I've done a SSO module based on CAS and now it is available.
It's very easy to deploy.
here is the project address on GitHub
if you have cacti on /var/www/html/cacti/, you can install like this:
install php-ldap and set Cacti to validate from ldap server.
then do like this:
git clone https://github.com/tonychee7000/cacti_cas_sso
cp -r cacti_cas_sso/* /var/www/html
tar xvf current.tgz
cp -r CAS /var/www/html
then you need to modify index.php
to match your ldap and CAS server configuration.
last and important, run ldap_import.py and set permissions to the user in Cacti.
if all above is done, you can visit http://your_cacti_site/ to test it.
this module have no any limitation on copyright, you can use it for any perporse.