How to Own the Internet in Your Spare Time

The ability of attackers to rapidly gain control of vast numbers of Internet hosts poses an immense risk to the overall security of the Internet. Once subverted, these hosts can not only be used to launch massive denial of service floods, but also to steal or corrupt great quantities of sensitive information, and confuse and disrupt use of the network in more subtle ways.

We present an analysis of the magnitude of the threat. We begin with a mathematical model derived from empirical data of the spread of Code Red I in July, 2001. We discuss techniques subsequently employed for achieving greater virulence by Code Red II and Nimda. In this context, we develop and evaluate several new, highly virulent possible techniques: hit-list scanning (which creates a Warhol worm), permutation scanning (which enables self-coordinating scanning), and use of Internet-sized hit-lists (which creates a flash worm).

We then turn to the to the threat of surreptitious worms that spread more slowly but in a much harder to detect ``contagion'' fashion. We demonstrate that such a worm today could arguably subvert upwards of 10,000,000 Internet hosts. We also consider robust mechanisms by which attackers can control and update deployed worms.

In conclusion, we argue for the pressing need to develop a ``Center for Disease Control'' analog for virus- and worm-based threats to national cybersecurity, and sketch some of the components that would go into such a Center.