Microsoft issued a patch Wednesday for a critical vulnerability in most versions of Windows that gives attackers remote control of a user's machine though Internet Explorer. But if the results of a new survey are any guide, most users won't install it.

The bug is a buffer overflow in an HTML conversion library used by a number of Windows programs, including Internet Explorer, and by extension Outlook and Outlook Express. To exploit it, an attacker tricks a victim into visiting a specially-crafted malicious Web page, or -- a more likely approach -- sends an Outlook user an HTML-formatted e-mail with the attack code embedded within.

A Russian hacker called "Digital Scream" reported the hole over Bugtraq on June 22nd, and other security researchers subsequently analyzed the vulnerability and produced a proof-of-concept exploit. With no advance warning, it took Microsoft seventeen days to release a patch -- not a unreasonable amount of time given the complexity of the problem, says Marc Maiffret, a founder of California-based security vendor eEye. "Since it is a component that is shared, and is not just used within Internet Explorer, it's a lot harder to test that the patch works with everything."

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