Artem Stryzhak gets 70 months in prison for Hive and Nefilim ransomware attacks, while the FBI offers $11 million for his alleged co-conspirator.A federal court in Brooklyn has sentenced Artem Stryzhak, a Ukrainian national, to 70 months in prison for using ransomware to extort millions of dollars from victims. The U.S. Attorney’s Office for the Eastern District of New York announced it in a press release, and it also says an $11 million reward remains for a co-conspirator who’s still at large.“Earlier today, in federal court in Brooklyn, Artem Stryzhak, a Ukrainian national, was sentenced by United States District Judge Pamela K. Chen to 70 months in prison for using ransomware to extort millions of dollars from victims.” reads the DoJ’s press release. “The defendant pled guilty in December 2025 to conspiracy to commit fraud, extortion, and related activity in connection with computers. “In December, Artem Aleksandrovych Stryzhak pleaded guilty in the U.S. for Nefilim ransomware attacks. The Ukrainian citizen was arrested in Spain in 2024 and extradited to the US in April 2025. He pleaded guilty to conspiracy to commit computer fraud, extortion, and related activityNefilim ransomware was used to encrypt networks worldwide, including in the Eastern District of New York, causing millions in losses from ransom payments and system damage. Attackers employed a customized ransomware executable in each attack, generating unique decryption keys and tailored ransom notes for victims. In June 2021, Nefilim administrators granted Artem Stryzhak access to the ransomware code in exchange for 20% of his ransom proceeds, which he deployed via his account on the administrators’ online platform.Stryzhak and co-conspirators researched victims using online databases to collect information on their net worth, size, and contacts. After gaining network access, they stole data to pressure companies into ransom payments. Nefilim notes warned that stolen data would be posted on publicly accessible “Corporate Leaks” sites maintained by the administrators if victims did not comply.Volodymyr Tymoshchuk, Stryzhak’s co-defendant and Nefilim admin, is a serial ransomware cybercriminal who is still at large. According to court documents, his first role was with Nefilim. Starting around June 2021, he joined the ongoing Nefilim conspiracy as an affiliate and got access to the ransomware. In exchange, he agreed with one of the group’s administrators, Volodymyr Tymoshchuk, to pay the administrators 20 percent of the ransom proceeds. Even crime has licensing fees.One of those attacks came in June 2021, when Stryzhak stole data from a company in the oil and gas transportation industry. About a week later, he created email addresses that went into a ransom note sent to the victim. He kept deploying Nefilim ransomware through at least October 2021.Separately, he also joined the Hive ransomware group as one of its earliest affiliates. From June 2021 to January 2023, Hive’s conspirators attacked about 1,500 victims worldwide, including government entities, hospitals and businesses. The attacks caused major disruption to daily operations around the world and affected responses to the COVID-19 pandemic. One hospital had to give up digital technology to treat its patients and couldn’t take in new ones right after the attack.As a Hive affiliate, Stryzhak and his co-conspirators hit seven victims, including law firms, a dentist’s office and a healthcare provider, during the pandemic. Those victims couldn’t get to their encrypted data. The FBI, as part of a months-long effort to disrupt Hive, gave a decryption key to one of Stryzhak’s victims, so that victim recovered its data without paying a ransom.U.S. Attorney Joseph Nocella, Jr. thanked the FBI’s New York Field Office, the Justice Department’s Office of International Affairs and its Computer Crime and Intellectual Property Section, and Spanish law enforcement for helping to capture him. “Ransomware attacks like those committed by the defendant wreak enormous havoc—harming victim companies that pay millions in remediation and ransoms, preventing hospitals and other critical facilities from accessing data, and putting sensitive information in the hands of bad actors,” stated United States Attorney Nocella. “Today’s sentence reflects that cybercriminals cannot hide from law enforcement and will face significant punishment for their criminal conduct. We remain determined to capture Volodymyr Tymoshchuk, a serial ransomware developer and Stryzhak’s co-conspirator.”The State Department’s Transnational Organized Crime Rewards Program is offering up to $11 million for information that leads to the arrest, conviction or location of Tymoshchuk. Anyone with information can call the FBI at +1-917-242-1407 or email TymoTips@fbi.gov, contact a local field office if in the United States, or reach the nearest U.S. Embassy if overseas. Follow me on Twitter: @securityaffairs and Facebook and MastodonPierluigi Paganini(SecurityAffairs – hacking, newsletter)