Even though they can be extremely hard to detect, most of the today's products are able to deal with them relatively easily. These are the scanners that survived the DOS polymorphic days. For some of the scanners DOS polymorphic viruses meant the 'end of days'. Other scanners died with the macro virus problem. For most products the next challenge to take is 32-bit metamorphism.
Metamorphic viruses are nothing new.
We saw them in the DOS days though some of them, like ACG, already used 32-bit instructions. The next step is 32-bit metamorphism under Windows environments. Virus writers have already taken the first step in that direction. In this paper the authors will examine metamorphic engines to provide a better general understanding of the problem that we are facing. The authors also provide detection examples of some of the metamorphic viruses.