A suspected Russian hacker is in U.S. custody after being extradited from Thailand and has been charged with facilitating a campaign of cyberattacks carried out by a Russia-aligned group that victimized numerous U.S. companies.
Denis Obrezko, who was arrested in Thailand in November, made his initial appearance in federal court in Boston on Tuesday in connection with a case that U.S. authorities alleged concerned a large-scale cyber espionage campaign being carried out by a group known as Void Blizzard.
The 36-year-old was charged with conspiring to commit unauthorized access to a protected computer and is now being held without bond in a case that is being prosecuted by the U.S. Department of Justice’s National Security Division.
The Justice Department had no comment on Wednesday, and a court-appointed lawyer for Obrezko did not respond to a request for comment.
Thailand’s Ministry of Foreign Affairs said in a statement the Thai government’s decision to extradite Obrezko was in accordance with Thailand’s domestic law and its obligations under the related treaties on extradition, “while fully respecting the due process of law of the defendant.”
Void Blizzard had been flagged by Microsoft in a May 2025 report as what it said was a new group that it had observed conducting cyber espionage activity against organizations important to Russian government objectives.
