Bottom line: macOS users should take immediate action to protect themselves from this new threat.
What's happening: Cybersecurity researchers at Kaspersky discovered AmnesiaStealer, a novel macOS infostealer, in March 2022. The attackers gained remote control over the victim’s browser to steal cookie data, including login credentials and session tokens.
What to do: Security teams should immediately implement security updates and configure their systems to block suspicious traffic, and individuals should keep their macOS systems and browsers up to date with the latest security patches.