__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft "Malformed RTF Control Word" Vulnerability January 24, 2000 18:00 GMT Number K-017 ______________________________________________________________________________ PROBLEM: Microsoft has identified a vulnerability in rich text format files (RTF). PLATFORM: Microsoft Windows 95/98 and NT Workstation and Server DAMAGE: Microsoft believes that this is a denial of service vulnerability only, and that there is no capability to use this vulnerability to run arbitrary code. SOLUTION: Apply the patch. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. The information about the vulnerability is ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start Microsoft Advisory ] Microsoft Security Bulletin (MS00-005) -------------------------------------- Patch Available for "Malformed RTF Control Word" Vulnerability Originally Posted: January 17, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in the Rich Text Format (RTF) reader that ships as part of Microsoft(r) Windows(r) 95 and 98, and Windows NT(r) 4.0. Under certain conditions, the vulnerability could be used to cause email programs to crash. Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/security/bulletins/MS00-005faq.asp. Issue ===== RTF files consist of text and control information. The control information is specified via directives called control words. The default RTF reader that ships as part of many Windows platforms has an unchecked buffer in the portion of the reader that parses control words. If an RTF file contains a specially-malformed control word, it could cause the application to crash. Microsoft believes that this is a denial of service vulnerability only, and that there is no capability to use this vulnerability to run arbitrary code. The most serious risk from this vulnerability would result if a user had preview mode enabled on a mail program like Outlook, and received an email that exploited the vulnerability. Because preview mode causes the mail to be parsed without user assent, the mail program would continue to crash until a subsequent mail was received or the mail program was started with preview mode disabled. Affected Software Versions ========================== - Microsoft Windows 95 - Microsoft Windows 98 - Microsoft Windows 98 Second Edition - Microsoft Windows NT 4.0 Workstation - Microsoft Windows NT 4.0 Server - Microsoft Windows NT 4.0 Server, Enterprise Edition - Microsoft Windows NT 4.0 Server, Terminal Server Edition NOTE: Windows 2000 is not affected by this vulnerability. Patch Availability ================== - Windows 95: http://www.microsoft.com/windows95/downloads/contents/ WUCritical/rtfcontrol/default.asp - Window 98: http://www.microsoft.com/windows98/downloads/contents/ WUCritical/rtfcontrol/default.asp - Windows NT 4.0 Workstation, Windows NT 4.0 Server, and Windows NT 4.0 Server, Enterprise Edition: Intel: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17510 Alpha: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17511 - Windows NT 4.0 Server, Terminal Server Edition: To be released shortly. NOTE: The Windows 95 and 98 versions of the patch will also be available via WindowsUpdate shortly. When this happens, we will modify the bulletin to note this fact. NOTE: Additional security patches are available at the Microsoft Download Center More Information ================ Please see the following references for more information related to this issue. - Frequently Asked Questions: Microsoft Security Bulletin MS00-005, http://www.microsoft.com/security/bulletins/MS00-005faq.asp. - Microsoft Knowledge Base (KB) article Q249973, Default RTF File Viewer Interrupts Normal Application Processing, http://support.microsoft.com/support/kb/articles/q249/9/73.asp. (Note: It may take 24 hours from the original posting of this bulletin for this KB article to be visible.) - Rich Text Format (RTF) Specification and Sample RTF Reader Program, Version 1.5, http://msdn.microsoft.com/library/specs/ richtextformatrtfspecificationsamplertfreaderprogramversion15.htm - Microsoft Security Advisor web site, http://www.microsoft.com/security/default.asp. Obtaining Support on this Issue =============================== This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/support/contact/default.asp. Revisions ========= - January 17, 2000: Bulletin Created. ------------------------------------------------------------------------- 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. 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For more information on the Microsoft Security Notification Service please visit http://www.microsoft.com/security/services/bulletin.asp. For security-related information about Microsoft products, please visit the Microsoft Security Advisor web site at http://www.microsoft.com/security. [ End Microsoft Advisory ] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft 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. 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