Microsoft patches IE, admits it knew of bug last August

Emergency patch fixes eight flaws in Microsoft's browser -- seven rated 'critical' -- including the vulnerability used to attack Google and others

As Microsoft patched the Internet Explorer (IE) vulnerability that was used to break into Google's network, it also acknowledged that it had known of the bug since August 2009, when an Israeli security company reported the flaw.

"As part of [our] investigation, we also determined that the vulnerability was the same as a vulnerability responsibly reported to us and confirmed in early September," said Jerry Bryant, a senior program manager with the Microsoft Security Response Center, on the MSRC blog today.

[ Learn how to secure your systems with Roger Grimes' Security Adviser blog and Security Central newsletter, both from InfoWorld.  | Grimes also explains how to stop data leaks in an enlightening 30-minute webcast, Data Loss Prevention, which covers the tools and techniques used by experienced security pros. ]

The MS10-002 bulletin that accompanied the IE update credited Meron Sellem of BugSec for reporting the bug that has raised a ruckus since Google accused Chinese cybercriminals with hacking its network.

Sellem said that BugSec, a penetration testing and security firm in Rishon LeZion, Israel, reported the vulnerability to Microsoft on Aug. 26, not in September as Microsoft indicated. And he was critical of Microsoft for taking this long to release a patch. "I think yes, it took too long," he said. "But Microsoft is a big organization and we don't know how much time it takes them. We asked them why it was taking such a long time, and they said it was because of the testing they had to do."

Andrew Storms, director of security operations at nCircle Network Security, said the fact that Microsoft knew of the browser's vulnerability months before it crafted a patch -- months before Chinese criminals used the flaw -- shouldn't come as a shock.

"It's pretty par for the course, really," said Storms. "We know that patches sit for a good month or so in QA [quality assurance] at Microsoft. So if it was reported to Microsoft in September, it might not have been added to the [patch] cycle until October, and the code not written until November. A February release isn't crazy then."

Storms refused to use hindsight to say that Microsoft was tardy to the party. "Unless you have real evidence that it's being used, you can't take that into account when you prioritize patches," he argued. "You take into account the skill level necessary to exploit it. But if it's responsibly disclosed, you have to assume that it's not going to release [publicly]. And without partners saying that they're seeing signs of it being exploited, Microsoft probably thought they could just roll it into their normal IE release cycle."

Microsoft last patched IE in December 2009, and on average, updated its browser every two months.

It didn't surprise Sellem that others found the vulnerability, then decided to use it maliciously. "We found this vulnerability very easily," said Sellem, "and we didn't think it would be hard for others to find." BugSec spent about two weeks researching IE before it discovered the flaw, Sellem added.

"There have certainly been cases when multiple people have reported the same bug, so it's not hard to fathom that more than one could have found this at around the same time," said Storms.

Besides the patch for the vulnerability used to attack Google and others, Microsoft also patched seven other bugs in IE in Thursday's update. Of the eight flaws fixed, seven were rated "critical" by Microsoft, the highest threat ranking in its four-step scoring system.

"Actually, we're getting February's IE update early," said Storms, referring to Microsoft's admission that this "out-of-band" was previously planned for Feb. 9, the company's next regularly-scheduled Patch Tuesday.

"Earlier, I was a bit surprised how quickly they said they would patch [the Google] bug, but now it all makes sense," said Storms. "These were already in QA -- they would have had to be if there were going to release them in February -- so it's no surprise that they were able to release a fix in two weeks time."

Microsoft's Bryant said that the company was alerted that hackers were actively using the IE vulnerability only on Jan. 11. Google, however, said it first uncovered evidence of attacks on its network in mid-December 2009, and began reaching out to other companies that may have been victimized shortly after.

No matter when this patch would have hit, Google attack or not, it would have been a big deal. "If this had come out in February, it would have been the most important patch of the day," Storms argued. "It's client side, it's IE, it has a good handful of remote code vulnerabilities, so this would have been the No. 1 to go out and patch immediately." In fact, Storms expects that researchers, both legitimate and criminal, will be digging into the cumulative update, looking for hints that will lead them to other exploits.

"So I guess we can be thankful that we're getting it early," said Storms.

The IE security update can be downloaded and installed via the Microsoft Update and Windows Update services, as well as through Windows Server Update Services.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld . Follow Gregg on Twitter at @gkeizer, send e-mail to or subscribe to Gregg's RSS feed.

This story, "Microsoft patches IE, admits it knew of bug last August" was originally published by Computerworld.

Copyright © 2010 IDG Communications, Inc.