The FBI first became aware of RagnarLocker in April 2020 and subsequently produced a FLASH to disseminate known indicators of compromise (IOCs) at that time. This FLASH provides updated and additional IOCs to supplement that report. As of January 2022, the FBI has identified at least 52 entities across 10 critical infrastructure sectors affected by RagnarLocker ransomware, including entities in the critical manufacturing, energy, financial services, government, and information technology sectors. RagnarLocker ransomware actors work as part of a ransomware family1, frequently changing obfuscation techniques to avoid detection and prevention.