Internet Explorer Processes

This policy setting determines whether Internet Explorer MIME sniffing will prevent promotion of a file of one type to a more dangerous file type.

If you enable this policy setting, MIME sniffing will never promote a file of one type to a more dangerous file type.

If you disable this policy setting, Internet Explorer processes will allow a MIME sniff promoting a file of one type to a more dangerous file type.

If you do not configure this policy setting, MIME sniffing will never promote a file of one type to a more dangerous file type.

Supported on: At least Internet Explorer 6.0 in Windows XP with Service Pack 2 or Windows Server 2003 with Service Pack 1

Enable policy:
Registry PathValue NameValue TypeValue
Software\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFING(Reserved)REG_SZ1
Software\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFINGexplorer.exeREG_SZ1
Software\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFINGiexplore.exeREG_SZ1
Disable Policy:
Registry HiveRegistry PathValue NameValue TypeValue
HKEY_LOCAL_MACHINE or HKEY_CURRENT_USERSoftware\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFING(Reserved)REG_SZ0
HKEY_LOCAL_MACHINE or HKEY_CURRENT_USERSoftware\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFINGexplorer.exeREG_SZ0
HKEY_LOCAL_MACHINE or HKEY_CURRENT_USERSoftware\Policies\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_MIME_SNIFFINGiexplore.exeREG_SZ0

inetres.admx

Administrative Templates (Computers)

Administrative Templates (Users)