Securing GlassFish requires a multi-layered approach involving the immediate change of default passwords, enabling secure admin via SSL, and running the server as a non-root user to harden the environment. Further measures include updating the master password, configuring firewall restrictions, and enabling audit logging for enhanced security. For comprehensive, step-by-step instructions, consult the Eclipse GlassFish Security Guide . Securing your GlassFish. Hardening Guide.