This is a Microsoft Excel macro virus. Sofa spreads to Excel
spreadsheets once it has copied its virus code to the default
startup directory. It does this by creating a file called
Sofa contains these macros: Auto_Open, Auto_Range, Current_Open,
Sofa activates by checking the title bar text of Excel to read
Otherwise, the virus just spreads.
Sofa was found in the wild in USA in December 1996.
[Analysis: Mikko Hypponen, F-Secure]