Threat description


Category: Malware
Type: Worm
Platform: W32
Aliases: Antinny, W32.HLLW.Antinny


This worm will spread though the P2P network of the Japanese software Winny P2P. The file length is 651264.


Automatic action

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


More information on scanning and removal options available in your F-Secure product can be found in the Help Center.

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

When the worm is executed it will display a fake error Window with Japanese text.

The worm incorporates DLLs within its body, with the purpose of handling LHA and ZIP compressed files. Those DLLs amount for most of the worm's length.

The DLLs will be copied to the Windows' system folder. Their names and lengths follow:

UNLHA32.DLL, 254.464 bytes  zip32.dll,   135.168 bytes  ZIP32J.DLL,   61.440 bytes   

all of those components are harmless by themselves.

The worm copies itself to the Windows' system folder, the full path of the file is:


and an entry in the Windows' Registry is added, aiming at having the worm start when Windows does.

"ara-key" = %WinSysDir%\ny.exe -StartUp   

It will then copy itself again, with the same name "ny.exe", to the user's default folder for temporary files.

The worm will attempt to find the Winny P2P software by searching the system for the application's main executable "Winny.exe", once found it will copy itself to the folder designated by the user as the one containing shared content. This will make the worm available for download to other users of the P2P network.


Detection in F-Secure Anti-Virus was published on August 18th, 2003 in update:

Detection Type: PC
Database: 2003-08-18_02

Technical Details:Ero Carrera, 26th of September, 2003


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