Security researchers called out the missing fix for the Internet Explorer zero-day flaw in January's Patch Tuesday. Now, Microsoft is moving to deal with the security issue in its Web browser in an out-of-band patch.
Dustin Childs, group manager for Microsoft Trustworthy Computing, announced the fix on the Microsoft Security Response Center blog. The patch was released Monday to fix the issue described in Security Advisory 2794220.
"While we have still seen only a limited number of customers affected by the issue, the potential exists that more customers could be affected in the future," Childs said. "The bulletin has a severity rating of critical, and it addresses CVE-2012-4792. Internet Explorer 9-10 are not affected by this issue and as always, we encourage customers to upgrade to the latest browser version."
Exclusive to the Browser?
Paul Henry, security and forensic analyst at Lumension, applauded Microsoft for its fast move to issue a fix-it last week for issues with Internet Explorer. But, he told us, it's interesting to note that nothing in these bulletins seem to directly affect IE. On the other hand, even with the formal patch release on Monday, he suggested the fix-it may have been a necessary precursor to the Monday out-of-band patch.
"Microsoft often fixes one thing to address another, so it's possible that they are correcting the issue with IE at the operating system level with one of the patches," Henry said. "If the browser is just a path to an underlying vulnerability in the operating system, then this issue will likely be fixed by one of the patches. If the vulnerability is exclusive to the browser, on the other hand, then this is still something to watch out for."
Henry also noted that the exploit is being used in the wild and needs to be addressed immediately. Microsoft's Childs also recommended that IT install the update as soon as possible. If you applied the fix-it released in Security Advisory 2794220, he said, you won't need to uninstall it before applying the security update.
Previous Versions Threatened
Mark Elliott, executive vice president of products at Quarri Technologies, told us this IE vulnerability poses a critical threat to users of previous versions of the browser, which represent a number of Microsoft users.
"While a quick fix was made available for this bug, there is still a high probability that many end users did not perform the necessary mitigation steps to fix the vulnerability. While the availability of a patch is a positive development, it is still likely that a large portion of IE users will remain unprotected," he said. (continued...)