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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® Windows® 95 and 98, and Windows NT® 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/technet/security/bulletin/fq00-005.mspx

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General Information

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.

Vulnerability Identifier: CVE-2000-0073

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Patch Availability

•

Windows 95: http://www.microsoft.com/windows95/downloads/contents/WUCritical/rtfcontrol/Default.asp

•

Window 98: http://support.microsoft.com/ph/1139

•

Windows NT 4.0 Workstation, Windows NT 4.0 Server, and Windows NT 4.0 Server, Enterprise Edition:

•

Intel:

http://www.microsoft.com/Downloads/details.aspx?displaylang=en&FamilyID=22D42B3D-3006-42F7-A7FE-5D5E8334063F

•

Alpha:

http://www.microsoft.com/Downloads/details.aspx?displaylang=en&FamilyID=D5C0929F-EBCC-4A5C-B81F-1A6F42DB7AA6

•

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

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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/technet/security/bulletin/fq00-005.mspx.
•	Microsoft Knowledge Base (KB) article 249973, Default RTF File Viewer Interrupts Normal Application Processing, http://support.microsoft.com/default.aspx?scid=kb;en-us;249973&sd=tech. (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://msdn2.microsoft.com/en-us/library/aa140295(office.10).aspx.
•	Microsoft Security web site.

Obtaining Support on this Issue

This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/contactussupport/?ws=support.

Revisions

•	January 17, 2000: Bulletin Created.

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