Kaseya supply chain attack: What you need to know

Kaseya experienced a large-scale supply-chain ransomware attack on July 2, 2021 in which the REvil group exploited a zero-day (CVE-2021-30116) in Kaseya VSA to distribute a malicious update that dropped a REvil encryptor and side-loaded a malicious mpsvc.dll into a legitimate Microsoft Defender binary, impacting MSPs and hundreds of U.S. businesses; the report includes technical details, IOCs (file paths, hashes, and an onion C2), and immediate mitigation and detection steps.