__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Cumulative Patch for Internet Explorer (IE) [Microsoft Security Bulletin MS03-015] April 24, 2003 20:00 GMT Number N-082 ______________________________________________________________________________ PROBLEM: There are four vulnerabilities in Microsoft Internet Explorer: (1) A buffer overrun vulnerability occurs in URLMON.DLL because IE does not correctly check the parameters of information being received from a web server. (2) A vulnerability in the IE file upload control that allows input from a script to be passed to the upload control. (3) A flaw in the way IE handles the rendering of third party files. (4) A flaw in the way modal dialogs are treated by IE because an input parameter is not properly checked. SOFTWARE: * Microsoft Internet Explorer 5.01 * Microsoft Internet Explorer 5.5 * Microsoft Internet Explorer 6.0 DAMAGE: The most serious of these vulnerabilities could enable an attacker to execute arbitrary code on a user's system if the user either browsed to a hostile web site or opened a specially crafted HTML email message. SOLUTION: Apply patch as indicated in Microsoft's bulletin. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. An attacker would have to host a web site ASSESSMENT: or send a malicious email that contained a web page used to exploit the particular vulnerability. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-082.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/ default.asp?url=/technet/security/bulletin/MS03-015.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS03-015 *****] Microsoft Security Bulletin MS03-015 Cumulative Patch for Internet Explorer (813489) Originally posted: April 23, 2003 Summary Who should read this bulletin: Customers using Microsoft® Internet Explorer. Impact of vulnerability: Four new vulnerabilities, the most serious of which could enable an attacker to execute arbitrary code on a user’s system if the user either browsed to a hostile web site or opened a specially crafted HTML email message. Maximum Severity Rating: Critical Recommendation: System administrators should install the patch immediately Affected Software: * Microsoft Internet Explorer 5.01 * Microsoft Internet Explorer 5.5 * Microsoft Internet Explorer 6.0 Technical details Technical description: This is a cumulative patch that includes the functionality of all previously released patches for Internet Explorer 5.01, 5.5 and 6.0. In addition, it eliminates the following four newly discovered vulnerabilities: * A buffer overrun vulnerability in URLMON.DLL that occurs because Internet Explorer does not correctly check the parameters of information being received from a web server. It could be possible for an attacker to exploit this vulnerability to run arbitrary code on a user's system. A user simply visiting an attacker’s website could allow the attacker to exploit the vulnerability without any other user action. * A vulnerability in the Internet Explorer file upload control that allows input from a script to be passed to the upload control. This vulnerability could allow an attacker to supply a file name to the file upload control and automatically upload a file from the user’s system to a web server. * A flaw in the way Internet Explorer handles the rendering of third party files. The vulnerability results because the Internet Explorer method for rendering third party file types does not properly check parameters passed to it. An attacker could create a specially formed URL that would inject script during the rendering of a third party file format and cause the script to execute in the security context of the user. * A flaw in the way modal dialogs are treated by Internet Explorer that occurs because an input parameter is not properly checked. This flaw could allow an attacker to use an injected script to provide access to files stored on a user’s computer. Although a user who visited the attacker’s website could allow the attacker to exploit the vulnerability without any other user action, an attacker would have no way to force the user to visit the website. In addition to eliminating the above vulnerabilities, this patch also includes a fix for Internet Explorer 6.0 SP1 that corrects the method by which Internet Explorer displays help information in the local computer zone. While we are not aware of a method to exploit this vulnerability by itself, if it were possible to exploit it, it could allow an attacker to read local files on a visiting user’s system. This patch also sets the Kill Bit on the Plugin.ocx ActiveX control which has a security vulnerability. This killbit has been set in order to ensure that the vulnerable control cannot be reintroduced onto users’ systems and to ensure that users who already have the vulnerable control on their system are protected. This issue is discussed further in Microsoft Knowledge Base Article 813489. Like the previous Internet Explorer cumulative patch released with bulletin MS03-004, this cumulative patch will cause window.showHelp( ) to cease to function if you have not applied the HTML Help update. If you have installed the updated HTML Help control from Knowledge Base article 811630, you will still be able to use HTML Help functionality after applying this patch. Mitigating factors: There are common mitigating factors across all of the vulnerabilities: * The attacker would have to host a web site that contained a web page used to exploit the particular vulnerability. * By default, Outlook Express 6.0 and Outlook 2002 open HTML mails in the Restricted Sites Zone. In addition, Outlook 98 and 2000 open HTML mails in the Restricted Sites Zone if the Outlook Email Security Update has been installed. Customers who use any of these products would be at no risk from an e-mail borne attack that attempted to automatically exploit these vulnerabilities. The