There are several different options you can use to increase the security of your single sign on authentication systems. You could replace this type of system with a two factor authentication system. 2FA systems add a layer of security in front of your existing authentication processes. By adding this additional layer, you can eliminate potential problems and issues with unauthorized access to your network and resources.
You Can Use SSL Certificates as Another Option to Improve Security with Single Sign On Systems
Another option you can use with your single sign on authentication systems are SSL certificates. These types of certificates establish a secure connection to your network and resources before the user enters their log-in information. If there is not a secure connection detected, the system will not authenticate the user, or may limit their access to generally shared resources.