Apple QuickTime RTSP Buffer Overflow

A buffer overflow in Apple QuickTime affects:

• Apple QuickTime for Windows
• Apple QuickTime for Apple Mac OS X

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.

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.

Impact

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

Solution

Apple has released QuickTime 7.3.1 to address this issue. Until updates can be applied, the below workarounds may prevent this vulnerability from being exploited.

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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Revision History

• November 30, 2007: Initial release