Vulnerability Discussion

Without mapping the certificate used to authenticate to the user account, the ability to determine the identity of the individual user or group will not be available for forensic analysis.

There are various methods of mapping certificates to user/group accounts for RHEL 8. For the purposes of this requirement, the check and fix will account for Active Directory mapping. Some of the other possible methods include joining the system to a domain and utilizing a Red Hat idM server, or a local system mapping, where the system is not part of a domain.

Check

Verify the certificate of the user or group is mapped to the corresponding user or group in the "sssd.conf" file with the following command:

$ sudo cat /etc/sssd/sssd.conf

[sssd]
config_file_version = 2
services = pam, sudo, ssh
domains = testing.test

[pam]
pam_cert_auth = True

[domain/testing.test]
id_provider = ldap

[certmap/testing.test/rule_name]
matchrule =.*EDIPI@mil
maprule = (userCertificate;binary={cert!bin})
domains = testing.test

If the certmap section does not exist, ask the System Administrator to indicate how certificates are mapped to accounts. If there is no evidence of certificate mapping, this is a finding.

Fix

Configure the operating system to map the authenticated identity to the user or group account by adding or modifying the certmap section of the "/etc/sssd/sssd.conf file based on the following example:

[certmap/testing.test/rule_name]
matchrule =.*EDIPI@mil
maprule = (userCertificate;binary={cert!bin})
dmains = testing.test

The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command:

$ sudo systemctl restart sssd.service