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          National Cyber Alert System
   Technical Cyber Security Alert TA07-334A


Apple QuickTime RTSP Buffer Overflow

   Original release date: November 30, 2007
   Last revised: --
   Source: US-CERT

Systems Affected

   A buffer overflow in Apple QuickTime affects:
     * Apple QuickTime for Windows
     * Apple QuickTime for Apple Mac OS X

Overview

   Apple QuickTime contains a buffer overflow vulnerability in the way
   QuickTime processes Real Time Streaming Protocol (RTSP) streams.
   Exploitation of this vulnerability could allow an attacker to execute
   arbitrary code.

I. Description

   Apple QuickTime contains a stack buffer overflow vulnerability in the
   way QuickTime handles the RTSP Content-Type header. Most versions of
   QuickTime prior to and including 7.3 running on all supported Apple
   Mac OS X and Microsoft Windows platforms are vulnerable. Since
   QuickTime is a component of Apple iTunes, iTunes installations are
   also affected by this vulnerability.

   An attacker could exploit this vulnerability by convincing a user to
   access a specially crafted HTML document such as a web page or email
   message. The HTML document could use a variety of techniques to cause
   QuickTime to load a specially crafted RTSP stream. Common web
   browsers, including Microsoft Internet Explorer, Mozilla Firefox, and
   Apple Safari can be used to pass RTSP streams to QuickTime, exploit
   the vulnerability, and execute arbitrary code.

   Exploit code for this vulnerability was first posted publicly on
   November 25, 2007.

II. Impact

   This vulnerability could allow a remote, unauthenticated attacker to
   execute arbitrary code or commands and cause a denial-of-service
   condition.

III. Solution

   As of November 30, 2007, a QuickTime update for this vulnerability is
   not available. To block attack vectors, consider the following
   workarounds.

Block the rtsp:// protocol

   Using a proxy or firewall capable of recognizing and blocking RTSP
   traffic can mitigate this vulnerability. Known public exploit code for
   this vulnerability uses the default RTSP port 554/tcp, however RTSP
   can use a variety of ports.

Disable file association for QuickTime files

   Disable the file association for QuickTime file types. This can be
   accomplished by deleting the following registry keys:
   HKEY_CLASSES_ROOT\QuickTime.*

   This will remove the association for approximately 32 file types that
   are configured to open with QuickTime Player.

Disable the QuickTime ActiveX controls in Internet Explorer

   The QuickTime ActiveX controls can be disabled in Internet Explorer by
   setting the kill bit for the following CLSIDs:
       {02BF25D5-8C17-4B23-BC80-D3488ABDDC6B}
       {4063BE15-3B08-470D-A0D5-B37161CFFD69}

   More information about how to set the kill bit is available in
   Microsoft Knolwedgebase Article 240797. Alternatively, the following
   text can be saved as a .REG file and imported to set the kill bit for
   these controls:
   
   Windows Registry Editor Version 5.00
   
       [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX
       Compatibility\{02BF25D5-8C17-4B23-BC80-D3488ABDDC6B}]
       "Compatibility Flags"=dword:00000400
       
       [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX
       Compatibility\{4063BE15-3B08-470D-A0D5-B37161CFFD69}]
       "Compatibility Flags"=dword:00000400

Disable the QuickTime plug-in for Mozilla-based browsers

   Users of Mozilla-based browsers, such as Firefox can disable the
   QuickTime plugin, as specified in the PluginDoc article Uninstalling
   Plugins.

Disable JavaScript

   For instructions on how to disable JavaScript, please refer to the
   Securing Your Web Browser document. This can help prevent some attack
   techniques that use the QuickTime plug-in or ActiveX control.

Secure your web browser

   To help mitigate these and other vulnerabilities that can be exploited
   via a web browser, refer to Securing Your Web Browser.

Do not access QuickTime files from untrusted sources

   Do not open QuickTime files from any untrusted sources, including
   unsolicited files or links received in email, instant messages, web
   forums, or internet relay chat (IRC) channels.


References

 * US-CERT Vulnerability Note VU#659761 - <http://www.kb.cert.org/vuls/id/659761>

 * Securing Your Web Browser - <http://www.us-cert.gov/reading_room/securing_browser/>

 * Mozilla Uninstalling Plugins - <http://plugindoc.mozdev.org/faqs/uninstall.html>

 * How to stop an ActiveX control from running in Internet Explorer - <http://support.microsoft.com/kb/240797>

 * IETF RFC 2326 Real Time Streaming Protocol - <http://tools.ietf.org/html/rfc2326>
  

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   The most recent version of this document can be found at:

     <http://www.us-cert.gov/cas/techalerts/TA07-334A.html>
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   Feedback can be directed to US-CERT Technical Staff. Please send
   email to <cert@cert.org> with "TA07-334A Feedback VU#659761" in the
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   Produced 2007 by US-CERT, a government organization.

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     <http://www.us-cert.gov/legal.html>
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Revision History

   November 30, 2007: Initial release
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