Message-ID: <FB24803D1DF2A34FA59FC157B77C970503AD3D0C@idserv04.idef.com>
From: idlabs-advisories at idefense.com (idlabs-advisories@...fense.com)
Subject: iDEFENSE Security Advisory 12.21.04: Multiple
	Vendor Xine version
	0.99.2 PNM Handler Negative Read Length Heap Overflow Vulnerability

Multiple Vendor Xine version 0.99.2 PNM Handler Negative Read Length 
Heap Overflow Vulnerability

iDEFENSE Security Advisory 12.21.04
www.idefense.com/application/poi/display?id=177&type=vulnerabilities
December 21, 2004

I. BACKGROUND

Xine is a multimedia player which runs on multiple platforms.
More information is available at:
   
   http://xinehq.de/

II. DESCRIPTION

Remote exploitation of a buffer overflow in version 0.99.2 of xine could
allow execution of arbitrary code.

The vulnerability specifically exists in the RMF_TAG, DATA_TAG, 
PROP_TAG, MDPR_TAG and CONT_TAG handling code of the pnm_get_chunk() 
function. These tags are all handled by the same code. The code does not

perform correct checking on the chunk size before reading data in. If 
the size given is less than the PREAMBLE_SIZE, a negative length read is

made into a fixed length buffer. Because the read length parameter is an

unsigned value, the negative length is interpreted as a very large 
length, allowing a buffer overflow to occur.

III. ANALYSIS

Exploitation of this vulnerability allows execution of arbitrary code 
with the privileges of the targeted user.

In order to exploit this vulnerability, an attacker would have to 
convince the targeted user to open a connection to a malicious PNM 
server with xine, using a pnm://address/ URL. Depending on configuration

options, this may be exploitable simply by clicking on a link, or it may

require the user to launch the application, specifically requesting the 
malicious content.

IV. DETECTION

iDEFENSE Labs has confirmed the existence of this vulnerability in xine 
version 0.99.2. It is suspected that earlier versions of xine also 
contain this vulnerability.

This vulnerability also affects MPlayer prior to MPlayer 1.0pre5try2.

V. WORKAROUND

iDEFENSE is currently unaware of any effective workarounds for this 
issue.

VI. VENDOR RESPONSE

xine-lib 1-rc8 was released to address this vulnerability and is
available for download at:

   http://xinehq.de/index.php/releases
   
An xine patch for this vulnerability is available at:

 
http://cvs.sourceforge.net/viewcvs.py/xine/xine-lib/src/input/pnm.c?r1=1
.20&r2=1.21
   
An MPlayer patch for this vulnerability is available at:

   http://www.mplayerhq.hu/MPlayer/patches/pnm_fix_20041215.diff

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2004-1188 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

12/10/2004  Initial vendor notification
12/11/2004  Initial vendor response
12/21/2004  Public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp

X. LEGAL NOTICES

Copyright (c) 2004 iDEFENSE, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice@...fense.com for permission.

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
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.

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