Federal agencies are warning Gmail and Outlook email users of a costly ransomware scheme that has already affected more than 300 victims. The FBI and the U.S. Cybersecurity and Infrastructure Security Agency issued the advisory, detailing a warning about the Medusa hacking organization, which has been active since 2021.

The FBI, MS-ISAC and CISA released a joint cybersecurity advisory about the Medusa ransomware variant, advising people and organizations to use multifactor authentication and other strategies to prevent attacks from the ransomware-as-a-service provider that has targeted hundreds since 2021.

The FBI and the U.S. Cybersecurity and Infrastructure Security Agency are warning email users against a dangerous ransomware scheme.