as it appeared in the August 31, 2007 edition of ACM TechNews.
The treatment prescribed for computer worms is for system administrators to patch systems that will most likely limit an outbreak because they usually cannot fix all system vulnerabilities at the same time, while mutating worms are designed to exploit multiple vulnerabilities and continuously change infection tactics. Determining which computers should be initially patched in a mutating worm attack scenario is a problem that has been studied mathematically by Microsoft Research theoretical computer scientist Jennifer Tour Chayes. She suggests that the most highly connected systems should be patched first, irrespective of their proximity to other compromised systems. Chayes' research followed the assumption that even patched systems remain vulnerable to new attacks by the same worm. Through experimentation, she concluded that distributing patches to the most highly connected nodes in her network model, regardless of whether the nodes connecting them were also infected, brings the epidemic under control with far fewer patches than were required in an earlier strategy based on system administrators' typical response methodology. Chayes' findings are sobering, not just with respect to network security, but also to public health. For example, failure to adopt intelligent vaccine distribution could lead to situations in which outbreaks of new human viruses reach epidemic proportions. Click Here to View Full Article
