From idlabs-advisories@idefense.com Tue Mar 1 16:42:59 2005 From: idlabs-advisories@idefense.com To: idlabs-advisories@idefense.com Date: Tue, 1 Mar 2005 16:12:55 -0500 Reply-To: labs-no-reply@idefense.com Subject: [Full-Disclosure] iDEFENSE Security Advisory 03.01.05: RealNetworks RealPlayer .smil Buffer Overflow Vulnerability RealNetworks RealPlayer .smil Buffer Overflow Vulnerability iDEFENSE Security Advisory 03.01.05 www.idefense.com/application/poi/display?id=209&type=vulnerabilities March 1, 2005 I. BACKGROUND RealPlayer is an application for playing various media formats, developed by RealNetworks Inc. For more information, visit http://www.real.com/. II. DESCRIPTION Remote exploitation of a stack-based buffer overflow vulnerability in the The Synchronized Multimedia Integration Language (smil) file format parser within various versions of RealNetworks Inc.'s RealPlayer could allow attackers to execute arbitrary code. The vulnerability specifically exists due to an unbounded string copying operation. The vulnerable code is shown below: datatype/smil/renderer/smil1/smlparse.cpp CSmil1Parser::testAttributeFailed(SMIL1Node* pNode) line 2878 *** if(HXR_OK == rc) { UINT32 ulScreenHeight = 0; UINT32 ulScreenWidth = 0; const char* pScreenSize = (const char*)pBuf->GetBuffer(); // format is screen-height "X" screen-width char tmp[256]; /* Flawfinder: ignore */ strcpy(tmp, pScreenSize); /* Flawfinder: ignore */ *** The pBuf object's datapointer (which is what GetBuffer uses internally) is pointing at the screen-size attribute in the user-supplied smil file. This allows a fixed stack buffer to be overwritten with user-supplied data. An attacker could use this stack overwrite to manipulate a saved return address or Structured Exception Handler, allowing for arbitrary code execution. In order to trigger this vulnerability, one would need an otherwise valid .smil file with the following line added in an appropriate section: Note that "LONGSTRING" should be more than 256 bytes in order to cause stack corruption. III. ANALYSIS Exploitation allows for arbitrary code execution as the user who opened the .smil file. Exploitation requires an attacker to craft a malicious .smil and convince a user to open it. An attacker could also force a web browser to refresh and automatically load the .smil file from a normal web page under the attacker's control. In default installations of RealPlayer under Windows, Internet Explorer will not prompt the user for an action when encountering a .smil file. It will open it without delay, thus allowing a more effective method of exploitation. IV. DETECTION iDEFENSE Labs has confirmed that Real Networks Inc.'s RealPlayer 10.5 (6.0.12.1056) on Windows and RealPlayer 10 (10.0.1.436) on Linux are vulnerable. The vendor has reported that the following products are vulnerable on the following platforms: Windows: RealPlayer 10.5 (6.0.12.1056 and below) RealPlayer 10 RealOne Player V2 RealOne Player V1 RealPlayer 8 RealPlayer Enterprise Mac RealPlayer 10 (10.0.0.325 and below) RealOne Player Linux RealPlayer 10 Helix Player V. WORKAROUND There are no known workarounds for this vulnerability. Although .smil files can be disassociated from RealPlayer, it is still possible to cause these files to load with RealPlayer using other methods. One such method is loading the file via one of the many ActiveX Controls that RealPlayer contains. Any effective workaround would prevent RealPlayer from functioning. VI. VENDOR RESPONSE A vendor advisory for this issue is available at: http://service.real.com/help/faq/security/050224_player VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the names CAN-2005-0455 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 01/14/2005 Initial vendor notification 01/19/2005 Initial vendor response 03/01/2005 Coordinated 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 Free tools, research and upcoming events http://labs.idefense.com X. LEGAL NOTICES Copyright (c) 2005 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@idefense.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. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html