Rule ID
SV-268153r1131108_rule
Version
V1R2
CCIs
CCI-001744, CCI-002696, CCI-002699, CCI-002702
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
Verify NixOS notifies if baseline configurations are changed with Advanced Intrusion Detection Environment with the following commands: $ systemctl is-active aide.service active If aide is not active and is not configured to alert on file system changes, this is a finding.
Configure NixOS to notify when baseline configuration changes.
Add the following Nix code to the NixOS Configuration, usually located in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:
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"
];
};
Rebuild and switch to the new NixOS configuration:
$ sudo nixos-rebuild switch