[cap-talk] Windows Vista: security by admonition

[David Hopwood]

David Hopwood wrote:
> Karp, Alan H wrote:
>>David Hopwood wrote:
>>
>>>If any random user application can scribble over "trusted" 
>>>dialogs, it's not a trusted path, period. This needs to be 
>>>shouted from the rooftops, otherwise MS's marketing will win 
>>>out by default.
>>
>>It's a problem only if the click in the overlay window gets passed
>>through to the window underneath.  I don't believe that happens, but it
>>is Microsoft, so you never know.
> 
> # With UIPI enabled, the following shared USER resources are still shared
> # between processes at different privilege levels.
> #
> # - Desktop window, which actually owns the screen surface
> 
> So you can scribble anywhere on the screen, "above" other windows (by drawing
> on the DC returned by GetDC(NULL)) without needing an overlay window. Yes,
> this is a documented "feature" that is still intended to work on Vista:
> <http://blogs.msdn.com/nickkramer/archive/2006/04/07/571162.aspx>.

It appears that this has now been fixed, by displaying UIPI prompts on the
same desktop as used for the logon prompt; see the entry for May 3 at
<http://blogs.msdn.com/uac/>.

(Never let it be said that I'm not fair to Microsoft when they do actually
fix something -- even if my overall impression of their security efforts
with Vista is still that it's like rearranging deckchairs on the Titanic.)

> Also useful for viruses to capture a screen snapshot.

This hasn't been fixed, though.

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>