Microsoft on Tuesday issued an “out-of-cycle” software patch to help stem the spread of a computer virus that was exploiting a newly revealed vulnerability in Internet Explorer.

The problem is a newly revealed vulnerability in IE goes back to the inception of IE. The report suggests the problem goes back to Windows 2000, but that is only because MS stopped supporting versions prior to that.

The as-of-yet unnamed “Trojan horse” virus takes advantage of a flaw in the “.ani” file format, which some Web sites use to change the mouse cursor into an hourglass while a program works, or into a dancing animal or other animation on specially designed Web sites.

The flaw was only publicly revealed last week, but by Friday virus writers were writing malware to exploit it, prompting one third-party security company to issue its own patch, and others to warn PC users not to use Internet Explorer.

Wha Happen?

Just another feather in the Micro$oft cap.