Rhysida is a ransomware group that encrypts data on victims' computer systems and threatens to make it publicly available unless a ransom is paid.^[1] The group uses eponymous ransomware-as-a-service techniques, targets large organisations rather than making random attacks on individuals, and demands large sums of money to restore data.^[2] The group perpetrated the notable 2023 British Library cyberattack^[1] and Insomniac Games data dump.^[3] It has targeted many organisations, including some in the US healthcare sector, and the Chilean army.^[4]

In November 2023, the US agencies Cybersecurity and Infrastructure Security Agency (CISA), FBI and MS-ISAC published an alert about the Rhysida ransomware and the actors behind it,^[5] with information about the techniques the ransomware uses to infiltrate targets and its mode of operation.^[6]

The group takes its name from the genus of centipedes, and uses a centipede logo.^[4]

• British Library cyberattack, 2023
• Insomniac Games data dump, releasing details of the Marvel's Wolverine game and employee details.^[3][7]
• Chilean army^[4][8]

The US CISA report states:^[6]

Threat actors leveraging Rhysida ransomware are known to impact “targets of opportunity,” including victims in the education, healthcare, manufacturing, information technology, and government sectors. Open source reporting details similarities between Vice Society (DEV-0832) activity and the actors observed deploying Rhysida ransomware. Additionally, open source reporting has confirmed observed instances of Rhysida actors operating in a ransomware-as-a-service (RaaS) capacity, where ransomware tools and infrastructure are leased out in a profit-sharing model. Any ransoms paid are then split between the group and the affiliates.