McAfee [MFE] has discovered the first known zero-day exploit of Microsoft [MSFT] Office’s .docx file format, the company said this week in a quarterly threat report. McAfee began working with Microsoft in November 2013 after spotting the exploit in the Middle East and Asia being used to steal sensitive data. The malware, CVE-2013-3906, locates and exfiltrates specific file types once it enters a user’s environment. The attacks were targeted at high-level institutions, including the Pakistani military, McAfee said. The company…