Hickey created a malicious, macro-based Word document on his own computer that when opened would allow him to carry out a reflective DLL injection attack, allowing him to bypass the app store restrictions by injecting code into an existing, authorized process. In this case, Word was opened with administrative privileges through Windows' Task Manager, a straightforward process given the offline user account by default has administrative privileges. (Hickey said that process could also be automated with a larger, more detailed macro, if he had more time.)
But given the dangers associated with macros, Word's "protected view" blocks macros from running when a file is downloaded from the internet or received as an email attachment. To get around that restriction, Hickey downloaded the malicious Word document he built from a network share, which Windows considers a trusted location, giving him permission to run the macro, so long as he enabled it from a warning bar at the top of the screen. The document could easily point an arrow to the bar, telling the user to disable protected mode to see the contents of the document -- a common social engineering technique used in macro-based ransomware. (If he had physical access to the computer, he could have also run the file from a USB stick, but he would have to manually unblock the file from the file's properties menu -- as easy as clicking a checkbox.)
