At McAfee, we have put significant efforts in hunting attacks such as advanced persistent threats and “zero days.” Yesterday, we observed suspicious activities from some samples. After quick but in-depth research, this morning we have confirmed these samples are exploiting a vulnerability in Microsoft Windows and Office that is not yet patched.

https://securingtomorrow.mcafee.com/mcafee-labs/critical-office-zero-day-attacks-detected-wild/