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Cumulative Patches for Excel and Word for Windows (Q324458)

Date: 19 June 2002
Software: Microsoft Office for Windows
Impact: Run Code of Attacker's Choice
Max Risk: Moderate
Bulletin: MS02-031

Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS02-031.asp.

Affected Software:

Microsoft Excel 2000 for Windows
Microsoft Office 2000 for Windows
Microsoft Excel 2002 for Windows
Microsoft Word 2002 for Windows
Microsoft Office XP for Windows

This is a set of cumulative patches that, when applied, applies all previously released fixes for these products.

In addition, these patches eliminate four newly discovered vulnerabilities all of which could enable an attacker to run Macro code on a user's machine.

Read more: MS02-031

Issue:
======
This is a set of cumulative patches that, when applied, applies all
previously released fixes for these products.

In addition, these patches eliminate four newly discovered
vulnerabilities all of which could enable an attacker to run Macro
code on a user's machine. The attacker's macro code could take
any actions on the system that the user was able to.

- An Excel macro execution vulnerability that relates to how inline
macros that are associated with objects are handled. This
vulnerability could enable macros to execute and bypass the
Macro Security Model when the user clicked on an object in
a workbook.

- An Excel macro execution vulnerability that relates to how macros
are handled in workbooks when those workbooks are opened via a
hyperlink on a drawing shape. It is possible for macros in a
workbook so invoked to run automatically.

- An HTML script execution vulnerability that can occur when
an Excel workbook with an XSL Stylesheet that contains HTML
scripting is opened. The script within the XSL stylesheet
could be run in the local computer zone.

- A new variant of the "Word Mail Merge" vulnerability first
addressed in MS00-071. This new variant could enable an
attacker's macro code to run automatically if the user had
Microsoft Access present on the system and chose to open a
mail merge document that had been saved in HTML format.

Mitigating Factors:
====================
Excel Inline Macros Vulnerability:

- A successful attack exploiting this vulnerability would require
that the user accept and open a workbook from an attacker and
then click on an object within the workbook.

Hyperlinked Excel Workbook Macro Bypass:

- A successful attempt to exploit this vulnerability would require
that the user accept and open an attacker's workbook and click on
a drawing shape with a hyperlink.

- An attacker's destination workbook would have to be accessible to
the user, either on the local system on an accessible network
location.

Excel XSL Stylesheet Script Execution:

- A user would have to accept and open an attacker's workbook to
exploit this vulnerability.

- In addition, the user would have to acknowledge a security
warning by selecting the non-default option.

Variant of MS00-071, Word Mail Merge Vulnerability:

- The Word mail merge document would have to be saved in HTML
format. As Word is not the default handler for HTML
applications, the user would have to choose to open the document
in Word, or acknowledge a security warning.

- A successful attack requires that Access be installed locally.

- The attacker's data source has to be accessible to the user
across a network.

Risk Rating:
============
- Internet systems: Low
- Intranet systems: Low
- Client systems: Moderate

Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-031.asp
for information on obtaining this patch.

Acknowledgment:
===============
- Darryl Higa for reporting the Excel Inline Macros and
Hyperlinked Excel Workbook Macro Bypass vulnerabilities.

- The dH team and SECURITY.NNOV team (http://www.security.nnov.ru/)
for reporting the variant of MS00-071.