How to Infiltrate Router's Setting Page?

A friend of mine has set up MAC security on his router. I can use MAC spoof to access the internet but since I use Kali Linux in a Virtual environment so accessing internet is not a very good option in Vmware plus I've to game online which is a far fetched idea for a Virtual environment. And as you guys might know that MAC spoofers do NOT really work for windows (they either get stuck, have compatibility issues or just don't work) so I can't have it on windows either, so I'm trying to have access to the router's settings page so I could add my PC's MAC there. But he has changed the password of router's settings page (its not the default one). I have tried all possible combinations but haven't succeeded.

Could anyone of you help me with this?