The Computer Fraud and Abuse Act (CFAA), a controversial anti-hacking law which bans “exceeding authorized access” on a computer system, was narrowed by the Supreme Court on Thursday in a 6-3 ruling. The court said the law shouldn’t cover people misusing systems they’re allowed to access — and that claiming otherwise would criminalize a “breathtaking amount” of everyday computer use.

The court case, Van Buren v. United States, concerns a former Georgia police officer named Nathan Van Buren. Van Buren accepted $5,000 in exchange for looking up a woman’s license plate in a police database. (The deal was actually an FBI sting operation, and the plate number was fictitious.) Because the exchange violated department rules, prosecutors said Van Buren had “exceeded access” to the system. Van Buren’s lawyers argued that whether or not he misused the database, he was authorized to access it — and therefore hadn’t violated anti-hacking laws.

The Supreme Court’s majority opinion, delivered by Justice Amy Coney Barrett, concurred. It backed a “gates-up-or-down” approach to authorization: accessing parts of a system that are specifically forbidden breaks CFAA rules, but simply accessing authorized areas in an unapproved way does not.

Barrett’s opinion noted that people routinely bend or break the rules of computers and web services. “The government’s interpretation of the ‘exceeds authorized access’ clause would attach criminal penalties to a breathtaking amount of commonplace computer activity,” she wrote. “If the ‘exceeds authorized access’ clause criminalizes every violation of a computer-use policy, then millions of otherwise law-abiding citizens are criminals.” The law could cover an employee who sends a personal email on a work computer, for example, or “criminalize everything from embellishing an online dating profile to using a pseudonym on Facebook.”

Legal experts and civil liberties advocates broadly praised the overall ruling. “This is an important victory for civil liberties and civil rights enforcement in the digital age,” said Esha Bhandari, the American Civil Liberties Union’s Speech, Privacy, and Technology Project deputy director. Electronic Frontier Foundation staff members Aaron Mackey and Kurt Opsahl also called the decision a victory, saying the court “provided good language that should help protect researchers, investigative journalists, and others.” (Both organizations previously filed briefs supporting Van Buren.)

CFAA can be used to crack down on legitimately malicious hacking, but it’s also notoriously vague, and different charges can carry penalties of up to 5, 10, or 20 years in prison. Critics argue that this combination threatens researchers and other people who use freely accessible information in unapproved ways. Federal prosecutors can stack up intimidating charges against targets, as was the case with activist Aaron Swartz, who died by suicide in 2013 while facing prosecution. Companies can also use it to harass journalists or employees that leak documents.

In theory, prosecutors now have to establish that users actually accessed parts of a system they were barred from entering. “I think it’s a really substantial deal,” Cornell University Law School professor James Grimmelmann tells The Verge. “It really clarifies that employees using computers disloyally is not a CFAA issue, and that blows away an enormous piece of criminal and civil use of the CFAA.” The ruling could also affect cases involving scraping, or mass-collecting publicly available data from websites.

Employees may still be guilty of other offenses, like stealing trade secrets, says Grimmelmann, and data scrapers could face CFAA charges if their activities cause a site to become inaccessible. But Van Buren raises the bar for what’s considered criminal hacking. “You get rid of a huge swathe of things that are not really high-tech, dangerous hacker crimes,” he says.

The ruling also leaves crucial questions unanswered, though. The court’s decision didn’t ultimately rest on the law’s overall impact or validity. It focused on a dictionary definition of one word (“so”) to decide if “exceeding authorized access” should be defined like a similar ban on computer use “without authorization” — which uses the gate metaphor. And while it says violators must have bypassed some metaphorical “gate,” it doesn’t firmly define these gates. On Twitter, Berkeley Law professor and CFAA expert Orin Kerr pointed to a footnote that implies gates could be technical barriers or rules in a contract — in Kerr’s words, something as potentially broad as “do not access this computer for a bad purpose.”

“It is still an open question whether the restriction on access has to be technological or contractual,” says former EFF staff member and computer crime attorney Hanni Fakhoury. As Fakhoury notes, the ruling does say it’s not necessarily “plausible” for the CFAA to hinge on fine semantic distinctions in private contracts. “It certainly seems to me they’re uneasy about the idea that the CFAA would somehow become a tool to criminalize contractual obligations,” he concludes. But it leaves this big question for lower courts to debate — at least until another case reaches the Supreme Court.

https://www.theverge.com/2021/6/5/22491859/supreme-court-van-buren-cfaa-hacking-law-scope-narrowed