NixOS must prohibit the use of cached authenticators after one day.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-268178 | SRG-OS-000383-GPOS-00166 | ANIX-00-002050 | SV-268178r1131164_rule | 2025-08-19 | 1 |
Description
If cached authentication information is out-of-date, the validity of the authentication information may be questionable.
ℹ️ Check
Verify NixOS, for PKI-based authentication, only caches authenticators for one day with the following command:
$ sudo grep expiration /etc/sssd/sssd.conf
offline_credentials_expiration = 1
If the offline_credentials_expiration is not set to "1" or is commented out, this is a finding.
✔️ Fix
Configure NixOS to prohibit the use of cached credentials older than one day.
Add the following Nix code to the NixOS Configuration, usually located in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:
Note: The entire sssd.conf must be entered in this option.
services.sssd.config = ''
...
[pam]
offline_credentials_expiration = 1
...
'';
Rebuild and switch to the new NixOS configuration:
$ sudo nixos-rebuild switch