Winamp m3u Parsing Stack Overflow Vulnerability iDefense Security Advisory 02.01.06 http://www.idefense.com/intelligence/vulnerabilities/display.php?id=377 February 1, 2006 I. BACKGROUND Winamp is a popular media player for Windows which supports many audio/video file formats. More information can be obtained from the vendors site at: http://winamp.com/player/ II. DESCRIPTION It has been found that a specially crafted m3u or pls file can overwrite a stack based buffer allowing for remote code execution. Example m3U file format: #EXTM3U #EXTINF:,VULN AAAA[...]AA Example pls file to trigger exploit: [playlist] numberofentries=1 File1=\01 01AAA[...]AAA This vulnerability is specific to the 5.11 version of Winamp and does not affect previous versions. III. ANALYSIS When Winamp is installed it registers the m3u extension so that such files will automatically open in Winamp. This exploit can be triggered by clicking on a link in a webpage, or from the use of malicious javascript. Exploitation is straight forward, using a long full path. This path can be either a filename or the UNC name for a fileshare, which does not have to exist. Public exploit code has been independently released for this vulnerability (http://www.spyinstructors.com). IV. DETECTION This exploit was tested with version 5.11 of Winamp. Previous versions were tested and found to not be exploitable. V. WORKAROUND Removing the file associations for the m3u and pls file extension may mitigate the risk of exploitation. VI. VENDOR RESPONSE The vendor has not responded to communication regarding this vulnerability. The vulnerability appears to have been silently fixed in Winamp 5.13 which is available for download at: http://www.winamp.com/player/ VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2006-0476 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 12/15/2005 Initial vendor notification 02/01/2006 Public disclosure IX. CREDIT This vulnerability was independently discovered by Alan Mccaig (b0f) b0fnet (at) yahoo (dot) com [email concealed] and Ruben Santamarta (ruben (at) reversemode (dot) com [email concealed]). Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.idefense.com X. LEGAL NOTICES Copyright (c) 2006 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 (at) idefense (dot) com [email concealed] 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.