A Russian man accused by U.S. prosecutors of involvement in a Russian government-linked cyber espionage campaign entered a plea of not guilty during a brief virtual hearing in Boston on Thursday.
The defendant, identified in court documents as Denis Obrezko, was extradited from Thailand last month after being arrested there in November. He appeared virtually before a federal magistrate judge following an indictment filed earlier this week that charges him with conspiring to commit computer fraud and abuse.
The indictment, according to court filings, alleges that Obrezko, 36, took part in a cyber espionage operation that targeted a range of Western targets, including U.S. and European companies, European government agencies aligned with NATO, and organizations supporting Ukraine in response to Russia's invasion. Prosecutors say the hacking activity has been tracked by cybersecurity researchers under the names "Void Blizzard" and "Laundry Bear," the same labels cited in May 2025 by Microsoft and Dutch intelligence agencies when they described a newly identified Russian cyber group.
Prosecutors say Obrezko faces a maximum prison sentence of 10 years if convicted. His attorney, Max Nemtsev, declined comment in court but told reporters in an email that he intends to "vigorously contest the charges on both factual and legal grounds."
Court documents outline parts of Obrezko's background. The indictment states that he was employed by Russia's Federal Security Service, the domestic intelligence and security agency commonly known by its initials FSB, from 2012 to 2017. After that period he allegedly took a position as deputy director at a technology company named Yutek-NN.
The indictment asserts that Yutek-NN carried out cyber espionage campaigns on behalf of the Russian government. The firm could not be reached for comment, according to the filings.
Details in the indictment describe a conspiracy dating back at least to 2023 in which Obrezko and other Yutek employees and associates allegedly extracted email and other data from victims' systems. The methods cited include the use of counterfeit domain names, virtual private networks and proxy servers to gain access and conceal activity.
Specific victims listed in court papers include a social media network, a U.S. development company, a cloud software company and a U.S.-based educational institution. The FBI, the filings say, has identified at least 11 U.S. companies that were hacked, a figure the bureau believes represents only a portion of Void Blizzard's victims.
Additional material cited by prosecutors includes a file found on Obrezko's phone that allegedly contained artificial intelligence-generated summaries of more than 13,000 stolen emails taken from members of an Eastern European parliament. The indictment also notes that after a May 2025 report from Microsoft detailed Void Blizzard's activities, Obrezko communicated with an unnamed co-conspirator who used the alias "Ethan Hunt," according to the charging documents.
The case will proceed through the federal court system in Boston, where further pretrial proceedings and any trial would determine the legal outcome of the allegations laid out in the indictment.