Uses the new Onelogin PHP-SAML Toolkit. Review its dependences
In order to install it, move the onelogin-saml-sso inside the wp-content/plugins folder. Once moved, activate the plugin and configure it.
This kind of WP hosting used to cache plugins and protect the wp-login.php view. You will need to contact them in order to disable the cache for this SAML plugin and also allow external HTTP POST to wp-login.php
Version 2.4.3 includes a security patch that contains extra validations that will prevent some kind of elaborated signature wrapping attacks and other security improvements. Previous versions are vulnerable so we highly recommended to upgrade to >= 2.4.3.
Read: https://wpvulndb.com/vulnerabilities/8508
To mitigate that, place the script at the root of WordPress and execute it (later remove it) https://gist.github.com/pitbulk/a8223c90a3534e9a7d5e0a93009a094f