attacker would have no way to force users to visit a malicious web site. Instead, the attacker would need to lure them there, typically by getting them to click on a link that would take them to the attacker's site. In addition to the common factors, there are a number of individual mitigating factors: URLMON.DLL Buffer Overrun: * Code that executed on the system would only run under the privileges of the locally logged in user. File Upload Control vulnerability: * The attacker would have to know the explicit path and name of the file to be uploaded in advance. Third Party plug-in rendering: * The third party plugin would have to be present on the user’s system in order for it to be exploited Severity Rating: Internet Explorer Internet Explorer Internet Explorer Internet Explorer 5.01 SP3 5.5 SP2 6.0 Gold 6.0 SP1 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ URLMON.DLL Critical Critical Critical Critical ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ File Upload Control Vulnerability Moderate Moderate Moderate Moderate ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Third Party Plugin Rendering Critical Critical Critical Critical ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Model Dialog Script Execution Critical Critical Critical Critical ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Aggregate Severity of all issues included in this patch Critical Critical Critical Critical ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The above assessment is based on the types of systems affected by the vulnerability, their typical deployment patterns, and the effect that exploiting the vulnerability would have on them. Vulnerability identifier: * URLMON.DLL Buffer Overrun: CAN-2003-0113 * File Upload Control vulnerability: CAN-2003-0114 * Third Party plug-in rendering: CAN-2003-0115 * Model Dialog script execution: CAN-2003-0116 Tested Versions: Internet Explorer versions 5.01 Service Pack 3, Internet Explorer 5.5 SP2, Internet Explorer 6.0 and Internet Explorer 6.0 SP1 were tested for these vulnerabilities. Previous versions are no longer supported, and may or may not be affected by these vulnerabilities. More information on Windows Operating System Components Lifecycles is available from: http://microsoft.com/windows/lifecycle/desktop/consumer/components.mspx. Patch availability Download locations for this patch http://www.microsoft.com/windows/ie/downloads/critical/813489/default.asp Additional information about this patch Installation platforms: * IE5.01 running on Windows 2000 systems with Service Pack 3 installed. * The IE 5.5 patch can be installed on systems running Internet Explorer 5.5 Service Pack 2. * The IE 6.0 patch can be installed on systems running IE 6.0 Gold or Internet Explorer 6.0 Service Pack 1. Inclusion in future service packs: The fix for this issue will be included in Internet Explorer 6.0 Service Pack 2. Reboot needed: Yes Patch can be uninstalled: Yes Superseded patches: This patch supersedes the one provided in Microsoft Security Bulletin MS03-004, which is itself a cumulative patch. Verifying patch installation: * To verify that the patch has been installed on the machine, open IE, select Help, then select About Internet Explorer and confirm that Q813489 is listed in the Update Versions field. * To verify the individual files, use the patch manifest provided in Knowledge Base article 813489. Caveats: If you have not installed the updated HTML Help control from Knowledge Base article 811630, you will not be able to use some HTML Help functionality after applying this update. In order to restore that functionality, users need to download the updated HTML Help control (811630). Users should also note that when the latest version of HTML Help is installed, the following limitations will occur when a help file is opened with the showHelp method: * Only supported protocols can be used with showHelp to open a web page or help (chm) file. * The shortcut function supported by HTML Help will be disabled when the help file is opened with showHelp This will not affect the shortcut functionality if the same CHM file is opened by the user manually by double-clicking on the help file, or by through an application on the local system using the HTMLHELP( ) API. Localization: Localized versions of this patch are available at the locations discussed in “Patch Availability”. Obtaining other security patches: Patches for other security issues are available from the following locations: * Security patches are available from the Microsoft Download Center, and can be most easily found by doing a keyword search for "security_patch". * Patches for consumer platforms are available from the WindowsUpdate web site Other information: Acknowledgments Microsoft thanks the following for working with us to protect customers: Mark Litchfield of Next Generation Security Software Ltd. for reporting the PLUGIN.OCX issue to us. Andreas Sandblad, Sweden for reporting the showhelp issue to us. Jouko Pynnönen of Oy Online Solutions Ltd, Finland for reporting the URLMON.DLL Buffer Overrun issue to us. Support: * Microsoft Knowledge Base article 813489 discusses this issue. Knowledge Base articles can be found on the Microsoft Online Support web site. * Technical support is available from Microsoft Product Support Services. There is no charge for support calls associated with security patches. Security Resources: The Microsoft TechNet Security Web Site provides additional information about security in Microsoft products. Disclaimer: The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Revisions: * V1.0 April 23, 2003: Bulletin Created. [***** End Microsoft Security Bulletin MS03-015 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corporation for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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