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[DR018] Quartz Composer / QuickTime 7 information leakage
From: David Remahl <vuln () remahl se>
Date: Thu, 12 May 2005 02:00:39 +0200

Hash: SHA1

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

    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


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.


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.


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.



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.


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.


Apple Computer
∙ 2005-05-10, 04:50 UTC: Confirmed receipt of problem report (did not confirm issue).
Version: GnuPG v1.4.1 (Darwin)

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