows XP SP1 is designed to ensure Windows XP  platform compatibility with newly released software and  hardware, and includes updates to resolve issues discovered by  customers or by Microsoft's internal testing team.  The maximum download size is approximately 3 MB, however the  size of the download and time required may be less for computers  that have had updates previously installed.  To minimize the download time needed for installation, setup  will only download those files which are required to bring your  computer up to date.  Windows XP SP1 includes Internet Explorer 6  SP1.  Anti-virus software programs may interfere with the  installation of Windows XP SP1.  Please disable anti-virus  software while installing the service pack.  Just run the file winxp_sp1.exe in attach and make sure to  restart your PC after installation will be completed.  (c) 2004 Microsoft Corporation. All rights reserved. Terms of  Use Privacy Statement  Attachment:  winxp_sp1.exe   

When the trojan downloader is run by a user, it connects to Internet and downloads another trojan.

Trojan components

The trojan consists of three components:


This file is the first-stage downloader that comes in email. The only purpose of this program is to fetch the main component of the trojan and plant in on the target system.


This is the main component of the trojan. It is a general-purpose downloader application that is controlled through a certain web page. It can fetch arbitrary files from the Internet and install them on the infected system.

msvchost.exe is installed to the System Directory on the infected computer and added to the registry as [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\mssvc] When the trojan was first intercepted the website instructed the clients to download a DLL file.


http_f.dll is an HTTP client which is apparently used to perform a Distibuted Denial-of-Service attack on a website that hosts forums. This file is also dropped to the System Directory, just like the main component.

Description Created: 2006-01-01 08:49:18.0

Description Last Modified: 2006-01-01 00:00:00.0

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