Medusa ransomware is dangerous enough that the FBI sent a 15-page memo warning people and entire industries. The agency says hundreds of victims have been reported and entire fields, from medicine to education and technology to manufacturing have been hit.

According to a cybersecurity advisory, Medusa relies on a “double extortion model” that encrypts a victim’s data then threatens to release it publicly. In the past week, law enforcement agencies including the Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) have issued a warning about the ongoing threat of Medusa ransomware.

Federal authorities are warning users of Gmail, Outlook, and other popular email services about dangerous ransomware linked to a group of developers who have breached hundreds of victims' data, including people in the medical,