Security Experts:

Microsoft's Internet Explorer Fix It Measure Bypassed

A company that deals vulnerability intelligence and pays for research has said they were able to bypass the"Fix It" measure offered by Microsoft recently. Microsoft’s Fix It solution was offered in order to address Watering hole attacks targeting a zero-day vulnerability in Redmond’s Web browser.

According to Exodus Intelligence, after a day of reversing the Fix It code, they were able to infect a ‘patched’ system due to bypassing Microsoft’s code. The full details of their work are only available to those who pay for an intelligence feed, but Microsoft has been informed.

“After posting our analysis of the current 0day in Internet Explorer which was used in a “watering hole” style attack hosted on the Council for Foreign Relations website, we decided to take a look at the Fix It patch made available by Microsoft to address the vulnerability. After less than a day of reverse engineering, we found that we were able to bypass the fix and compromise a fully-patched system with a variation of the exploit we developed earlier this week,” an Exodus blog post states.  

Last week, Microsoft confirmed the existence of zero-day flaw in Internet Explorer, and noted that there have been “limited” attacks. According to research from FireEye, the vulnerability in Internet Explorer is targeted by Adobe Flash. So far, malicious Flash files linked to this attack have been used to infect visitors to the Council on Foreign Relations’ website, two Chinese human rights websites, a newspaper in Hong Kong, and a Russian science domain.

On Friday, Symantec said these attacks had the calling card of the Elderwood gang, a group of cyber criminals who have used similar tactics in the past. SecurityWeek’s coverage of that story is here

Microsoft is patching an impressive number of issues this month, but based on Thursday’s preview, this latest Internet Explorer vulnerability isn’t one of them – and at least one person has managed to bypass the publically available mitigation.

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Steve Ragan is a security reporter and contributor for SecurityWeek. Prior to joining the journalism world in 2005, he spent 15 years as a freelance IT contractor focused on endpoint security and security training.