Online media company Revision3 says that it is the victim of a cyberattack launched by MediaDefender, a company that fights illegal peer-to-peer distribution of media on behalf of major entertainment companies.

Revision3, the host of Internet shows such as Diggnation, was inaccessible over the weekend. Company CEO Jim Louderback blames the outage on a denial-of-service attack initiated by MediaDefender.

In a blog post, Louderback explains that with a bit of network sleuthing, his IT staff discovered the source of the attack.

"But instead of some shadowy underground criminal syndicate, the packets were coming from right in our home state of California," he wrote. "In fact, we traced the vast majority of those packets to a public company called ARTISTdirect. Once we were able to get their Internet provider on the line, they verified that yes, indeed, that Internet address belonged to a subsidiary of ARTISTdirect, called MediaDefender."

MediaDefender did not return a call seeking comment.

To verify his claim, Louderback has posted a link to a file containing packet trace data derived from Revision3's log files.

Revision3 uses BitTorrent, a popular peer-to-peer protocol, to efficiently distribute its content. MediaDefender, Louderback notes, gets paid to disrupt peer-to-peer networks by injecting fake media files.

Because BitTorrent is popular among copyright scofflaws -- that's BitTorrent the protocol, which is distinct from BitTorrent the company -- some ISPs throttle BitTorrent packets as a way to manage network traffic volume and, presumably, to curry favor with copyright owners.

MediaDefender executives "willingly admitted to abusing Revision3's network, over a period of months, by injecting a broad array of torrents into our tracking server," Louderback said.

Louderback offered this interpretation of the attack: "Media Defender was abusing one of Revision3's servers for their own purposes -- quite without our approval," he wrote. "When we closed off their backdoor access, MediaDefender's servers freaked out, and went into attack mode -- much like how a petulant toddler will throw an epic tantrum if you take away an ill-gotten Oreo."

While it may be that the attack was the result of unforeseen consequences arising from MediaDefender's unauthorized use of a security hole at Revision3, Louderback isn't ready to dismiss the incident. He says that the FBI is investigating, and he is critical of MediaDefender's vigilante approach to fighting copyright piracy.

"In my opinion, MediaDefender practices risky business, and needs to overhaul how it operates," Louderback wrote. "Because in this country, as far as I know, we're still innocent until proven guilty -- not drawn, quartered and executed simply because someone thinks you're an outlaw."