Editing Microsoft Word (section)

===Macros===
A [[Macro (computer science)|macro]] is a rule of pattern that specifies how a certain input sequence (often a sequence of characters) should be mapped to an output sequence according to a defined process. Frequently used or repetitive sequences of keystrokes and mouse movements can be automated. Like other [[Microsoft Office]] documents, Word files can include advanced macros and even embedded programs. The language was originally [[WordBasic]], but changed to [[Visual Basic for Applications]] as of Word 97.

This extensive functionality can also be used to run and propagate [[Computer virus|viruses]] in documents. The tendency for people to exchange Word documents via email, [[USB flash drive]]s, and [[floppy disk]]s made this an especially attractive vector in 1999. A prominent example was the [[Melissa virus]], but countless others have existed.

These macro viruses were the only known cross-platform threats between Windows and Macintosh computers and they were the only infection vectors to affect any [[macOS]] system up until the advent of [[Zlob trojan|video codec trojans]] in 2007.{{citation needed|date=June 2021}} Microsoft released patches for Word X and Word 2004 that effectively eliminated the macro problem on the Mac by 2006.

Word's macro security setting, which regulates when macros may execute, can be adjusted by the user, but in the most recent versions of Word, it is set to HIGH by default, generally reducing the risk from macro-based viruses, which have become uncommon.