Zero-Day IE Exploit To Get Out-of-Cycle Patch

"Critical" out-of-cycle patch for Internet Explorer

After tackling the most disclosed vulnerabilities in the history of Patch Tuesday last week, Microsoft will now end 2008 with a "critical" out-of-cycle patch for Internet Explorer, according to an advance notification issued Tuesday for a new security update slated for release on Dec. 17.

According to Microsoft, the new patch will address an increasingly pervasive vulnerability that allows remote code execution in numerous versions of IE.

The new patch will affect IE 5.01, IE 6, and all versions of IE 7 sitting on Windows 2000 Service Pack 4, Windows XP and XP Professional, Vista, and Windows Server 2003 and 2008.

The emergency fix is a direct response to a zero-day IE 7 bug found in the wild last week, one day after Microsoft released what appeared to be a comprehensive IE patch addressing four separately reported private vulnerabilities.

Ben Greenbaum, senior research manager of Symantec Security Response, said that while the timing isn't ideal, Microsoft responded properly to what was becoming a growing security threat as the attacks widened in both geographical and technological scope.

"Nobody likes to do a patching of this importance and size, especially in a large IT environment, at a time when everyone's either gone or getting ready for the holidays," Greenbaum said. "It's one of those things, though, where you could be coming back to a big mess in January. From our standpoint, we would recommend an immediate patch in the event that [Microsoft] releases the update on Wednesday."

For its part, Microsoft maintained on Tuesday that it was aware only of attacks that attempt to use the vulnerability against IE 7. Nonetheless, the company said it "encourages customers to test and deploy this update as soon as possible."

The fix is vital for Microsoft as IE is currently used by 69 percent of the world's surfers and is arguably one of the company's most recognizable brands outside of the Office suite.

Shavlik Technologies CTO Eric Schultze said this out-of-cycle rollout constitutes an "all hands on deck" response from Microsoft.

He added, "Specifically, attackers were loading the exploit on legitimate Web sites so that even users who visit only non-nefarious Web sites might also get infected. Based on this level of data, it's my belief that Microsoft decided the issue warranted an out-of-band patch release."

-- Jabulani Leffall

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