BitTorrent watchdog MediaDefender is once again taking heat after it was accused of launching a pernicious attack that brought down a web-based distributor of legal video.

Jim Louderback, chief executive of Revision3, said in this blog post that the FBI is investigating the assault, which at points flooded his site with more than 8,000 SYN packets a second. The attack, which lasted through the Memorial Day weekend in the US, was enough to bring down the company's public facing website, its RSS server and its internal email system.

The packets began appearing on Saturday and were directed at port 20000, which happens to be the entry point for a BitTorrent tracking server Revision3 uses to distribute videos it has the legal rights to make available. They came primarily from machines that brazenly bore MediaDefender's IP address and didn't let up until sometime on Tuesday.

"Revision3 suffered measurable harm to its business due to that flood of packets, as the attacks on our legitimate and legal Torrent Tracking server spilled over into our entire internet infrastructure," Louderback wrote. "Thus we were unable to serve videos and advertising through much of the weekend."

Representatives of MediaDefender, which is a wholly owned subsidiary of publicly traded company ArtistDirect, didn't respond to phone calls and emails asking for comment.

But as you can imagine, Louderback was a bit more motivated to speak with officials there and finally got a hold of interim CEO Dimitry Villard and vice president of operations Ben Grodsky. According to Louderback, the former editor-in-chief for PC Magazine, they told him their computers had been injecting a "broad array of torrents" into Revision3's tracking server for months. The flood of SYN packets - the internet protocol equivalent of a "hi" that begins a face-to-face conversation - seems to have started once Revision3 closed the loophole that allowed MediaDefender's unauthorized action.

"MediaDefender's servers, at that point, initiated a flood of SYN packets attempting to reconnect to the files stored on our server," Louderback wrote. "And that torrential cascade of 'Hi's' brought down our network."

This is by no means the first time MediaDefender has been accused of thuggish behavior. In September, a slew of internal emails turned up on BitTorrent sites, of all places, and showed the company engaged in tactics including "infrastructural sabotage, denial of service attacks, hacking, and spamming." MediaDefender is funded by a broad array of record labels and movie studios.

Of course, some people may say Revision3 is little more than a site that offers second-rate videos, so where is the real harm in knocking it off line for a few days. Well, Louderback has anticipated that and offers this counterargument:

"What if MediaDefender discovers a tracker inside a hospital, fire department or 911 center? If it happened to us, it could happen to them too." ®