Most anti-piracy tools take one of two paths: they either target the server that's sharing the files (pulling videos off YouTube or taking down sites like The Pirate Bay) or they make it harder to find (delisting offshore sites that share infringing content). But leaked documents reveal a frightening line of attack that's currently being considered by the MPAA: What if you simply erased any record that the site was there in the first place?

A bold challenge to the basic engineering of the internet

To do that, the MPAA's lawyers would target the Domain Name System (DNS) that directs traffic across the internet. The tactic was first proposed as part of the Stop Online Piracy Act (SOPA) in 2011, but three years after the law failed in Congress, the MPAA has been looking for legal justification for the practice in existing law and working with ISPs like Comcast to examine how a system might work technically. If the system works, DNS-blocking could be the key to the MPAA's long-standing goal of blocking sites from delivering content to the US. At the same time, it represents a bold challenge to the basic engineering of the internet, threatening to break the very backbone of the web and drawing the industry into an increasingly nasty fight with Google.

The Domain Name System is a kind of phone book for the internet, translating URLs like http://www.theverge.com into IP addresses like 192.5.151.3. Given a URL string, your computer will turn to a DNS server (often run by a local ISP or a third party like Google) to find the IP address of the corresponding server. Much like the phone book, that function is usually treated as a simple an engineering task — but a memo commissioned by the MPAA this August sketches out a legal case for blocking infringing sites from the DNS records entirely, like wiping unsavory addresses out of the phone book. You could still type http://www.piratebay.se into your browser, but without a working DNS record, you wouldn't be able to find the site itself. If a takedown notice could blacklist a site from every available DNS provider, the URL would be effectively erased from the internet.

Without a friendly DNS provider, the URL would be effectively erased from the internet

No one's ever tried to issue a takedown notice like that, but this latest memo suggests the MPAA is looking into it as a potentially powerful new tool in the fight against piracy. "A takedown notice program, therefore, could threaten ISPs with potential secondary liability in the event that they do not cease connecting users to known infringing material through their own DNS servers," the letter reads. "While not making it impossible for users to reach pirate sites (i.e., a user could still use a third-party DNS server), it could make it substantially more complicated for casual infringers to reach pirate sites if their ISPs decline to assist in the routing of communications to those sites." The full document is embedded below.

"It could make it substantially more complicated for casual infringers to reach pirate sites"

That would give content owners a powerful new tool against piracy, but that power could be ripe for abuse. As critics pointed out in the SOPA debate, site-blocking measures could also be used by bad actors to knock a site offline with just a bogus copyright claim. DMCA notices have already drawn criticism for overly hasty or broadly applied blocks, and extending that power to DNS records would spread those problems across the web at large. Crucially, any takedown notices deployed under this scheme would simply invoke the threat of liability and further legal action, pressuring the DNS servers to delist the site without ever hearing the issue in court.

The MPAA’s legal argument centers on the claim that DNS records are working as an index or directory rather than simply routing data. If that argument holds, then the DNS links could be vulnerable to the same takedown notices used to strike torrent links from Google searches. The net effect would be similar to site-blocking, making it as easy to unplug a URL as it is to take down a YouTube video. It would also cast DNS providers as legally responsible for all the sites on the web, the same way YouTube is responsible for every video uploaded to its network. For many providers, simply managing the flood of notices might create a logistical nightmare.

The plan could create a kind of DNS black market, exposing users to untold security risks

There are still serious technical problems with the approach. Determined users would be able to get around the block by typing the IP address directly into their browsers, or by configuring their computers to use a DNS server that's not affected by the block. Standard circumvention tools like VPNs and Tor will also find it easy to get around the block. But the MPAA’s goal is primarily to deter and marginalize file-sharing, so forcing any would-be pirates to reconfigure their DNS setting might be enough. As one technical analysis notes, "notwithstanding the availability of these circumvention techniques, it does not appear that the majority of users are employing them to evade blocks of pirate sites."

But even if the result stops short of making a site completely inaccessible, it could still do real damage to the DNS system as it currently functions. The DNS system is already a contentious security issue, sometimes exploited by attackers to hijack websites, and any authentication measures like DNSSEC would quickly run into problems under the MPAA’s new scheme. If users flee standard DNS servers in search of pirate sites, DNS blocks could also create a kind of DNS black market, exposing piracy-seeking users to untold security risks.

Mostly, it represents one more time the fundamental architecture of the web has come under fire as part of an anti-piracy scheme. It's still unclear whether the plan would prove technically feasible or whether the legal arguments would survive in court, but the document suggests the MPAA hasn’t backed away from its goal of blocking any site that shares pirated content, and it isn’t afraid to leave systems like DNS as collateral damage. Even worse, while the rest of the web seems to have moved on from SOPA, the MPAA is still using it as a playbook.

Comms Act and DMCA Safe Harbor