The Evolution of Viruses and Worms

Computer viruses and network worms have evolved through a continuous series of innovations, leading to the recent wave of fast-spreading and dangerous worms. A review of their historical development and recent outbreaks leads to a number of observations. First, while viruses were more common than worms initially, worms have become the predominant threat in recent years, coinciding with the growth of computer networking. Second, despite widespread use of firewalls and other network security equipment, worm outbreaks still occur and will likely continue to be a threat for the near future. Third, recent worms are appearing as a series of quick successive variants. Unlike the independent efforts of early viruses, these variants suggest an increasing level of coordination among worm creators. Fourth, recent worms have shown capabilities to spread faster and exploit more infection vectors. This trend implies a more urgent need for automated, coordinated protection measures. Finally, more dangerous payloads are becoming commonplace. This suggests that worm creators are using worms for other objectives than simply infection, such as data theft and setting up denial of service networks.