NixOS must enable the built-in firewall.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-268078SRG-OS-000298-GPOS-00116ANIX-00-000010SV-268078r1039122_rule2024-10-251
Description
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
ℹ️ Check
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
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