The Microsoft Office Web Components Spreadsheet ActiveX control (aka OWC10 or OWC11), as distributed in Office XP SP3 and Office 2003 SP3, Office XP Web Components SP3, Office 2003 Web Components SP3, Office 2003 Web Components SP1 for the 2007 Microsoft Office System, Internet Security and Acceleration (ISA) Server 2004 SP3 and 2006 Gold and SP1, and Office Small Business Accounting 2006, when used in Internet Explorer, allows remote attackers to execute arbitrary code via a crafted call to the msDataSourceObject method, as exploited in the wild in July and August 2009, aka "Office Web Components HTML Script Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5809
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-043
http://www.us-cert.gov/cas/techalerts/TA09-223A.html
http://www.microsoft.com/technet/security/advisory/973472.mspx
http://isc.sans.org/diary.html?storyid=6778
http://blogs.technet.com/msrc/archive/2009/07/13/microsoft-security-advisory-973472-released.aspx