This exploit uses the users’ common sense against themselves.
Security researchers at Cisco’s Talos threat research group have discovered one such attack campaign spreading malware-equipped Microsoft Word documents that perform code execution on the targeted device without requiring Macros enabled or memory corruption.
This Macro-less code execution in MSWord technique, described in detail on Monday by a pair of security researchers from Sensepost, Etienne Stalmans and Saif El-Sherei, which leverages a built-in feature of MS Office, called Dynamic Data Exchange (DDE), to perform code execution.
Dynamic Data Exchange (DDE) protocol is one of the several methods that Microsoft allows two running applications to share the same data. The protocol can be used by applications for one-time data transfers and for continuous exchanges in which apps send updates to one another as new data becomes available.
Source: MS Office Built-in Feature Allows Malware Execution Without Macros Enabled