AOL Nullsoft Winamp Ultravox 'ultravox-max-msg' Header Heap Overflow
Vulnerability

iDefense Security Advisory 10.25.06
http://www.idefense.com/intelligence/vulnerabilities/
Oct 25, 2006

I. BACKGROUND

Ultravox is a streaming media technology developed by AOL for delivering
and publishing streaming media such as music files. The Winamp media
player has support for this protocol. More information about Winamp is
available at the following site:

    http://www.winamp.com

II. DESCRIPTION

Remote exploitation of a heap-based buffer overflow vulnerability in the
Ultravox protocol handler of AOL Corp.'s Nullsoft Winamp media player
could allow an attacker to execute arbitrary code in the context of the
currently logged in user.

Due to an error in the handling of the 'ultravox-max-msg' header, it is
possible for a malicious server to cause the Winamp client to allocate a
very small amount of space and then try fill it with a large amount of
server supplied date, potentially overwriting values which will lead to
code execution.

III. ANALYSIS

Successful exploitation of this vulnerability would allow a remote
attacker to execute code in the context of the user who started Winamp.
In order to exploit this vulnerability, the attacker would need to cause
or convince the intended victim to connect to a malicious server. This
could be accomplished by embedding a link in a web page to a playlist
file, a 'shout:' URI or a 'uvox:' URI, which are automatically by Winamp
from Internet Explorer. Alternatively, one of these items could be
placed in a playlist file. The attacker would have no way to force the
user to open the content they have supplied.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in version
5.24 and 5.3 of Nullsoft Winamp. Previous versions also may be affected.

V. WORKAROUND

iDefense is currently unaware of any effective workarounds for this
vulnerability.

VI. VENDOR RESPONSE

Nullsoft has released version 5.31 of Winamp to address this problem.

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

10/19/2006  Initial vendor notification
10/25/2006  Initial vendor response
10/25/2006  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
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or consequential loss or damage arising from use of, or reliance on,
this information.