This joint Cybersecurity Advisory was developed by the Federal Bureau of Investigation (FBI) and the U.S. Secret Service (USSS) to provide information on BlackByte ransomware. As of November 2021, BlackByte ransomware had compromised multiple US and foreign businesses, including entities in at least three US critical infrastructure sectors (government facilities, financial, and food & agriculture). BlackByte is a Ransomware as a Service (RaaS) group that encrypts files on compromised Windows host systems, including physical and virtual servers.