Security Bulletin

Microsoft Security Bulletin MS99-044 - Critical

Patch Available for "Excel SYLK" Vulnerability

Published: October 20, 1999

Version: 1.0

Originally Posted: October 20, 1999

Summary

Microsoft has released a patch that eliminates two vulnerabilities in Microsoft® 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 https://www.microsoft.com/technet/security/bulletin/fq99-044.mspx.

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.

Vulnerability Identifier: CVE-1999-0794

Patch Availability

More Information

Please see the following references for more information related to this issue.

  • Microsoft Security Bulletin MS99-044: Frequently Asked Questions, https://www.microsoft.com/technet/security/bulletin/fq99-044.mspx.
  • Microsoft Knowledge Base (KB) article 241900, XL97: Opening Lotus 1-2-3 File May Execute Macro Without Warning, https:.
  • Microsoft Knowledge Base (KB) article 241901, XL2000: Macro Virus Warning Does Not Appear Opening SYLK File, </https:>https:.
  • Microsoft Knowledge Base (KB) article 241902, XL97: Macro Virus Warning Does Not Appear Opening SYLK File, </https:>https:.
  • Microsoft Security web site, </https:>https:.
    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 </https:>https:.

Acknowledgments

Microsoft acknowledges David Young of Derby, UK, for bringing the "Excel SYLK" vulnerability to our attention.

Revisions

  • October 20, 1999: Bulletin Created.

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