Google has sued hackers believed to be part of a cybercrime gang that has stolen user information from around the world.
A complaint names two Russians and 15 unknown individuals said to be behind Glupteba, a malicious "botnet" that has infected over a million computers.
Criminals use these systems of compromised devices to hack private data.
It is the first case Google has launched against a botnet.
According to a lawsuit filed in New York and unsealed on Tuesday, the botnet built by Dmitry Starovikov, Alexander Filippov and their associates has become a "modern technological and borderless incarnation of organised crime".
Glupteba's malicious software - which was first detected in 2011 - is spread by third-party download sites, online movie streaming services and a website which fraudulently purported to be affiliated with YouTube, which is owned by Google.
Private information stolen through the botnet can be used to commit crimes like fraud.
Court documents allege that the Glupteba botnet stands out from others because of its "technical sophistication".
Mr Starovikov and Mr Filippov - the only two hackers whose names were known - could not be immediately located for comment on the charges.
In a blog post, Google disclosed that a company investigation had found Glupteba currently involved approximately a million compromised Windows devices.
At times, the botnet is believed to grow at a rate of thousands of new devices per day.
"Glupteba is notorious for stealing users' credentials and data, mining cryptocurrencies on infected hosts, and setting up proxies to funnel other people's internet traffic through infected machines and routers," the blog post said.
Google believes it has disrupted the hackers' "key command and control infrastructure", preventing those behind Glupteba from having control of the botnet "for now".
The lawsuit accuses Mr Starovikov, Mr Filippov and the 15 unnamed defendants of computer fraud and abuse, trademark infringement and several other charges.
The legal action is being brought under the Racketeer Influenced and Corrupt Organizations (Rico) Act, which is often used to prosecute members of organised crime groups such as the Mafia, outlaw biker gangs or drug trafficking networks.
A report from the Center for Strategic and International Studies and computer security firm McAfee found that cybercrime led to nearly $1 trillion in losses in 2020.