Microsoft Patches PowerPoint Flaws, But Not For Mac

Microsoft's monthly Patch Tuesday brings only one security bulletin for May, MS09-017, which fixes 14 distinct vulnerabilities in Microsoft Office PowerPoint.

Early last month, Microsoft issued a security advisory about a PowerPoint vulnerability that was being exploited in the wild. But the company didn't have time to include a fix later that month in its April patch release.

Time is also an issue in this month's patch. Microsoft said that its PowerPoint patch fixes the holes in the Windows version of the software but not the Mac version.

"The Mac version of Office is affected but the packages are still in testing so we are 'going live' today with Windows packages only," Microsoft engineer Jonathan Ness said in a post on the Microsoft Security Research & Defense blog. "We normally do not update one supported platform before another, but given this situation of a package available for an entire product line that protects the vast majority of customers at risk within the predictable release cycle, we made a decision to go early with the Windows packages."

Ness said that Microsoft will revise its security bulletin when the Mac fix has be adequately tested. Mac users ought not to worry, however, since none of the malware samples collected by Microsoft attempts to exploit any PowerPoint vulnerability on the Mac.

One of the 14 bulletins is rated "critical" and the rest are rated "important." All of them could lead to remote code execution.

According to Ness, the MS09-017 security update "dramatically reduces the attack surface" of PowerPoint by removing support for an old PowerPoint 4 converter (PP4X322.DLL). It's no longer an option to create "PP40" files in Office XP, Office 2003, and Office 2007.

While some security vendors welcome the light workload in Microsoft's May patch cycle, Paul Henry, security and forensic analyst for Lumension, advises against relaxing.

"[I]t is important for IT admins to understand that this Patch Tuesday isn’t just about patching Microsoft’s single patch but rather fixing other security flaws that are non-MS related in order to stay current and patched," he said in a blog post Monday, pointing to almost 50 recently reported vulnerabilities in popular software from the likes of Adobe, Google, Firefox, and Symantec.

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