While we recognize that identity is the most important security boundary in today’s landscape, we also believe that properly configured firewalls still have a vital role to play in the defense-in-depth approach to information security.
Many guidelines on domain controller (DC), server, and workstation hardening recommend configuring host-based firewalls to reduce the attack surface, making it harder to perform remote code execution, lateral movement, and authentication relay attacks. However, there is no single comprehensive source of information on this topic, leading to overly permissive host-based firewalls in most organizations. Few admins have the knowledge and courage to change this status quo.
In this session, we will try to address this situation by discussing a set of highly restrictive DC firewall rules and Remote Procedure Call (RPC) filters that can be applied to most production environments. We will touch member servers and workstations as well and we will also discuss how to make the process of firewall configuration flexible and repeatable using PowerShell. After this talk, we hope to see fewer Any-to-Any firewall rules during future Active Directory security assessments.