Threat Description

Backdoor: W32/Agent.IFX


Category: Malware
Type: Backdoor
Platform: W32
Aliases: Trojan.Win32.Agent.aulk, Sus/Dropper-A (Sophos), Backdoor:Win32/Koutodoor.A (Microsoft), Generic Backdoor Trojan (McAfee)


A remote administration utility which bypasses normal security mechanisms to secretly control a program, computer or network.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

This malware installs a DLL file to the system that provides backdoor functionality. The malware also makes changes to the Internet Explorer (IE) web browser start page and attempts to connect to remote sites.


During installation, the malware creates these files:

  • %appdata%\Microsoft\Internet Explorer\Quick Launch\Internet Explorer.lnk - Creates a quicklaunch IE, opens
  • %favorites%\.url - Creates a "favorites" link in IE to the page
  • %windir%\system32\[RANDOM].dll
  • %windir%\system32\drivers\[RANDOM].sys
  • %windir%\system32\[RANDOM].bat

It also changes the IE start page to:

  • HK_USERS\[...]\Microsoft\Internet Explorer\Main Start Page = ""

When first executed, the malware will create the files listed above. It will then execute the batch file to delete itself.The DLL file and driver are also installed into the system. From then on, the DLL and driver will provide the backdoor functionality.The malware attempts to connect to:

  • www. buyaohenchang. cn/api.php?xxxxxxx
  • www. woyaochidongxi. com/update.php?xxxxx

The malware will launch itself by adding this entry into registry :

  • HKLM\System\CurrentControlSet\Services\[RANDOM] ImagePath = system32\drivers\[RANDOM].sys


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