Ubuntu 24.04 LTS for PKI-based authentication, must implement a local cache of revocation data in case of the inability to access revocation information via the network.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-270738 | UBTU-24-400380 | SV-270738r1066703_rule | Medium |
| Description |
| Without configuring a local cache of revocation data, there is the potential to allow access to users who are no longer authorized (users with revoked certificates). |
| STIG | Date |
| Canonical Ubuntu 24.04 LTS Security Technical Implementation Guide | 2025-05-16 |
Details
| Check Text (C-74771r1066701_chk) |
| Note: If smart card authentication is not being used on the system, this is not applicable. Verify Ubuntu 24.04 LTS, for PKI-based authentication, uses local revocation data when unable to access it from the network with the following command: $ grep cert_policy /etc/pam_pkcs11/pam_pkcs11.conf | grep -E -- 'crl_auto|crl_offline' cert_policy = ca,signature,ocsp_on,crl_auto; If "cert_policy" is not set to include "crl_auto" or "crl_offline", this is a finding. |
| Fix Text (F-74672r1066702_fix) |
| Configure Ubuntu 24.04 LTS, for PKI-based authentication, to use local revocation data when unable to access the network to obtain it remotely. Add or update the "cert_policy" option in "/etc/pam_pkcs11/pam_pkcs11.conf" to include "crl_auto" or "crl_offline". cert_policy = ca,signature,ocsp_on, crl_auto; If the system is missing an "/etc/pam_pkcs11/" directory and an "/etc/pam_pkcs11/pam_pkcs11.conf", find an example to copy into place and modify accordingly at "/usr/share/doc/libpam-pkcs11/examples/pam_pkcs11.conf.example.gz". |