__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft "Excel SYLK" Vulnerability October 27, 1999 15:00 GMT Number K-004 ______________________________________________________________________________ PROBLEM: Two vulnerabilities exist in Microsoft(r) Excel 97 or 2000 which may allow macros to execute, bypassing the macro warning notices. PLATFORM: Microsoft Windows 95/98 or NT running Excel 97 or 2000 DAMAGE: When a file containing a malicious macro is opened, it could take any action the targeted user could take. This could include creating, deleting, or modifying files on the users computer. SOLUTION: Apply the patch. ______________________________________________________________________________ VULNERABILITY The risk is low. A user would have to open a file containing a ASSESSMENT: malicious macro. ______________________________________________________________________________ [Start Microsoft Advisory] Microsoft Security Bulletin (MS99-044) -------------------------------------- Patch Available for "Excel SYLK" Vulnerability Originally Posted: October 20, 1999 Summary ======= Microsoft has released a patch that eliminates two vulnerabilities in Microsoft(r) Excel 97 and 2000 that could allow macros to run without warning under certain conditions. Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/security/bulletins/MS99-044faq.asp. Issue ===== The primary vulnerability addressed by this patch is the "Excel SYLK" vulnerability. Symbolic Link (SYLK) files can contain macros; if such a file were opened in Excel 97 or 2000, the macro would run without asking for the user's permission. These macros could take any action on the computer that the user could take. This patch also eliminates a vulnerability involving how Excel 97 imports macros created by Lotus 1-2-3 or Quattro Pro. When such a macro is imported, Excel 97 runs it without asking for the user's permission. These macros could be used to delete files on the user's computer, but could take no other action. Affected Software Versions ========================== - Microsoft Excel 97, whether shipped alone or as part of Office 97. - Microsoft Excel 2000, whether shipped alone or as part of Office 2000. Patch Availability ================== - Excel 97: http://officeupdate.microsoft.com/downloadDetails/Xl8p7pkg.htm - Excel 2000: http://officeupdate.microsoft.com/2000/downloadDetails/XL9p1pkg.htm More Information ================ Please see the following references for more information related to this issue. - Microsoft Security Bulletin MS99-044: Frequently Asked Questions, http://www.microsoft.com/security/bulletins/MS99-044faq.asp. - Microsoft Knowledge Base (KB) article Q241900, XL97: Opening Lotus 1-2-3 File May Execute Macro Without Warning, http://support.microsoft.com/support/kb/articles/q241/9/00.asp. - Microsoft Knowledge Base (KB) article Q241901, XL2000: Macro Virus Warning Does Not Appear Opening SYLK File, http://support.microsoft.com/support/kb/articles/q241/9/01.asp. - Microsoft Knowledge Base (KB) article Q241902, XL97: Macro Virus Warning Does Not Appear Opening SYLK File, http://support.microsoft.com/support/kb/articles/q241/9/02.asp. - Microsoft Security Advisor web site, http://www.microsoft.com/security/default.asp. NOTE: It may take 24 hours from the original posting of this bulletin for the KB articles to be visible. 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. Acknowledgments =============== Microsoft acknowledges David Young of Derby, UK, for bringing the "Excel SYLK" vulnerability to our attention. Revisions ========= - October 20, 1999: 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. 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. (c) 1999 Microsoft Corporation. All rights reserved. Terms of Use. ******************************************************************* You have received this e-mail bulletin as a result of your registration to the Microsoft Product Security Notification Service. You may unsubscribe from this e-mail notification service at any time by sending an e-mail to MICROSOFT_SECURITY-SIGNOFF-REQUEST@ANNOUNCE.MICROSOFT.COM The subject line and message body are not used in processing the request, and can be anything you like. 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 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. 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