Wormable system vulnerabilities continue to be identified and so fast spreading network worms continue to pose a threat to the Internet infrastructure due to their increased virulence, speed and sophistication in successive Internet-wide outbreaks. The cost of a single worm outbreak has been estimated to be as high as US $2.6 billion. In this paper, we report the empirical analysis of distributed worm detection and prevention countermeasure Rate Limiting + Leap Ahead (RL+LA) by using Pseudo-Witty worm with real outbreak characteristics of Witty worm. RL+LA, is a distributed automated worm detection and containment scheme that is based on the correlation of Domain Name System (DNS) queries and the destination IP address of outgoing TCP SYN a...