Microsoft to fix IE8 zero-day flaw on Patch Tuesday

Microsoft’s May Patch Tuesday will include a fix for a recently discovered zero-day flaw in Internet Explorer 8 that has been used to attack several high-profile targets.

The company said it would fix 33 unique vulnerabilities in two critical bulletins and eight updates rated ‘important’, and has rushed out a patch for a hole that was first seen last week being used by hackers targeting US government workers.

“The Critical-rated bulletins address issues in Microsoft Windows and Internet Explorer,” said Dustin Childs, group manager for Microsoft Trustworthy Computing in a blog post.

“Of note, we are working to have the Internet Explorer Security Update address the issue described in Security Advisory 2847140, supplementing the currently available Fix it.”

The vulnerability allows attackers to run code on target machines, with the aim of extracting account details or confidential data.

The vulnerability had previously been addressed in a workaround yesterday, but given the way it was being exploited – with attacks reported on the US Department of Labor and European aerospace and nuclear researchers – the patch has been prioritised.

At least four of the patches require a restart, Microsoft said.

According to experts, the fix for the IE8 zero day weakness should top your to-do list.

“Bulletin 2 is for the recent IE8 zero-day and should be on the top of your list if you are on IE8, which, according to our BrowserCheck statistics, still accounts for about 43% of [IE] users,” said security firm Qualys.

“Bulletin 1 is also for IE and affects all versions from 6 to 10 on all Windows operating systems from XP to 8, and including RT. It includes the patches for the vulnerabilities discovered at the Pwn2Own competition at CanSecWest in March of this year.”