We saw this last month, too, and it caused some big problems. If you receive an email claiming to be a Microsoft Security Alert, it isn’t.

Here is the main part of this story:

The e-mail messages claim to describe a “Cumulative Security Update for Internet Explorer” that fixes a critical security flaw in the browser. It comes with a link entitled “Download this update.”

When users click on this link, they are taken to a server that attempts to install malicious software known as Trojan-Downloader.Win32.Agent.avk.

PC World describes it here