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 has issued a public warning urging users of webmail platforms, including Gmail, to enable two-factor authentication (2FA) to mitigate a growing ransomware threat.

The FBI and the U.S. Cybersecurity and Infrastructure Security Agency are urging users of popular email services like Gmail and Outlook to be on the lookout for a dangerous and potentially costly ransomware scheme. A bulletin released this week detailed a warning for the Medusa ransomware gang, a group that’s been active since 2021.