NixOS must monitor remote access methods.

Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best.

Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

Automated monitoring of remote access sessions allows organizations to detect cyberattacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

Confirm the NixOS monitors remote access methods with the following command:

$ grep "LogLevel" /etc/ssh/sshd_config LogLevel VERBOSE

If "LogLevel" does not equal "VERBOSE", is missing, or is commented out, this is a finding.

Configure NixOS to monitor remote access methods by adding the following configuration to the /etc/nixos/configuration.nix or /etc/nixos/flake.nix:

services.openssh.logLevel = "VERBOSE";

Rebuild and switch to the new NixOS configuration: $ sudo nixos-rebuild switch