If you ever want to get some nightmares
Look up "OLE for process control". It's an "open standard" for industrial process control. To get the specifications you need to be a member. Membership starts at $1500 a year. Documents are in PDF (at least) but the provided videos are in strange early 1990s codecs.
Of course the standard is based on DCOM which is an obsolete Windows technology. (A new technology based on TCP/IP is being developed now called OPC UA)
So seriously I doubt they would have needed to exploit Word. Someone who spends a lot of money on such system probably doesn't understand the slightest bit of security. You could most likely just have send them a greeting card in an encrypted ZIP file.