use strict;
use LWP;
use LWP::UserAgent;
use LWP::Debug qw(+);
my $URI = 'https://site.com/cc/login.do';
my $user = 'user';
my $pass = 'pwd';

# define user agent
my $ua = LWP::UserAgent->new();
$ua->agent("USER/AGENT/IDENTIFICATION");

#set proxy
$ua->proxy(['http','https'], 'http://nt_user:nt_pwd@proxy.domain.com:8080');

# make request
my $request = HTTP::Request->new(GET => $URI);

# authenticate
$request->authorization_basic($user, $pass);

# except response
my $response = $ua->request($request);

# get content of response
my $content = $response->content();

# do whatever you need to do with the content here
print $content;