New Vulnerability Discovered In Microsoft Excel

Here's what we know: In order for this attack to be carried out, a user must first open a malicious Excel document that is sent as an email attachment or otherwise provided to them by an attacker. (note that opening it out of email will prompt you to be careful about opening the attachment) So remember to be very careful opening unsolicited attachments from both known and unknown sources...

We're also actively sharing that information with our Microsoft Security Response Alliance partners so that their detection can be up to date to detect and remove attacks. We've got the Office team engaged of course and they are hard at work investigating the vulnerability.