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

NixOS must generate audit records when successful/unsuccessful attempts to modify security objects occur.

DISA Rule

SV-268163r1131131_rule

Vulnerability Number

V-268163

Group Title

SRG-OS-000463-GPOS-00207

Rule Version

ANIX-00-001720

Severity

CAT II

CCI(s)

• CCI-000172 - Generate audit records for the event types defined in AU-2 c that include the audit record content defined in AU-3.
• CCI-000135 - Generate audit records containing the organization-defined additional information that is to be included in the audit records.

Weight

10

Fix Recommendation

Configure NixOS to log attempts to modify security objects.

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

security.audit.rules = [
"-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod"
"-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod"
"-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod"
"-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod"
];

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

Check Contents

Verify the NixOS generates audit records when successful/unsuccessful attempts to modify security objects occur with the following command:

$ sudo auditctl -l | grep xattr

-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod
-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod
-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod
-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod

If the command does not return an audit rule for "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr", this is a finding.

Vulnerability Number

V-268163

Documentable

False

Rule Version

ANIX-00-001720

Severity Override Guidance

Verify the NixOS generates audit records when successful/unsuccessful attempts to modify security objects occur with the following command:

$ sudo auditctl -l | grep xattr

-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod
-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod
-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=-1 -k perm_mod
-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod

If the command does not return an audit rule for "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr", this is a finding.

Check Content Reference

M

Target Key

5658