Microsoft .doc exploit

[Kai Schaetzl]

Julian Field wrote on Sat, 20 May 2006 18:01:42 +0100:

> So 
> for a random filename and file content, you actually cannot say for 
> definite what will happen when a user tries to "run" a file. As far as I 
> am aware, Microsoft do not document the circumstances in which they use 
> the file's content and not its name.

What happens is the following:
- if the file suffix is known to the system (a suffix registered in HKR) it 
will open with the program associated with it
- if the file suffix is not known Windows will launch a dialog depending on 
the Windows version what to do with it 
- if the file suffix is not known, but is a Microsoft Office file Windows 
is able to detect that and will not offer that dialog but open it in the 
associated program
(that means changing a .doc file to .txt will *not* launch Word because 
that is a known file type associated to a text editor)

So, blocking .doc etc. files by suffix seems to be a failed effort since it 
doesn't seem to matter which (or if) extension they have. :-(

Kai

-- 
Kai Schätzl, Berlin, Germany
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