Lord Julus
29a [2]
February 1998
Before the heuristic analysers and the code emulators appeared on the market the usual encryption methods worked pretty good. And I do not speak only about viruses. I also reffer to the methods used for protecting software and data. Code emulators are able to crack your protections in a matter of minutes. That's when the ideea of polymorphism arose. A coder from Bulgaria passing by the nickname of Dark Avenger who wrote a lot of destructive viruses (including an antivirus against two of his viruses who unleashed a third virus) came with this ideea when his MtE (Mutation Engine) appeared. What polymorphism is really all about is creating self decrypting code, able to create each and every time a different decryptor containing both decrypting code and also junk instruction designed to make debugging and emultating harder.
As this article is not designed to explain why is this needed or make a pro statement for polymorphism I will get directly to facts.