Funner is a MSN worm that spreads by sending itself to the contacts listed in Microsoft's Windows Messenger.
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.
When executed, Funner will copy itself to the WINDOWS directory under the name rundll32.dll and alter registry entries to ensure the worm is started. It will also copy itself under WINDOWS SYSTEM directory as
explorer.exe IEXPLORE.EXE userinit32.exe
The following registry keys are altered to ensure the worm runs upon next reboot
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run "MMSystem" "c:\winnt\rundll32.exe "c:\winnt\system32\mmsystem.dll"", RunDll32" HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run "MMSystem" "c:\winnt\rundll32.exe "c:\winnt\system32\mmsystem.dll"", RunDll32" HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon "Userinit" "C:\WINNT\system32\userinit32.exe,"
Funner also overwrites the local hosts file with a file containing various URLs.
NOTE! There is Windows system DLL named rundll32.dll under WINDOWS SYSTEM directory. This DLL is part of Microsoft Windows operating system.