Wikipedia defines the attack surface of an application, network, or computer system as scope of functionality available to any application user. The goal is to minimize entry points for unauthenticated, anonymous users. Windows Server Server Core installation option in Windows Server 2008 is the real head-turner. Microsoft has created a choice for sysadmins to deploy a minimal system that does not include the typical Windows Explorer and GUI. It’s a win-win for security pros who have less to lock down and disable, making deployment faster and auditing easier.”]
Source: https://www.darkreading.com/analytics/tech-insight-to-go-deep-on-security-get-past-the-surface