The REvil gang, a major Russian-speaking ransomware syndicate, appears to be behind the attack The attack came despite President Joe Biden's threat of 'retaliation' to Russian President Vladimir Putin if they continued The massive scale of the attack paralyzed the networks of at least 200 U.S. companies on Friday John Hammond of the security firm Huntress Labs said the criminals targeted a software supplier called Kaseya Kaseya earlier in the day had said in a press release that the 'potential attack' had been ' limited to a small number of on-premise customers only'