US-CERT Technical Cyber Security Alert TA07-334A -- Apple QuickTime RTSP Buffer Overflow

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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>

_________________________________________________________________

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

<http://www.us-cert.gov/cas/techalerts/TA07-334A.html>
_________________________________________________________________

Feedback can be directed to US-CERT Technical Staff. Please send
email to <cert@cert.org> with "TA07-334A Feedback VU#659761" in the
subject.
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Produced 2007 by US-CERT, a government organization.

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Revision History

November 30, 2007: Initial release
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