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CSIRTUK ADVISORY -3543 - Apple - Apple QuickTime RTSP Response message Reason-Phrase buffer overflow vulnerability
CSIRTUK ADVISORY - 3543 dated 14.01.08 time 14:45
Centre for the Protection of National Infrastructure (CPNI)
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Apple - Apple QuickTime RTSP Response message Reason-Phrase buffer
Vulnerability Note VU#112179
Apple QuickTime RTSP Response message Reason-Phrase buffer overflow
Apple QuickTime contains a buffer overflow vulnerability that may allow
a remote, unauthenticated attacker to cause a denial-of-service
condition and possibly execute arbitrary code.
Real Time Streaming Protocol (RTSP) is a protocol that is used by
streaming media systems. Apple QuickTime Streaming Server and QuickTime
Player both support RTSP.
Apple QuickTime contains a buffer overflow vulnerability in the way
QuickTime handles RTSP response messages. For some RTSP Status-Codes,
QuickTime displays the Reason-Phrase (see RFC 2326). When attempting to
display a specially crafted Reason-Phrase, QuickTime Player crashes at a
memory location that can be conrtrolled by an attacker.
This vulnerability may be exploited by convincing a user to connect to a
specially crafted RTSP stream. Note that QuickTime is a component of
Apple iTunes, therefore iTunes installations are also affected by this
vulnerability. Apple Mac OS X and Microsoft Windows versions of
QuickTime are affected.
We are aware of publicly available proof-of-concept code for this
By convincing a user to connect to a specially crafted RTSP stream, a
remote attacker may be able to cause a denial of service or execute
arbitrary code on a vulnerable system. An attacker can use various types
of web page content, including a QuickTime Media Link file, to cause a
user to load an RTSP stream.
We are currently unaware of a practical solution to this problem.
Until updates are available, uninstalling QuickTime will mitigate this
vulnerability. Note that uninstalling QuickTime will make applications
that rely on QuickTime (such as iTunes) fail to run or run with limited
Block the rtsp:// protocol
Blocking the RTSP protocol with proxy or firewall rules may help
mitigate this vulnerability.
Blocking outbound access to 554/tcp and 6970-6999/udp may partially
mitigate this vulnerability. Since RTSP may use a variety of port
numbers, blocking the protocol based on a particular port may not be
Content-filtering, proxy servers and application firewalls may also be
used to block the RTSP protocol.
Secure your web browser
Follow the guidelines described in the Securing Your Web Browser
document. These guidelines include several mitigations against this
vulnerability, such as disabling downloads from untrusted sites in
Internet Explorer on Microsoft Windows systems and disabling the option
to Open "safe" files after downloading in Safari on Apple Mac systems.
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:
More information about how to set the kill bit is available in Microsoft
Support Document 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
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, or by using the NoScript plugin.
Disable the RTSP protocol handler
Mac OS X users can disable the RTSP protocol handler by editing the
~/Library/Preferences/com.apple.LaunchServices.plist file with Property
List Editor. Change the LSHandlerRoleAll value associated with the rtsp
LSHanlderURLScheme to something other than com.apple.quicktimeplayer.
This process can be simplified by using an application such as
RCDefaultApp. Microsoft Windows users should not need to make any
changes, as QuickTime does not appear to register itself as the handler
for the RTSP protocol on Windows systems.
Disable file association for QuickTime files
Disable the file association for QuickTime file types to help prevent
windows applications from using Apple QuickTime to open QuickTime files.
This can be accomplished by deleting the following registry keys:
This will remove the association for approximately 32 file types that
are configured to open with the QuickTime Player software.
Disable QuickTime as the RTSP protocol handler on OS X
To disable the RTSP registered protocol handler in OS X open
~/Library/Preferences/com.apple.LaunchServices.plist and look through a
hundred or more entries to find RTSP and change it to something else.
Securing Your Web Browser document. This can help prevent some attack
techniques that use the QuickTime plug-in or ActiveX control.
Do not access QuickTime files from untrusted sources
Attackers may host malicious QuickTime files on web sites. In order to
convince users to visit their sites, those attackers often use a variety
of techniques to create misleading links including URL encoding, IP
address variations, long URLs, and intentional misspellings. Do not
click on unsolicited links received in email, instant messages, web
forums, or internet relay chat (IRC) channels. Type URLs directly into
the browser to avoid these misleading links. While these are generally
good security practices, following these behaviors will not prevent
exploitation of this vulnerability in all cases, particularly if a
trusted site has been compromised or allows cross-site scripting.
Vendor Status Date Updated
Apple Computer, Inc. Vulnerable 10-Jan-2008
This vulnerability was disclosed by Luigi Auriemma.
This document was written by Ryan Giobbi, Chris Taschner, Will Dorman
and Art Manion.
Date Public 10/01/2008
Date First Published 10/01/2008 18:08:09
Date Last Updated 10/01/2008
Document Revision 23
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