SAN FRANCISCO—Anti-malware software-maker Malwarebytes has scored a legal victory under a rarely litigated provision of Section 230, winning dismissal of a suit alleging it used its software to try and edge out a competitor.

U.S. District Judge Edward Davila of the Northern District of California on Tuesday ruled Malwarebytes cannot be held liable for its decision to filter Florida-based Enigma Software Group USA's anti-malware products as “potentially unwanted programs,” despite allegations it did so for anti-competitive reasons.

Davila granted a motion to dismiss under Section 230(c)(2)(B), which gives immunity to companies or individuals that provide the “technical means to restrict access” to certain kinds of content. That particular subsection comes up less frequently in litigation, especially when compared to Section 230's provisions relating to intermediary liability.

The judge took a broad interpretation of the provision, ruling providers of filtering technology do not have to show their decisions are based on “good faith.” He also ruled the law allows them to target a wide range of content that would fall under the definition of “objectionable.”

Enigma had argued that the term “objectionable” should be read more narrowly, taking into account preceding words in the statute. The law grants certain immunities for filtering material that is “obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable.”

Citing Zango Inc. v. Kaspersky Lab Inc.—a 2009 decision by the U.S. Court of Appeals for the Ninth Circuit involving the Russia-based cybersecurity firm Kaspersky Lab—Davila wrote: “Enigma overlooks Zango's clear holding that § 230(c)(2)(B) immunity applies to 'a provider of computer services that makes available software that filters or screens material that the user or the provider deems objectionable.'”

“The Ninth Circuit held that malware, as Kaspersky defined it, was properly within the scope of 'objectionable' material. In that respect, the court agrees with Malwarebytes that Zango is factually indistinguishable from the scenario here,” the judge concluded. The Ninth Circuit panel affirmed a lower court's decision granting summary judgement in favor of Kaspersky.

“This is a critical win, not only for Malwarebytes, but for all security providers who will continue to have legal protection to do what is right for their users,” Marcin Kleczynski, chief executive officer of Malwarebytes, said of Judge Davila's decision in a statement. The company is represented by Fenwick & West partner Tyler Newby.

“We respect Judge Davila, and we understand he has taken a very expansive view of the statute,” said Terry Budd of the Budd Law Group, based near Pittsburgh, who represents Enigma. “We look forward to our appeal and having the Ninth Circuit do a full review of our case and our claims.”

Enigma is also represented by K&L Gates.

The case has a complex history. According to Enigma's 2016 complaint—originally filed in the Southern District of New York—Malwarebytes' software quarantines and disables Enigma's anti-malware programs if they are installed on the same computer. Enigma alleges that Malwarebytes did this through an update to its “possibly unwanted programs” definitions as a retaliatory step after Enigma filed an earlier libel lawsuit against a website that had a commercial relationship with Malwarebytes, BleepingComputer.com.

That lawsuit centered on critical remarks posted by a BleepingComputer.com forum moderator about Enigma's software. After a judge denied a motion to dismiss the case under Section 230, the litigation settled in February this year.

Malwarebytes rejected assertions that it targeted Enigma's “SpyHunter” and “RegHunter” programs for retaliatory or anti-competitive reasons, saying in its motion to dismiss that it began flagging them in October 2016 because the programs are deceptive. “Enigma's programs aggressively—and deceptively—identified standard web browser cookies as 'infections' and 'spyware' to scare users into purchasing Enigma software,” it said.