Excel 0-Day ExploitedFebruary 24, 2009 – 5:32 AM
Symantec is reporting that Trojan.Mdropper.AC is exploiting an unpatched vulnerability in Excel 2007. Earlier versions of Excel may also be vulnerable.
The vulnerability is described as a “Boundary Condition Error” and can result in remote code execution, but that’s it for details for now. The research is obviously in its early stages, and the fact that Symantec calls Trojan.Mdropper.AC a “Risk Level 1: Very Low” threat indicates that it was used in a targeted attack. So it’s not likely that this will be widespread any time soon, but eventually it may be.
You already had ample reason to be suspicious of unsolicited Excel files, but take this as added warning against opening such documents unless you know what they are.