STIGQter: STIG Summary: Anduril NixOS Security Technical Implementation Guide Version: 1 Release: 2 Benchmark Date: 01 Oct 2025:

NixOS must implement cryptographic mechanisms to protect the integrity of nonlocal maintenance and diagnostic communications, when used for nonlocal maintenance sessions.

DISA Rule

SV-268157r1131119_rule

Vulnerability Number

V-268157

Group Title

SRG-OS-000393-GPOS-00173

Rule Version

ANIX-00-001550

Severity

CAT I

CCI(s)

• CCI-002890 - Implement organization-defined cryptographic mechanisms to protect the integrity of nonlocal maintenance and diagnostic communications.

Weight

10

Fix Recommendation

Configure /etc/nixos/configuration.nix to use the following FIPS 140-3 approved MAC codes in openssh.

Add the following Nix code to the NixOS Configuration, usually located in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:

services.openssh.macs = [
"hmac-sha2-512"
"hmac-sha2-256"
];

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

Check Contents

Verify NixOS uses the following FIPS 140-3 approved MAC codes in openssh with the following command:

$ grep Mac /etc/ssh/sshd_config

Macs hmac-sha2-512 hmac-sha2-256

If "Macs" contains any ciphers other than "hmac-sha2-512" or "hmac-sha2-256", this is a finding.

Vulnerability Number

V-268157

Documentable

False

Rule Version

ANIX-00-001550

Severity Override Guidance

Verify NixOS uses the following FIPS 140-3 approved MAC codes in openssh with the following command:

$ grep Mac /etc/ssh/sshd_config

Macs hmac-sha2-512 hmac-sha2-256

If "Macs" contains any ciphers other than "hmac-sha2-512" or "hmac-sha2-256", this is a finding.

Check Content Reference

M

Target Key

5658