Fancy Bear is thought to be responsible for the hacks on the Democratic National Committee (DNC) during the US elections last year. US intelligence believe the group hacked the DNC and leaked emails to WikiLeaks to help Donald Trump win the election.
As The Daily Beast reported in July, Microsoft sued the hackers in a federal court last year, accusing them of hacking, cybersquatting, and infringing on Microsoft's trademarks.
The suit was not aimed at bringing the individuals behind Fancy Bear to court, but rather at seizing the domain names they used to control their malware on infected computers.
The domains the hackers registered included ones that look similar to Microsoft's real domains, such as livemicrosoft[.]net or rsshotmail[.]com.
US district judge Gerald Bruce Lee authorized Microsoft to take over dozens of these domains so that infected computers connect to Microsoft's servers instead of the attackers' machines.
Microsoft had also filed a motion for a permanent injunction against the Fancy Bear hackers, which the court ruled on yesterday in favor of Microsoft.
Judge Lee ruled that the hackers are "permanently restrained and enjoined" from sending malware to Microsoft's customers and from hacking computers to spy on users.
Microsoft had sued the hackers as John Doe and served papers to email addresses used to register the domains. Since the hackers never turned up to court proceedings, Microsoft was awarded victory by default.
The proposed default ruling on Microsoft's motion for a permanent injunction notes that Fancy Bear hackers are enjoined from using Microsoft's trademarks and internet addresses in a way that could result in deception of Microsoft's customers.
The injunction covers trademarks and brands like ActiveX, AppLocker, Azure, and Bing, as well as "confusingly similar variants".
Microsoft's suit against Fancy Bear hackers uses tactics seen in lawsuits it used to take down massive botnets, including Rustock and Kelihos.