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The canonical URI of this advisory is <http://remahl.se/david/vuln/ 
018/>.

This advisory concerns an as-yet unpatched problem in QuickTime 7 on  
Mac OS X 10.4. The reason for disclosure before a vendor patch is  
that another person realized the potential problem independently and  
posted a message about it to the public mailing list quartzcomposer- 
dev (hosted by Apple).

The suggested workaround is to disable the QuickTime browser plugin  
until a fix is available from the vendor.

/ Regards, David Remahl

DR018: Quartz Composer / QuickTime 7 information leakage
=================================

   Date of discovery: 2005-04-26
Date of publication: 2005-05-11
       Discovered by: David Remahl <david@remahl.se>
        Advisory URL: http://remahl.se/david/vuln/018/
                CVEs: n/a [as of this writing, the author is aware of  
no CVEs assigned to this vulnerability]
      Classification: information exposure; design error
             License: Public Domain

AFFECTED PRODUCTS
     Verified vulnerable:
         * Apple Mac OS X 10.4 (QuickTime 7)
     Verified safe:
         * Apple Mac OS X 10.3.9 (QuickTime 6.5, 7)
         * QuickTime for Windows

INTRODUCTION

Quartz Composer files are created with the Quartz Composer  
application included with the developer tools. The compositions (QTZ  
files) it creates can be used as screen savers, viewed as they are in  
the application or embedded as QT atoms in a .mov container. As such,  
they can be viewed in a wide-ranging array of environments, including  
a web browser, Keynote 2 and the Finder.

Compositions have access to a number of powerful tools (patches),  
each providing or acting-upon information, ultimately resulting in a  
graphic composition. The design assumption seems to be that these  
details should always be contained within the presentation. However,  
by combining patches that provide advanced system information with  
patches that load information from the Internet, a malicious .mov  
file (viewed for example by the QuickTime web plugin) can leak this  
information to an external host.

This issue has not been addressed by Apple yet, and because details  
of the potential exploit appeard in a public forum shortly after I  
had notified the vendor, a fix may still be some time away. A  
temporary work-around is disabling the QuickTime plugin and treating  
Quartz Composer files with suspicion.

IMPACT

The information that can be leaked by this method includes (but may  
not be limited to):
     •     local user name (long and short)
     •     computer name
     •     local IP
     •     OS / kernel version
     •     CPU / RAM / GPU configuration
     •     names (human-readable) of Bonjour services on the local  
network
     •     local or system time
     •     volume of audio input
     •     lists of images (including pdfs) matching arbitrary  
spotlight queries
     •     lists of images (including pdfs) in specific directories  
(relative to / or ~)
     •     the existence of image and movie files can indicate the  
existance of certain software packages

This information can be used for profiling of potential victims, for  
further use in attacks against the user's system or phising related  
social engineering.

DEMONSTRATION

A proof-of-concept in the form of a Quartz Composer composition  
embedded in a .mov  file is avaiilable at the following link. Please  
see that document for more information.

     http://remahl.se/david/vuln/018/demo.html

DETAILS

The basic attack works as follows:
     1.      A patch providing the information (for example the Host  
Info patch) is created (A)
     2.      The output of (A) is connected to a JavaScript patch  
which uses encodeURIComponent() to URI encode the string (B).
     3.      The output of (B) is connected to a String Printer which  
results in a URI, for example  (C)
     4.      The output of (C) is connected to the URL input  
connection of either the Image Downloader patch or the RSS Feed  
patch. (D)
     5.      The output of (D) must be used somehow, otherwise this  
part of the patch graph will not be used. Rendering the output (via a  
String to Image) to a 0-sized billboard is fine.
     6.      When the (D) patch is activated, it will access the URI  
(output of (C)), thus leaking the restricted information to an HTTP  
host of the attacker's choice.

VENDOR CONTACT

Apple Computer's  security team was contacted with information about  
the issue on 2005-05-06.  Following a discussion of this problem on  
the public quartzcomposer-dev mailinglist  (initiated by a third- 
party), the full details of the problems were released on May 11.

RESPONSE

Apple Computer
     •     2005-05-10, 04:50 UTC: Confirmed receipt of problem report  
(did not confirm issue).
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