This threat advisory contains information about the exploit currently being used in the wild for the MS Office DDE feature. DDE stands for Dynamic Data Exchange and is a feature that allow Office applications to talk to each other and exchange data. Malicious actors are using this feature to execute external applications without use of a macro. This exploit is currently being used in the wild to execute Powershell in order to download more malware.
For details, see Knowledge Base document PD27325 at https://kc.mcafee.com/corporate/index?page=content&id=PD27325