This policy setting allows administrators to add file types (determined by file extension) to the standard list of file types that InfoPath 2007 blocks users from attaching to forms.
If you enable this policy setting, you can specify file type extensions to block in addition to the standard list of prohibited file types in InfoPath 2007.
If you disable or do not configure this policy setting, users can attach any type of file to the form except potentially unsafe files that might contain viruses, such as .bat or .exe files. For the full list of file types that InfoPath 2007 disallows by default, see "Security Details" on this page: http://r.office.microsoft.com/r/rlidGroupPolicyFileAttachCtrl2?clid=en-us.
Prevent these file types from being added to forms
Example: '.ext', or '.ext, .ex1, .ex2, <...>'