RE: Citrix application breakout - take care of Microsoft calculator

["Robert S. Slifkin" <rob () SLIFKIN NET>]

Yes, that can be particularly dangerous.  From there you can launch the
explorer shell to get a full desktop and everything with System
privileges.   


____________________________________
Robert S. Slifkin
Email: Rob () slifkin net
Phone: 203.962.3878

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Bill Stout
Sent: Monday, March 17, 2008 12:32 AM
To: pen-test () securityfocus com
Subject: Re: Citrix application breakout - take care of Microsoft
calculator


Or this command string, which will pop up a second command window, but
with 'system' privileges.
 
c:\> at 21:00 /interactive %systemroot%\system32\cmd.exe

 
Bill Stout


----- Original Message ----
> From: "infolookup () gmail com" <infolookup () gmail com>
> To: Erik Soosalu <eriks () nationalfastfreight com>; 
> listbounce () securityfocus com; pen-test () securityfocus com
> Sent: Wednesday, March 12, 2008 4:46:34 AM
> Subject: Re: Citrix application breakout - take care of Microsoft 
> calculator
>
> A discussion of this nature started a while back where someone noted 
> that you could if giving regular user rights on a Citrix terminal 
> still browse the network for shares.
>
> Right click your desktop, select new shortcut and browse to 
> system32/cmd.exe get a list of host name and available shares.
>
> Then open up MS word and create a link to the share, click on it then 
> you are browsing the share, or network place in question, in some 
> cases you can even browse the underlining Citrix server that you are 
> connected too, or create a folder and copy anything to it.
> Sent from my Verizon Wireless BlackBerry
>
> -----Original Message-----
> From: "Erik Soosalu" 
>
> Date: Mon, 10 Mar 2008 12:50:40
> To:
> Subject: RE: Citrix application breakout - take care of Microsoft 
> calculator
>
>
> Once you're in Notepad, File->Open, browse to Windows/system32, find 
> cmd.exe right click and open and you have a command prompt on the box.

> Of course, your could specify any UNC and get a file to load from 
> wherever you want. Not sure what the actual run permissions would
be....
> Erik
>
>
>
> ________________________________
>
> From: listbounce () securityfocus com on behalf of Stefan Gora
> Sent: Fri 3/7/2008 6:13 AM
> To: pen-test () securityfocus com
> Subject: Citrix application breakout - take care of Microsoft 
> calculator
>
>
>
> Dear all,
>
> I'm not shure if the following issue is already known or exciting, 
> nevertheless the following attack vector found during a penetration 
> test might be interesting:
>
> A customer has built a Citrix environment for a partner company to 
> provide access to a specific application. This application was 
> intended to be the only application accessible for this partner. It 
> was possible to get a remote task manager with CRTL-F3, but no other 
> way of interacting with the Citrix Server (e.g. through printing or
so).
> Unfortunately they have integrated Microsoft's calculator into the 
> application. A bad idea - guess why ;-).
>
> Using the calculator you are able to do funny stuff: Open the 
> calculator and click "info". Klick on the licence agreement and here 
> you go, you have got an editor. With this you can use "open file" and 
> browse the server, find for example Word and rightclick on "Open" - 
> Word is running, and all other applications which you like as well ...
>
> I think this can easily be fixed using more restrictive file 
> permissions, but I thought maybe some of you might find this 
> information useful.
>
> Stefan
>
> --
> --------------------------------------------------------
> Identity Management Symposium 22.-23.04.2008 KA/Ettlingen 
> http://www.identity-management-symposium.de
>
> --------------------------------------------------------
>
> Stefan Gora
> Security Consultant
>
> Secorvo Security Consulting GmbH
> Ettlinger Strasse 12-14, D-76137 Karlsruhe Tel. +49 721 255171-302, 
> Fax +49 721 255171-100 stefan.gora () secorvo de, http://www.secorvo.de
> PGP: 5EAD 34FE F3C1 0FEB 058F 4DD0 E6B3 FF4A
>
> Mannheim HRB 108319, Geschaeftsfuehrer: Dirk Fox
>
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