Title

NixOS must enable the built-in firewall. (Cat II impact)

Discussion

Without the ability to immediately disconnect or disable remote access, an attack or other compromise taking place would not be immediately stopped. Operating system remote access functionality must have the capability to immediately disconnect current users remotely accessing the information system and/or disable further remote access. The speed of disconnect or disablement varies based on the criticality of mission's functions and the need to eliminate immediate or future remote access to organizational information systems. The remote access functionality (e.g., RDP) may implement features such as automatic disconnect (or user-initiated disconnect) in case of adverse information based on an indicator of compromise or attack. Satisfies: SRG-OS-000298-GPOS-00116, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00232

Check Content

Verify NixOS has the network firewall enabled with the following command: $ grep firewall.enable /etc/nixos/configuration.nix networking.firewall.enable = true; If "networking.firewall.enable" is not set to "true", is commented out, or is missing, this is a finding.

Fix Text

Configure /etc/nixos/configuration.nix to enforce firewall rules by adding the following configuration settings: networking.firewall.enable = true; Rebuild the system with the following command: $ sudo nixos-rebuild switch

Additional Identifiers

Rule ID: SV-268078r1039122_rule

Vulnerability ID: V-268078

Group Title: SRG-OS-000298-GPOS-00116

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.