VirtualBox 4.3 Guest Additions on OSX guest [closed]

You're right, VirtualBox doesn't have guest additions for OSX. https://www.virtualbox.org/wiki/Guest_OSes

They only list Mac OSX Server (Leopard, Snow Leopard) under Mac and even that doesn't have guest additions.

It has something to do with licensing restrictions:
https://forums.virtualbox.org/viewtopic.php?f=22&t=31104