Magnolia 5.3 reached end of life on June 30, 2017. This branch is no longer supported, see End-of-life policy.
The Security App module installs the Security app in which access to Magnolia is managed. See Security for more information.
The Security App module is bundled with Magnolia and typically already installed. You can download it from our Nexus repository
Security App is a Community Edition module. It is typically already installed. Launch the Configuration app and go to /modules/security-app
to check.