Microsoft Windows keybd_event validation vulnerability

[Frederic Charpentier]

Hi list,
I haven't seen any information about this new local exploit for
Microsoft Windows :

http://www.haxorcitos.com/MSRC-6005bgs-EN.txt

Description from Haxorcitos :

As is Known, with the current Microsoft Security Model, applications
that share the destkop
are able to send messages between them.
Every Desktop application is able to obtain the handle of every process
executed in the same desktop.

This feature and the possibility of any application to emulate a virtual
keyboard by sending key strokes,
allows every process to send messages and keys as if there were an
interactive user.


Bests regards,

--
Frédéric Charpentier - Xmco Partners
Security Consultant / Pentest
web : http://www.xmcopartners.com

[Ansgar -59cobalt- Wiechers]

On 2005-09-06 Frederic Charpentier wrote:
> I haven't seen any information about this new local exploit for
> Microsoft Windows :
>
> http://www.haxorcitos.com/MSRC-6005bgs-EN.txt
>
> Description from Haxorcitos :
>
> As is Known, with the current Microsoft Security Model, applications
> that share the destkop are able to send messages between them.
> Every Desktop application is able to obtain the handle of every
> process executed in the same desktop.
>
> This feature and the possibility of any application to emulate a
> virtual keyboard by sending key strokes, allows every process to send
> messages and keys as if there were an interactive user.

This has been known for years and is the exact reason why Microsoft
recommends that any service running with elevated privileges should
*not* be run interactively [1].

This flaw allows for shatter attacks [2,3] and we have used it in [4] to
attack personal firewalls.

[1] http://support.microsoft.com/default.aspx?scid=kb;en-us;327618
[2] http://security.tombom.co.uk/shatter.html
[3] http://security.tombom.co.uk/moreshatter.html
[4] http://copton.net/vortraege/pfw/index.html

Regards
Ansgar Wiechers
--
"Another option [for defragmentation] is to back up your important files,
erase the hard disk, then reinstall Mac OS X and your backed up files."
--http://docs.info.apple.com/article.html?artnum=25668

[galacticjello@eforu.com]

That's because it's not an exploit. If you have a program that can run a shell, and it is running under a privileged account, guess what? The shell will run under the same privileged account.

This "exploit" is a "by design".

The writers suggest that if you are logged in to a privileged account, then do a "run as" to run another app under a non-privliged account, you can script explorer to run a shell as your original privileged account (which you could just do anyway by dropp
ing to a command prompt).

They must be dragging the bottom of the barrel for "exploits".