A group of hackers installed cryptocurrency mining malware on 9000 computers over two years, antivirus company Kaspersky Lab claims.
The hackers controlled one batch of 4000, and another of 5000 computers.
"According to analysts, the hacker mining network brings its owners up to $30,000 per month," the publication quotes a Kaspersky source as saying.
Total earnings are estimated to be $209,000 so far for Monero alone, while the total income is harder to determine.
Cryptocurrency hacking is currently a topic of interest in Russia’s ongoing battle with regulation.
In July, the country’s Internet advisor to Vladimir Putin suggested up to an astonishing 30 percent of domestic devices were infected with a mining virus, comments which even fellow minister Dmitry Marinichev soon denied were true.
“In regions with lower bandwidth instances are reduced, but we’re looking at 20 to 30 percent of devices being infected - iPhones and Macs are less prone,” Klimenko had said.
Kaspersky has meanwhile warned about more legitimate threats affecting consumers, including August’s Trojan banker malware known as ‘Jimmy.’