Threat Descriptons



Category :


Type :


Aliases :

W32/Autorun-jl (Sophos), Generic.dx trojan (McAfee), WORM_AUTORUN.RC (Trend Micro), W32.SillyFDC (Symantec), Worm:Win32/Emold.C (Microsoft)


A standalone malicious program which uses computer or network resources to make complete copies of itself.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Worm.Win32.AutoRun.noi creates a copy of itself as the following:

  • C:\Program Files\Microsoft Common\wuauclt.exe

It creates the following registry key:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\explorer.exeDebugger = "%ProgramFiles%\Microsoft Common\wuauclt.exe

Note: The key is created for automatic execution when explorer.exe is launched.

It also drops two files into the root of available removable drives:

  • autorun.inf
  • system.exe

It then injects codes to explorer.exe.

The autorun.inf file is an autorun file of system.exe and contains the following strings:

  • [autorun]open=system.exeshellexecute=system.exeshell\Explore\command=system.exeshell\Open\command=system.exeshell=Explore

Worm.Win32.AutoRun.noi attempts to retrieve information from:


The worm uses rootkit stealth techniques to hide its presence on the infected machine, including deleting its own installation file once the installation has been completed.

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