As files were shared around, more and more computers were infected. As well as documents, it could infect the preferences file and after that, any Word document you opened up on that same computer. It executed only within Microsoft Word but the macro language is the same across Windows and Mac computers so it ran just fine. Someone managed to bring a Word macro virus into the system. We were essentially a government contractor and, as such, nearly all our money came from sending Microsoft Word documents to the government to document what we had done and what we should be paid for.
Back in 2003, I was working in tech support for a Mac-based organisation.