Check: ANIX-00-001460
Anduril NixOS STIG:
ANIX-00-001460
(in version v1 r1)
Title
NixOS must notify designated personnel if baseline configurations are changed in an unauthorized manner. (Cat II impact)
Discussion
Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's IMO/ISSO and SAs must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000445-GPOS-00199, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201
Check Content
Verify NixOS notifies if baseline configurations are changed with Advanced Intrusion Detection Environment with the following commands: $ nix-store --query --requisites /run/current-system | cut -d- -f2- | sort | uniq | grep aide aide-0.18.6 etc-aide.conf $ cat /etc/nixos/configuration.nix | grep -A 5 aide.conf If aide is not installed and is not configured to alert on file system changes, this is a finding.
Fix Text
Configure /etc/nixos/configuration.nix to notify when baseline configuration changes by adding the following configuration settings: nixpkgs.overlays = [ (final: prev: { aide = prev.aide.overrideAttrs (old: { configureFlags = (old.configureFlags or [ ]) ++ [ "--sysconfdir=/etc" ]; }); }) ]; environment.systemPackages = [ pkgs.aide ]; environment.etc = { # Creates /etc/aide.conf "aide.conf" = { text = '' <CONFIG_TEXT> ''; mode = "0444"; }; }; services.cron = { enable = true; systemCronJobs = [ "00 0 * * 0\troot\taide -c /etc/aide.conf --check | /bin/mail -s "aide integrity check run for ${config.networking.hostName}" root@notareal.email" ]; };
Additional Identifiers
Rule ID: SV-268153r1039347_rule
Vulnerability ID: V-268153
Group Title: SRG-OS-000363-GPOS-00150
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-001744 |
Implement organization-defined security responses automatically if baseline configurations are changed in an unauthorized manner. |
| CCI-002696 |
Verify correct operation of organization-defined security functions. |
| CCI-002699 |
Perform verification of the correct operation of organization-defined security functions: when the system is in an organization-defined transitional state; upon command by a user with appropriate privileges; and/or on an organization-defined frequency. |
| CCI-002702 |
Shut the system down, restart the system, and/or initiate organization-defined alternative action(s) when anomalies in the operation of the organization-defined security functions are discovered. |