My advice: Patch this puppy, and don't worry about whether or not Microsoft should have published this update out of its normal monthly update cycle.Last week, right on Patch Tuesday, in fact, Microsoft learned of a zero-day vulnerability, and toward the end of the week, it was being widely exploited.

The first point is that more zero-days are being released on, or right after, Patch Tuesday. This is no doubt a tactic designed to maximize the shelf life of the exploit. I fully expect this trend to increase, especially as more software vendors publish software security updates on a standard schedule. I still think this practice reaps more benefit than harm: without it, there would be more zero-day attacks and we'd be patching our systems every week. That drains enterprise resources.

Second: Microsoft had to release this patch because the vulnerability was being exploited, and users could get attacked just by visiting a Web site -- even so-called trusted Web sites. It was getting nasty.

As was explained to Thomas Claburn in this story:

"The browser flaw had been disclosed roughly one week ago as a zero-day vulnerability, and active exploits have been around the Internet for that time frame as well," Qualys CTO Wolfgang Kandek said in an e-mailed statement. "The workarounds provided by Microsoft were very technical and quite cumbersome to implement, making it imperative for Microsoft to release a fix as quickly as possible."

That sums it up well. The workarounds were quite kludgey.

However, I have to take partial issue with this take from Roel Schouwenberg, senior antivirus researcher with Kaspersky Lab, Americas, on what this flaw's lack of wormability, and subsequent out-of-band patch, means:

"[That] shows that the wormability of a vulnerability is no longer a good indicator of the seriousness of a threat and that these Web-based threats are now much more dangerous than network worms," said Roel Schouwenberg, senior antivirus researcher for Kaspersky Lab, Americas, in an e-mailed statement.

I see his point, and actually agree that Web-based threats are both more prevalent and more dangerous (in many scenarios I can think of) than network worms. However, "worm ability" is still a strong indicator of the seriousness of a threat.

And we will see more Web-based worms in the future. Why? Because they're more profitable than network worms. The age of network worms died largely because there's more profit to develop exploits that can make a buck: not worms that essentially cause widespread denial-of-service situations.

Wormable or not. Whether Microsoft should have gone out-of-band with this one, or not. You need to patch MS08-078.

Eric Schultze, CTO at Shavlik Technologies, e-mailed me an interesting wager: "I'd bet you a cookie that many companies can't get it rolled out as quickly as Microsoft got it built."

I'll bet he's right.