4.5
IG1 IG2 IG3

Implement and Manage a Firewall on End>User Devices

Asset Type: Devices
Security Function: Protect

Description

Implement and manage a host-based firewall or port-filtering tool on end-user devices, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed.

Implementation Checklist

1
Assess current protection controls in place
2
Configure and deploy required security controls
3
Test control effectiveness in non-production environment
4
Deploy to production and verify functionality
5
Document configuration and operational procedures
6
Review and document current firewall rule sets
7
Define required firewall rules based on business needs
8
Implement and test firewall rules
9
Schedule periodic rule review and cleanup

Threats & Vulnerabilities (CIS RAM)

Threat Scenarios

Direct Endpoint Exploitation from Network

Confidentiality

Attackers exploit services running on end-user devices (RDP, SMB, WinRM) that are accessible because no host-based firewall blocks inbound connections from unauthorized sources.

Peer-to-Peer Malware Spread Between Workstations

Availability

Malware on one workstation spreads directly to other workstations via network shares and services because no endpoint firewall restricts workstation-to-workstation traffic.

Vulnerabilities (When Safeguard Absent)

No Default-Deny Firewall on End-User Devices

Without a host-based firewall with a default-deny inbound rule, end-user devices accept connections on all ports, exposing every running service to the network.

Unrestricted Outbound Communication from Endpoints

Without firewall port filtering on endpoints, malware can establish outbound connections to command-and-control servers on any port or protocol.

Evidence Requirements

Type Evidence Item Collection Frequency
Technical Configuration screenshots or exports showing protection controls enabled Captured quarterly
Document Procedure documentation for protection measures Reviewed annually
Technical Firewall rule set export and review documentation Reviewed quarterly
Record Firewall change request and approval records Per change
Document Governing policy document (current, approved, communicated) Reviewed annually