We will present our analysis of the surprisingly strong impact of recent Microsoft worms (such as Code Red II and Nimda) on the stability of the global routing system. Analysis of the on-line BGP message archives from the RIPE-NCC Routing Information Service, and of the worm scanning and infection spread datasets shows strong correlations between worm propagation periods and very long-lasting BGP "update storms."

We will also discuss preliminary results concerning the populations of unstable routes, unreachable networks, and the mechanisms by which the worm traffic may be destabilizing the BGP routing system.