Sixgill researchers have encountered a post in one of the leading, closed Russian cybercrime message boards. The author of the thread announced a RAT dubbed Proton, intended for installation exclusively on MAC OS devices. The author offered this product in one of the leading underground cybercrime markets. This report contains information about the malware.

https://www.cybersixgill.com/wp-content/uploads/2017/02/02072017%20-%20Proton%20-%20A%20New%20MAC%20OS%20RAT%20-%20Sixgill%20Threat%20Report.pdf