This latest attack isn't the newest or most severe Second Life has experienced. In October 2006, a glut of attacks followed a vague "terrorist" threat uttered by self-replicating objects. In April 2006, three major attacks took place. Almost a year ago today, Linden Lab blocked a DoS attack by deploying a giant virtual firewall in-world, but I don't think that method is still used. Linden Lab had suggested earlier this year it would bring DoS attackers to the attention of law-enforcement agencies, but the results (if any) have not been publicized.