CVE-2023-3326

pam_krb5 authenticates a user by essentially running kinit with the
password, getting a ticket-granting ticket (tgt) from the Kerberos KDC (Key
Distribution Center) over the network, as a way to verify the password.
However, if a keytab is not provisioned on the system, pam_krb5 has no way
to validate the response from the KDC, and essentially trusts the tgt
provided over the network as being valid. In a non-default FreeBSD
installation that leverages pam_krb5 for authentication and does not have a
keytab provisioned, an attacker that is able to control both the password
and the KDC responses can return a valid tgt, allowing authentication to
occur for any user on the system.

Notes