|Finding ID||Version||Rule ID||IA Controls||Severity|
|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).|
|Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide||2022-12-06|
|Check Text ( C-41443r653872_chk )|
| Verify the Ubuntu operating system, for PKI-based authentication, uses local revocation data when unable to access it from the network. |
Verify that "crl_offline" or "crl_auto" is part of the "cert_policy" definition in "/etc/pam_pkcs11/pam_pkcs11.conf" using the following command:
# sudo 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-41402r880869_fix)|
| Configure the Ubuntu operating system, 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".