Microsoft Scrambles to Fix Zero-Day Flaw in OLE

A Sandworm variant gets a "Fix it" update, but not yet a full patch. The flaw abuses the same OLE technology that enables the Sandworm bug.

Microsoft Zero Day Flaw

Microsoft is once again scrambling to contain a zero-day vulnerability in a software component that it has recently patched.

Microsoft's Oct. 4 Patch Tuesday update included fixes for 24 Common Vulnerabilities and Exposures (CVEs), including CVE-2014-4114, also known as Sandworm. On Oct. 21, Microsoft first began to warn its users about a flaw identified as CVE-2014-6352, which abuses the same Microsoft Object Linking and Embedding (OLE) technology that enables the Sandworm vulnerability.

OLE is Microsoft's Object Linking and Embedding technology that enables content to be linked inside of documents.

"In an email attack scenario, an attacker could exploit the vulnerability by sending a specially crafted file to the user," Microsoft warns in its advisory. "All Microsoft Office file types as well as many other third-party file types could contain a malicious OLE object."

Security firm Symantec is warning that attackers are already exploiting the new OLE vulnerability. "While the original vulnerability [CVE-2014-4114] involved embedded OLE files linking to external files, the newer vulnerability [CVE-2014-6352] relates to OLE files that have the executable payloads embedded within them," Symantec warned in a blog post.

Microsoft has not yet issued a full patch for the CVE-2014-6352 flaw, though it has issued a "Fix it" solution to help users mitigate the risk.

A "Fix-it" is basically like a "band-aid" to stop immediate bleeding; in contrast, an emergency patch involves surgery to fix the problem, Rahul Kashyap, chief security architect and head of research at Bromium, told eWEEK.

Kashyap added that Fix-it solutions are typically minimally tested by Microsoft as these come out rather quickly. The Fix it updates also need to be manually implemented and aren't sent out via the automatic updater mechanism from Microsoft.

"Generally, Microsoft looks at various aspects like the likelihood of exploitability of the vulnerability, the intrusive nature of the patch and how widely it impacts users before deciding if an out-of-band patch is necessary," Kashyap said.

OLE hasn't necessarily been a prime target for hackers and security researchers in recent years, but that could change. Kashyap commented that it's difficult to know if more OLE vulnerabilities will be uncovered in the coming weeks, as it depends on how many people poke around with OLE after this episode.

"OLE, in general, is a complex feature with a lot of legacy code, so finding more issues cannot be totally ruled out," Kashyap said.

Sean Michael Kerner is a senior editor at eWEEK and Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.