Our canonical malware question is a gem. At the time it was written, though, the various malware that encrypts your files weren't even a thing. We periodically get questions on how to recover from those, and people are usually just uselessly directed to our canonical thread.
It used to be that the only advice was restore from backup if you have a backup, or pay up if you don't. I've recently seen mention of some tools for specific malware packages (but don't recall the details). Whatever the current recovery options are (even if there aren't any), it would be nice to add this class of malware to our thread.
I'm not familiar enough with this subject to write an answer. Does anybody want to tackle this?