Vulnerability Note VU#996892

Data used by Microsoft Word to construct a destination address for a memory copy routine is embedded within a Word document itself. If an attacker constructs a Word document with a specially crafted value used to build this destination address, then that attacker may be able to overwrite arbitrary memory.

An attacker could trigger this vulnerability by convincing a user to open a specially crafted Word document.

Exploit code for this vulnerability is publicly available.

The specific consequences of this vulnerability are unclear, but may include execution of arbitrary code and denial of service.

Apply Update for Microsoft
Microsoft has addressed this vulnerability in Microsoft Security Bulletin MS07-014.

Do not open untrusted Word documents

Do not open unfamiliar or unexpected Word or other Office documents, particularly those hosted on web sites or delivered as email attachments. Please see Cyber Security Tip ST04-010.

Do not rely on file name extension filtering

In most cases, Windows will call Word to open a document even if the document has an unknown file extension. For example, if document.qwer contains the correct file header information, Windows will open document.qwer with Word. Filtering for common extensions (e.g., .doc, and .dot) will not detect all Word documents.

Disable automatic opening of Microsoft Office documents

By default, Microsoft Office 97 and Microsoft Office 2000 will configure Internet Explorer to automatically open Microsoft Office documents. This feature can be disabled by using the Office Document Open Confirmation Tool. Mozilla Firefox users should disable automatic opening of files, as specified in the Securing Your Web Browser document.