SAML (Security Assertion Markup Language) is an XML-based standard used for exchanging authentication and authorization data, primarily in web-based single sign-on (SSO) scenarios, and is implemented in the Elastic Stack to enhance security for clusters and users. It involves three main actors: the SAML Identity Provider, which authenticates users; the SAML Service Provider, which requests and consumes authentication data; and the user agent, typically a browser. The Elastic Stack functions as a SAML 2.0 compliant Service Provider, with Kibana and Elasticsearch playing pivotal roles in handling SAML messages and authentication flows. Configuring SAML in the Elastic Stack involves setting up a few lines in the elasticsearch.yml file and adjusting settings in Kibana, which streamlines the authentication process and enhances user experience by reducing password fatigue. This implementation is aligned with best practices, leveraging XML Digital Signatures and encryption to ensure message integrity and authenticity, while also offering benefits such as compliance support and improved security through centralizing user credential management.