Solaris and PAM configs

I need to configure Duo to work with Solaris 10 and Solaris 11 which I’ve done to a point. The problem we are seeing once we log into the server and then su to root it doesn’t ask for the password. Basically, it will let anyone into root. This works as in should in Redhat. What PAM configs should I look at (in Solaris) to get the server to prompt me for root’s password?