Artem Stryzhak, a resident of Barcelona, received a 70-month prison term after admitting guilt to conspiracy charges stemming from a series of cyberattacks targeting hospitals, government agencies and commercial entities across multiple continents.
The 36-year-old Ukrainian national worked as an affiliate with the Nefilim ransomware operation throughout 2021, conducting attacks against targets in the United States, Canada and Australia. He paid Nefilim's administrators, including co-conspirator Volodymyr Tymoshchuk, a 20% share of all ransom payments extracted from compromised organizations. Stryzhak later transitioned to the Hive ransomware gang, remaining active with that group from October 2021 until January 2023.
During his involvement with Hive, Stryzhak participated in attacks on healthcare systems, public institutions and private companies throughout the COVID-19 pandemic. The ransomware operation encrypted thousands of organizations across 80 nations and generated millions of dollars through extortion. One documented case involved a hospital that could not admit new patients as a result of a Hive attack during the pandemic.
According to Assistant FBI Director Brett Leatherman, "Artem Stryzhak is a prolific cybercriminal who worked with multiple ransomware groups to target U.S. businesses and hospitals. These groups disrupted patient care and caused more than $100 million in losses."
Spanish authorities arrested Stryzhak in June 2024, and he was extradited to the United States in April 2025. In December 2025, he entered guilty pleas to two counts of conspiracy to commit fraud, extortion and related computer crimes.
Assistant Attorney General A. Tysen Duva stated that "This sentence concludes a years-long, multi-continent investigation into a defendant who participated in cyberattacks against Americans' businesses and health care."
Tymoshchuk, who served as an administrator for Nefilim and is also implicated in the LockerGoga and MegaCortex ransomware operations, remains at large. U.S. authorities have offered an $11 million reward for information leading to his capture. The Department of Justice has also posted a $15 million bounty for intelligence on other Hive members.
U.S. Attorney Joseph Nocella Jr. emphasized that prosecutors "remain determined to capture Volodymyr Tymoshchuk." The FBI previously dismantled the Hive operation following an extended investigative effort.
