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F-Secure Malware Information Pages: Trojan:W32/Pakes.CSG

[Summary] | [Detailed Description]

Name : Trojan:W32/Pakes.CSG
Alias:FraudTool.Win32.WinFixer.e, Trojan.Win32.Pakes.csg
Type:Trojan
Category:Malware
Platform:W32
Radar

Summary
Trojan:W32/Pakes.CSG attempts to get "rogueware" installed on the victim's computer by claiming the computer is infected by spyware.

It also makes changes to the system registry and posts information about the computer to a remote server.
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Detailed Description
Pakes.CSG

Once executed the trojan copies itself to the following location:

  • %windir%\system32\ctfmona.exe

It drops the following two files, a desktop wallpaper and a screensaver:

  • %windir%\system32\ctfmonb.bmp
  • %windir%\system32\blackster.scr

The ctfmonb.bmp file is set as the desktop wallpaper to warn the user of a non-existent spyware infection.



The file called blackster.scr is set as the system's screensaver. Once it activates, a legion of bugs appear to eat away the desktop. The screensaver appears to not have been made by authors of the trojan. The original version is available on the Internet as freeware.

Therefore having a similar screensaver alone does not mean you have a trojan on your computer.



To enable its execution on start-up and to change the wallpaper and screensaver, the trojan makes several changes to the system registry. Trojan:W32/Pakes.CSG also disables System Restore with a registry modification.

The following is a list of the registry changes made by Pakes.CSG:

  • HKLM\Software\Microsoft\Software Notifier
    InstallationID = 30ca1f71-3146-4d7b-a35f-3736e1cd05bd
  • HKCU\Control Panel\Colors
    Background = 0 0 255
  • HKCU\Control Panel\Desktop
    WallpaperStyle = 0 [Wallpaper Changed]
  • HKCU\Control Panel\Desktop
    TileWallpaper = 0
  • HKCU\Control Panel\Desktop
    Wallpaper = C:\WINDOWS\system32\ctfmonb.bmp [Wallpaper Changed]
  • HKCU\Control Panel\Desktop
    OriginalWallpaper = C:\WINDOWS\system32\ctfmonb.bmp
  • HKCU\Control Panel\Desktop
    ConvertedWallpaper = C:\WINDOWS\system32\ctfmonb.bmp
  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run
    ctfmona = C:\WINDOWS\system32\ctfmona.exe [Launchpoint: Run]
  • HKLM\System\CurrentControlSet\Services\srservice
    Start = 00000002
  • HKLM\System\CurrentControlSet\Services\sr
    Start = 00000000
  • HKLM\System\CurrentControlSet\Services\sr
    ImagePath = system32\DRIVERS\sr.sys [Launchpoint: Service]
  • HKLM\Software\Microsoft\Windows NT\CurrentVersion\SystemRestore
    DisableSR = 00000000 [System Restore Disabled]
  • HKCU\Control Panel\Desktop
    SCRNSAVE.EXE = C:\WINDOWS\system32\blackster.scr

Once running the trojan posts information to the following location:

  • http://www.winifixer.com/log2.php

The information sent by the trojan includes hardware and Operating System information, installed software, and currently running processes.

The trojan also attempts to connect to the following location:

  • http://windowsupdate.microsoft.com/

Connecting to Windows Update tests if the computer has a working Internet connection. The trojan then attempts to download a file from:

  • http://winifixer.com/banner2/1208441289/[Removed]/[Removed].gif

Rogue Antispyware

The goal of this trojan is to install and push the sale of a rogue application. Rogue applications produce fraudulent scan results and use affiliate programs to market themselves. Trojans such as Pakes.CSG are designed and used by unscrupulous affiliates.

More details are available from the Rogue antispyware description.
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F-Secure Corporation

Last Modified: April 24, 2008