Microsoft releases out-of-cycle patch for IE flaw

September 18, 2013 // 9:08 a.m.

Tags: #ie #insecurity #internet-explorer #microsoft #msie #patch-tuesday #security #software #vulnerability #web #web-browser

Microsoft's bad September continues to grow worse, with the company being forced to issue an out-of-cycle patch for a zero-day vulnerability in its Internet Explorer web browser.

Microsoft's September got off to a bad start when the company issued a raft of faulty updates as part of its monthly Patch Tuesday release cycle. While the issues have now been resolved, the company was forced to remove and re-release a total of ten patches - making it the worst Patch Tuesday in a six-month run that has seen only a single month go by without a show-stopping fault resulting in patches being reissued following customer complaints.

Today's admission from the company isn't going to do much to salve its public image, either: Microsoft has confirmed that a flaw in its Internet Explorer web browser is being actively exploited in targeted attacks, and considers the issue serious enough to release an out-of-cycle fix ahead of next month's Patch Tuesday.

The update, which is only available for manual installation and will not be published through Windows Update, is a work-around rather than a true fix for a pretty serious flaw in Microsoft's MSHTML Shim component - which had already been targeted in prior attacks at the start of the year. 'This issue could allow remote code execution if an affected system browses to a website containing malicious content directed towards the specific browser type,' explained Microsoft's Dustin Childs in an alert to the security community.

'This would typically occur when an attacker compromises the security of trusted websites regularly frequented, or convinces someone to click on a link in an email or instant message. Running modern versions of Internet Explorer ensures that customers receive the benefit of additional security features that can help prevent successful attacks,' he added - but while the current targeted attacks are only being pointed at the outdated Internet Explorer 8 and Internet Explorer 9 releases, it is thought the flaw could exist across all versions of IE.

For those who use Internet Explorer, Microsoft's advice is to install the out-of-cycle Fix-It patch to work around the issue until a proper solution can be found. The patch applies to all version of Internet Explorer from IE 6 through to the latest IE 11, although is only designed to resolve the issue with the 32-bit version - the 64-bit version, it would seem, being better protected against the vulnerability.

With Microsoft's recent track record for patches causing problems worse than they solve, however, users would be well advised to test the patch on a virtual machine or similar throw-away system before rolling it out on a wider scale.

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