A Russian individual accused by US authorities of having ties to Russia’s FSB intelligence service entered a plea of not guilty on Thursday. The charge involves his alleged role in a cyber espionage operation executed by a tech firm targeting Western entities.
Denis Obrezko, who was extradited from Thailand after his capture there in November, entered his not guilty plea during a brief online hearing with a federal magistrate in Boston. This follows his indictment earlier in the week for allegedly conspiring to engage in computer fraud and abuse.
The 36-year-old faces charges stemming from what the indictment describes as a cyber espionage effort linked to the Russian government. The campaign is said to have taken aim at companies in the US and Europe, NATO-aligned European government bodies, and groups backing Ukraine amid Russia’s invasion.
According to the indictment, cybersecurity experts have been monitoring the hacking activities, identified as “Void Blizzard” and “Laundry Bear.” These names were also used by Microsoft and Dutch intelligence agencies in May 2025 when detailing a newly detected Russian cyber group.
If convicted, Obrezko could face a maximum prison sentence of 10 years.
His lawyer, Max Nemtsev, in an email said he plans “to vigorously contest the charges on both factual and legal grounds.”
According to the indictment, Obrezko had worked at Russia’s Federal Security Service, the domestic intelligence and security agency known as the FSB, from 2012 to 2017 before joining technology firm Yutek-NN, where he was a deputy director.
The indictment said that the company conducted cyber espionage campaigns at the behest of the Russian government.
Yutek could not be reached for comment.
The indictment said Obrezko and other employees and associates of Yutek conspired since at least 2023 to extract email and other data from companies’ systems using tools like fake domain names, VPNs and proxy servers.
Victims included a social media network; a US development company; a cloud software company; and a US-based educational institution.
Court filings say the FBI has identified at least 11 US companies that have been hacked, a number it believes to be just a fraction of Void Blizzard’s victims.
According to the indictment, Obrezko’s phone also stored a file containing AI-generated summaries of more than 13,000 stolen emails from members of an Eastern European parliament.
After Microsoft in May 2025 published a report detailing the activities of Void Blizzard, Obrezko corresponded with an unnamed co-conspirator who went by the alias “Ethan Hunt,” the same name as the character Tom Cruise plays in the “Mission: Impossible” movie franchise, the indictment said.