HTTP Auth using current WHM account credentials

[benklopfer]

I am using WHM as a reseller to manage other user's accounts. On my reseller site, I want to have a members area where users must authenticate before viewing the content. Easy enough, but the kicker is I want it to be linked up with their CPanel/WHM username and passwords. Does anyone know where to find the CPanel/WHM password file or how to accomplish this? I've searched around but I can't figure it out. Thanks in advance.

[eth00]

cPanel and WHM users are just normal system users with stored in /etc/shadow