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: www.microsoft.com/technet/security/bulletin/MS02-031.asp. 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 www.microsoft.com/technet/security/bulletin/ms02-031.asp for information on obtaining this patch.