Dr. Vesselin Bontchev FRISK Software International
Katrin Tocheva F-Secure Corporation
In an attempt to make their viruses more difficult to detect, virus authors are resorting to increasingly more sophisticated polymorphic mechanisms. This trend is only likely to continue in the future. In this paper we attempt to describe and classify the different polymorphic mechanisms used by the macro and script viruses so far, the kinds of technological advance they require from the anti-virus programs, and the likely future trends of polymorphic virus development.