MPlayer MMST Streaming Stack Overflow Vulnerability iDEFENSE Security Advisory 12.16.04 http://www.idefense.com/application/poi/display?id=167 December 16, 2004 I. BACKGROUND MPlayer is a movie player for Linux that also runs on many other Unices, and non- x86 CPUs. It plays most MPEG, VOB, AVI, Ogg/OGM, VIVO, ASF/WMA/WMV, QT/MOV/MP4, FLI, RM, NuppelVideo, YUV4MPEG, FILM, RoQ, PVA files, supported by many native, XAnim, and Win32 DLL codecs. You can watch VideoCD, SVCD, DVD, 3ivx, DivX 3/4/5 and other formats. More information is available at http://mplayerhq.hu/. II. DESCRIPTION Remote exploitation of a stack overflow vulnerability in MPlayer could allow remote users to gain access to the computer. The vulnerability specifically exists due to a lack of bounds checking in /libmpdemux/asf_mmst_straming.c. If a specially crafted file specifies a large value for the length field, the overflow is triggered in get_data(). The vulnerable code follows: static int get_media_packet (int s, int padding, streaming_ctrl_t *stream_ctrl) { unsigned char pre_header[8]; char data[BUF_SIZE]; [...] packet_len = get_32 ((unsigned char*)&packet_len, 0) + 4; [!] if (!get_data (s, data, packet_len)) { printf ("command data read failed\n"); return 0; } [...] Once the get_data function overwrites stack memory, the saved return address can be controlled, thus allowing for execution of arbitrary code. III. ANALYSIS If remote exploitation is successful, the attacker would be able to gain access with the privileges of the user who attempted to view the stream. IV. DETECTION iDEFENSE has confirmed that MPlayer version 1.0pre5 is vulnerable. The following distributions of Linux include MPlayer: Debian Linux Fedora Linux Gentoo Linux SUSE Linux V. WORKAROUND Users must be careful when accepting and opening media from untrusted sources. Do not accept media from those you do not trust. Do not stream media from servers you do not trust. VI. VENDOR RESPONSE A patch to address this vulnerability is available at: http://www1.mplayerhq.hu/MPlayer/patches/mmst_fix_20041215.diff VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 12/10/2004 Initial vendor notification 12/16/2004 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 © 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@xxxxxxxxxxxx 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.
