Ubuntu 24.04 LTS must use DoW PKI-established certificate authorities (CAs) for verification of the establishment of protected sessions.

Untrusted CAs can issue certificates, but they may be issued by organizations or individuals that seek to compromise DoW systems or by organizations with insufficient security controls. If the CA used for verifying the certificate is not a DoW-approved CA, trust of this CA has not been established.

The DoW will only accept PKI-certificates obtained from a DoW-approved internal or external certificate authority. Reliance on CAs for the establishment of secure sessions includes, for example, the use of SSL/TLS certificates.

Verify the directory containing the root certificates for Ubuntu 24.04 LTS contains certificate files for DoW PKI-established CAs by iterating over all files in the "/etc/ssl/certs" directory and checking if, at least one, has the subject matching "DOD ROOT CA".

$ grep -ir DoW /etc/ssl/certs DoW_PKE_CA_chain.pem

If no root certificate is found, this is a finding.

Configure Ubuntu 24.04 LTS to use of DoW PKI-established CAs for verification of the establishment of protected sessions.

Edit the "/etc/ca-certificates.conf" file, adding the character "!" to the beginning of all uncommented lines that do not start with the "!" character with the following command:

$ sudo sed -i -E 's/^([^!#]+)/!\1/' /etc/ca-certificates.conf 

Add at least one CA to the "/usr/local/share/ca-certificates" directory in the PEM format.

Update the "/etc/ssl/certs" directory with the following command:

$ sudo update-ca-certificates