Cgi.auth_user ok but cgi.remote_user is blank

First time installing Lucee. I’ve installed version on Windows Server 2012 and I am using IIS 8.5 with basic authentication (and https). I ran into problems testing code and by dumping the CGI variables I discovered that cgi.remote_user is blank, but cgi.auth_user is not. Rather than change thousands of lines of code to use cgi.auth_user, I was trying to figure out what is causing this discrepancy. Alternatively, is there a ‘master’ template that is called on every Lucee request that could be used to modify the CGI variables?