It is certainly unlawful: it is trying actively to disrupt someone's service (a website but also possibly its entire business). There are also specific laws for

It is certainly unlawful: it is trying actively to disrupt someone's service (a website but also possibly its entire business). There are also specific laws for DoS[0]. [0]: http://en.wikipedia.org/wiki/Denial-of-service_attack#Legality http://en.wikipedia.org/wiki/Denial-of-service_attack#Legali...