NixOS must prevent all software from executing at higher privilege levels than users executing the software.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-268148	SRG-OS-000326-GPOS-00126	ANIX-00-001280	SV-268148r1039332_rule	2024-10-25	1

Description
In certain situations, software applications/programs need to execute with elevated privileges to perform required functions. However, if the privileges required for execution are at a higher level than the privileges assigned to organizational users invoking such applications/programs, those users are indirectly provided with greater privileges than assigned by the organizations. Some programs and processes are required to operate at a higher privilege level and therefore should be excluded from the organization-defined software list after review.

Description

In certain situations, software applications/programs need to execute with elevated privileges to perform required functions. However, if the privileges required for execution are at a higher level than the privileges assigned to organizational users invoking such applications/programs, those users are indirectly provided with greater privileges than assigned by the organizations. Some programs and processes are required to operate at a higher privilege level and therefore should be excluded from the organization-defined software list after review.

ℹ️ Check
Verify NixOS audits and provides alerts of audit failures by running the following command: $grep A -15 security.auditd /etc/nixos/configuration.nix /etc/nixos/configuration.nix: security.auditd.enable = true; security.audit.enable = true; security.audit.rules = [ '' <audit_rules> '' ]; security.audit.rules = [ "-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv" ]; If "security.auditd", "security.audit" and the additional modifications do not equal true, are missing, or are commented out, this is a finding.

ℹ️ Check

Verify NixOS audits and provides alerts of audit failures by running the following command: $grep A -15 security.auditd /etc/nixos/configuration.nix /etc/nixos/configuration.nix: security.auditd.enable = true; security.audit.enable = true; security.audit.rules = [ '' <audit_rules> '' ]; security.audit.rules = [ "-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv" ]; If "security.auditd", "security.audit" and the additional modifications do not equal true, are missing, or are commented out, this is a finding.

✔️ Fix
Configure the audit service to produce audit records. Install the audit service (if the audit service is not already installed) and ensure the audit service is enabled by adding or updating the following configurations in /etc/nixos/configuration.nix: security.auditd.enable = true; security.audit.enable = true; Additionally, add the following audit rules: security.audit.rules = [ "-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv" ]; Then, rebuild the NixOS configuration with the following command: $ sudo nixos-rebuild switch

✔️ Fix

Configure the audit service to produce audit records. Install the audit service (if the audit service is not already installed) and ensure the audit service is enabled by adding or updating the following configurations in /etc/nixos/configuration.nix: security.auditd.enable = true; security.audit.enable = true; Additionally, add the following audit rules: security.audit.rules = [ "-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv" "-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv" "-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv" ]; Then, rebuild the NixOS configuration with the following command: $ sudo nixos-rebuild switch