OFAC sanctions Operation Zero and Sergey Zelenyuk for exploit-broker activity
Russian exploit-acquisition firm publicly sanctioned by the U.S. Treasury OFAC in February 2026, alongside its founder Sergey Zelenyuk, for operating a market in zero-day vulnerabilities and exploit…
Summary
U.S. Treasury OFAC sanctioned Russian national Sergey Zelenyuk and his firm Operation Zero — alongside named affiliates — for operating an exploit-acquisition market that received and resold eight proprietary U.S. Government cyber tools stolen by an American insider. The insider, Williams, pleaded guilty 29 October 2025 to two counts of theft of trade secrets and was sentenced 24 February 2026 to 87 months in federal prison. The action is the **first U.S. cyber-sanctions designation of a commercial zero-day broker**, extending the cyber-sanctions regime from operators (Evil Corp, LockBit, Salt Typhoon's MSS contractor) to the offensive-tooling supply chain that feeds them.