Vulnerability in Excel Could Allow Remote Code Execution

Microsoft is investigating new public reports of limited ?zero-day? attacks using a vulnerability in Microsoft Excel 2003, Excel Viewer 2003, Excel 2002, Excel 2000, Microsoft Excel 2004 for Mac, and Microsoft Excel v. X for Mac. In order for this attack to be carried out, a user must first open a malicious Excel file attached to an e-mail or otherwise provided to them by an attacker.

Opening the Excel document out of email will prompt the user to be careful about opening the attachment.

As a best practice, users should always exercise extreme caution when opening unsolicited attachments from both known and unknown sources. Microsoft has added detection to the Windows Live Safety Center today for up-to-date removal of malicious software that attempts to exploit this vulnerability.

Microsoft is also actively sharing information with Microsoft Security Response Alliance partners so that their detection can be up to date to detect and remove attacks.

Customers in the U.S. and Canada who believe they are affected can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.

International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs.