W97M/Ethan
W97M/Ethan is a Word macro virus designed to infect Word 97. W97M/Ethan consists of a single macro less than 50 lines long. W97M/Ethan infects Word's NORMAL.DOT template and documents by inserting its code to a module in the document. W97M/Ethan uses an effective way to hide its code. By using special WordBasic operators W97M/Ethan installs its module into Word classes. The virus code is appended as a native Word component. As a result W97M/Ethan is not visible in the Tools/Macro menu.
It's good to know how and where the viruses attack the system. Just gives an extra insight of what goes inside the operating system.