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F-Secure Malware Information Pages: Trojan-Proxy:W32/Xorpix.AR
[Summary] | [Disinfection] | [Detailed Description] | [Detection]

Name : Trojan-Proxy:W32/Xorpix.AR
Alias:Trojan-Proxy.Win32.Xorpix.ar
Size:18432
Type:Trojan-Proxy
Category:Malware
Platform:W32
Date of Discovery:May 30, 2007
Radar

Summary
Trojan-Proxy:W32/Xorpix.AR injects its code to the process WINLOGON.EXE. It then opens Internet Explorer and acts as a proxy server.
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Disinfection

Automatic Disinfection

Usually standalone malware (backdoors, worms, trojans, etc.) is automatically removed by F-Secure Anti-Virus (FSAV) starting from version 5.40. Malware files get automatically renamed by FSAV, so they can not be started any more. In some rare cases, when automatic disinfection is not possible, a user can select disinfection action by him/herself to make FSAV rename or delete an infected file. In some special cases, it is recommended to use specific disinfection tools provided by F-Secure. They can be downloaded from our ftp site:

ftp://ftp.f-secure.com/anti-virus/tools/

F-Secure Anti-Virus can be purchased from our web shop or from our authorized distributors. A trial version F-Secure Anti-Virus, limited to 30 days, can be downloaded from our website:

http://www.f-secure.com/download-purchase/

All the latest versions of FSAV can download anti-virus database updates automatically. However, these updates can be also downloaded and installed manually from our web or ftp sites:

http://www.f-secure.com/download-purchase/updates.shtml


Manual Disinfection

To manually disinfect standalone malware (backdoors, worms, trojans, etc.) it is usually enough to delete all infected files from a computer and to restart it. Active malware files are usually locked by operating system so different disinfection approaches are required for different operating systems.
Please note that manual disinfection is a risky process, so it is recommended only for advanced users.

If Windows 95, 98 and ME operating system is used, it is recommended to restart a computer from a bootable system diskette and to delete an infected file from the command prompt. For example, if a malicious file named ABC.EXE is located in the Windows folder, it is usually enough to type the following command at the command prompt:

DEL C:\WINDOWS\ABC.EXE

and to press Enter. After that the infected file will be gone. If Windows NT, 2000 or XP is used, a malicious file has to be renamed with a different extension (for example .VIR) and then a system has to be restarted. After restarting, a renamed malicious file will no longer be active and it can be easy to delete manually.


Malware Disinfection Tools

F-Secure provides disinfection tools for certain malware. These tools can be downloaded from this web page:

http://www.f-secure.com/download-purchase/tools.shtml

ftp://ftp.f-secure.com/anti-virus/tools/


Windows System Restore Issues

If Windows ME or XP is used, it is recommended to disable System Restore feature of these operating systems to prevent a computer from re-infection by an already removed malware. The fact is that System Restore feature of these operating systems might save an infected file into the special folder and copies it back to a hard drive it every time it has been renamed or deleted by F-Secure Anti-Virus or by a user. Instructions on how to disable System Restore features are here:

Windows ME:
http://www.f-secure.com/v-descs/sfc_dis.shtml

Windows XP:
http://www.f-secure.com/v-descs/sfc_dis1.shtml

It is recommended to re-enable System Restore after disinfection in order to restore stable system configuration, if any crash or incompatibility issue occurs in the future.

Failed Disinfection

In some cases, F-Secure Anti-Virus might not disinfect a system automatically. In this case, please visit our Support pages:

http://support.f-secure.com/enu/home/virusproblem/howtoclean/
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Detailed Description
Upon execution, the file detected as Trojan-Proxy.Win32.Xorpix.ar will drop DLL files with the following filenames:

  • bot.dll
  • dn.dll
  • partneship.dll

It will then create the following registry entries:

  • HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\%dll_name%reg
    DllName "C:\Documents and Settings\All Users\Documents\Settings\%dll_name%.dll"
    Startup "%dll_name%reg"
    Impersonate dword:00000001
    Asynchronous dword:00000001

Note: %dll_name% represents the filename of the dropped DLL.

Here are the registry entries:

  • HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\partnershipreg
    DllName "C:\Documents and Settings\All Users\Documents\Settings\partnership.dll"
    Startup "partnershipreg"
    Impersonate dword:00000001
    Asynchronous dword:00000001
  • HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\bnreg
    DllName "C:\Documents and Settings\All Users\Documents\Settings\bn.dll"
    Startup "bnreg"
    Impersonate dword:00000001
    Asynchronous dword:00000001
  • HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\botreg
    DllName "C:\Documents and Settings\All Users\Documents\Settings\bot.dll"
    Startup "botreg"
    Impersonate dword:00000001
  • Asynchronous dword:00000001

Xorpix.AR will then inject its code to the process Winlogon.exe. It then opens an instance of Internet Explorer and uses a random port to act as a proxy server.
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Detection

F-Secure Anti-Virus detects this malware with the following updates:

[FSAV_Database_Version]

Version = 2007-06-18_05.
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F-Secure Corporation

Last Modified: June 19, 2007