A security researcher has discovered a new malware targeting macOS systems. The stealth malware, dubbed OSX/MaMi, was discovered by security researcher Patrick Wardle. The malware can be used to steal sensitive user information and is undetectable by current anti-virus programs.

Wardle believes that MaMi is closely related to the DNSUnlocker malware that targeted Windows systems in 2015.

“OSX/MaMi isn't particular advanced - but does alter infected systems in rather nasty and persistent ways. By installing a new root certificate and hijacking the DNS servers, the attackers can perform a variety of nefarious actions such as man-in-the-middle'ing traffic (perhaps to steal credentials, or inject ads),” wrote Wardle.

He has suggested some steps to ensure that your system is not infected - either reset the DNS server and delete the malicious certificate or simply reinstall macOS; I would go with the latter option.

You can also download and install a free and open source Firewall, called Lulu, that Wardle has published on GitHub.