Title: Flaw in Microsoft Word Could Enable Macros to Run Automatically (827653) Date: September 3, 2003 Software: Microsoft Word 97 Microsoft Word 98 (J) Microsoft Word 2000 Microsoft Word 2002 Microsoft Works Suite 2001 Microsoft Works Suite 2002 Microsoft Works Suite 2003 Impact: Run macros without warning Max Risk: Important Bulletin: MS03-035 Microsoft encourages customers to review the Security Bulletins at: http://www.microsoft.com/technet/security/bulletin/MS03-035.asp http://www.microsoft.com/security/security_bulletins/MS03-035.asp - ------------------------------------------------------------------- Issue: ====== A macro is a series of commands and instructions that can be grouped together as a single command to accomplish a task automatically. Microsoft Word supports the use of macros to allow the automation of commonly performed tasks. Since macros are executable code it is possible to misuse them, so Microsoft Word has a security model designed to validate whether a macro should be allowed to execute depending on the level of macro security the user has chosen. A vulnerability exists because it is possible for an attacker to craft a malicious document that will bypass the macro security model. If the document was opened, this flaw could allow a malicious macro embedded in the document to be executed automatically, regardless of the level at which macro security is set. The malicious macro could take the same actions that the user had permissions to carry out, such as adding, changing or deleting data or files, communicating with a web site or formatting the hard drive. The vulnerability could only be exploited by an attacker who persuaded a user to open a malicious document - there is no way for an attacker to force a malicious document to be opened. Mitigating Factors: ==================== - The user must open the malicious document for an attacker to be successful. An attacker cannot force the document to be opened automatically. - The vulnerability cannot be exploited automatically through e- mail. A user must open an attachment sent in e-mail for an e- mail borne attack to be successful. - By default, Outlook 2002 block programmatic access to the Address Book. In addition, Outlook 98 and 2000 block programmatic access to the Outlook Address Book if the Outlook Email Security Update has been installed. Customers who use any of these products would not be at risk of propagating an e-mail borne attack that attempted to exploit this vulnerability. - The vulnerability only affects Microsoft Word - other members of the Office product family are not affected. Risk Rating: ============ -Important Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletins at http://www.microsoft.com/technet/security/bulletin/MS03-035.asp http://www.microsoft.com/security/security_bulletins/MS03-035.asp for information on obtaining this patch. Acknowledgment: =============== - Jim Bassett of Practitioners Publishing Company (http://www.ppcnet.com) - ------------------------------------------------------------------- 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.