The Dork: inurl:ctl/Login/Default.aspx reveals the CMS Login page for the Dot Net Nuke CMS.
Versions DNN 7.1.0 and earlier / DNN 6.2.8 and earlier are vulnerable to XXS ( CVE-2013-4649 ).
This can be tested by reviewing the page source code and searching for default.css where the version will precede it.