19.1. Understanding How VBA Implements Security
Macros and user forms contain computer programs, albeit usually rather small ones. But because macros like any other computer program can access the user's hard drive and manipulate other sensitive areas of the computer, macros can do damage.
Office 2007 and Vista include a variety of security features designed to protect the user from malicious code — macro, virus, Trojan horse, or whatever. But some security features are specific to Office documents and the macros and user forms they can contain.
Note that an evil macro can do its damage automatically; it's not necessary for the user to deliberately launch it from the Macros dialog box, or from within the Visual Basic Editor. Some specially named ...