__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Cumulative Patch for Internet Explorer (IE) [Microsoft Security Bulletin MS03-020] June 4, 2003 19:00 GMT Number N-101 ______________________________________________________________________________ PROBLEM: There are two new vulnerabilities in Microsoft Internet Explorer: (1) A buffer overrun vulnerability that occurs because Internet Explorer does not properly determine an object type returned from a web server. (2) A flaw that results because Internet Explorer does not implement an appropriate block on a file download dialog box. SOFTWARE: Microsoft Internet Explorer 5.01 Microsoft Internet Explorer 5.5 Microsoft Internet Explorer 6.0 Microsoft Internet Explorer 6.0 for Windows Server 2003 DAMAGE: 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-101.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url= /technet/security/bulletin/MS03-020.asp PATCHES: http://www.microsoft.com/windows/ie/downloads/critical /818529/default.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS03-020 *****] Microsoft Security Bulletin MS03-020 Cumulative Patch for Internet Explorer (818529) Originally posted: June 4, 2003 Summary Who should read this bulletin: Customers using Microsoft® Internet Explorer Impact of vulnerability: Allow an attacker to execute code on a user’s system Maximum Severity Rating: Critical Recommendation: System administrators should install the patch immediately End User Bulletin: An end user version of this bulletin is available at: http://www.microsoft.com/security/security_bulletins/ms03-020.asp. Affected Software: Microsoft Internet Explorer 5.01 Microsoft Internet Explorer 5.5 Microsoft Internet Explorer 6.0 Microsoft Internet Explorer 6.0 for Windows Server 2003 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 two newly discovered vulnerabilities: A buffer overrun vulnerability that occurs because Internet Explorer does not properly determine an object type returned from a web server. It could be possible for an attacker who exploited this vulnerability to run arbitrary code on a user's system. If a user visited an attacker’s website, it would be possible for the attacker to exploit this vulnerability without any other user action. An attacker could also craft an HTML email that attempted to exploit this vulnerability. A flaw that results because Internet Explorer does not implement an appropriate block on a file download dialog box. It could be possible for an attacker to exploit this vulnerability to run arbitrary code on a user's system. If a user simply visited an attacker’s website, it would be possible for the attacker to exploit this vulnerability without any other user action. An attacker could also craft an HTML email that attempted to exploit this vulnerability. In order to exploit these flaws, the attacker would have to create a specially formed HTML email and send it to the user. Alternatively an attacker would have to host a malicious web site that contained a web page designed to exploit these vulnerabilities. The attacker would then have to persuade a user to visit that site. As with the previous Internet Explorer cumulative patches released with bulletins MS03-004 and MS03-015, 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: The following mitigating factors apply to both vulnerabilities discussed in this bulletin: By default, Internet Explorer on Windows Server 2003 runs in Enhanced Security Configuration. This default configuration of Internet Explorer blocks these attacks. If Internet Explorer Enhanced Security Configuration has been disabled, the protections put in place that prevent these vulnerabilities from being exploited would be removed. In the Web based attack scenario, the attacker would have to host a web site that contained a web page used to exploit these vulnerabilities. An attacker would have no way to force users to visit a malicious web site outside of the HTML email vector. 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. Code that executed on the system would only run under the privileges of the logged in user. Severity Rating: Object Tag Vuln File Download Vuln IE 5.01 SP3 Critical Critical IE 5.5 SP2 Critical Critical IE 6.0 Gold Critical Critical IE 6.0 SP1 Critical Critical IE 6.0 for Windows Server 2003 Moderate Moderate 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. The moderate severity rating on Windows Server 2003 is based on Internet Explorer Enhanced Security Configuration. Vulnerability identifier: Object Tag Vulnerability: CAN-2003-0344 File Download Dialog Vulnerability: CAN-2003-0309 Tested Versions: Internet Explorer versions 5.01 Service Pack 3, Internet Explorer 5.5 SP2, Internet Explorer 6.0, Internet Explorer 6.0 SP1, and Internet Explorer 6.0 for Windows Server 2003 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/818529/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 Service Pack 2. The IE 6.0 patch can be installed on systems running IE 6.0 Gold or Service Pack 1. Inclusion in future service packs: The fix for these issues will be included in Windows XP Service Pack 2 and Windows Server 2003 Service Pack 1 Reboot needed: Yes Patch can be uninstalled: Yes Superseded patches: This patch supersedes the one provided in Microsoft Security Bulletin MS03-015, which is itself a cumulative patch. Verifying patch installation: To verify that the patch has been installed on the machine, open Internet Explorer, select Help, then select About Internet Explorer and confirm that Q818529 is listed in the Update Versions field. Note that you can not use this method on Windows Server 2003 or Windows XP 64-Bit Edition Version 2003, as the Update Versions field is not updated by the package for these operating systems. To verify the individual files, use the patch manifest provided in Knowledge Base article 818529. 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 eEye Digital Security for reporting this issue to us and working with us to protect customers. Support: Microsoft Knowledge Base article 818529 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. Scanning for Updates: As part of Microsoft's Strategic Technology Protection Program, and in response to direct customer need for a streamlined method of identifying common security misconfigurations, Microsoft has developed the Microsoft Baseline Security Analyzer (MBSA). MBSA version 1.1.1 adds support for Windows Server 2003 and will be available approximately 24 hours after the release of this bulletin at the following location: http://www.microsoft.com/technet/treeview/default.asp?url= /technet/security/tools/Tools/MBSAhome.asp 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 (June 4, 2003): Bulletin published. [***** End Microsoft Security Bulletin MS03-020 *****] _______________________________________________________________________________ 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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