The websites of the Motion Picture Association of America, the Recording Industry Association of America and an Indian anti-pirate organisation were crippled under a spate of coordinated retaliatory attacks.
The distributed denial-of-service (DDoS) attacks were part of Operation Payback, launched by the Anonymous collective and users on the infamous online forum 4chan, which targeted and crippled the organisations' websites after it was reported the companies had previously attacked pirate websites using the same techniques.
"We target the bastard group that has thus far led this charge against our websites, like The Pirate Bay," said a post captured by TorrentFreak. "We have the manpower, we have the botnets, it's time we do to them what they keep doing to us."
For more on this story, see Pirate 'payback' attacks target web hitmen on ZDNet Australia.