The Slammer computer worm that has swept the world's computers since Saturday could easily have had an even worse impact, according to the researcher who uncovered the software bug it exploits. The worm infected hundreds of thousands of computers, choking network bandwidth and slowing the internet as it multiplied. It surged across Italy on Tuesday, knocking out cash machines and severely disrupting the nation's 14,000 post offices. The worm spreads by broadcasting messages across networks in a general form known as UDP - but many computer firewalls are set up to block these. However, David Litchfield, discoverer of the weakness that Slammer targets, says it would have been simple to design the worm to identify itself as a specific type of UDP traffic, that slips through most firewalls. http://www.newscientist.com/news/news.jsp?id=ns99993332
