Malware, a word created by the contraction of malicious and software, describes a category of software created for malicious purposes. Examples of malware have been present in the digital world for at least twenty five years.1 As with any other species, malware had to go through an evolutionary process to survive the changes that have occurred in its lifetime: this evolutionary shift has been all the more dramatic for being compressed into the last quarter of a century. The first “families” of malware were created by computer hobbyists to show off their own programming skills. The virus-writing scene has changed greatly, though, and profit is now the primary driving force behind nearly all malware creation. The huge sums of money that can be made by creating and exploiting malware are a great incentive to malware authors to improve their techniques. From our analysis of past and present trends, we predict that malware programming techniques will continue to increase in sophistication: and that we will have to deal with more malware that exploits software security flaws and uses “defensive programming” aimed at reducing its own susceptibility to detection and removal by security software.

In this article, we will present an overview of the evolution of malicious software*. We will focus on the objectives of this type of program to provide evidence for our predictions as to how they will evolve in the years to come.