MNBSD-2023-6 pam_krb5 blindly validates messages when no keytab is provided.

pam_krb5 authenticates the user by essentially running kinit(1) 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. Normally, the system running the pam_krb5 module will also have a keytab, a key provisioned by the KDC. The pam_krb5 module will use the tgt to get a service ticket and validate it against the keytab, ensuring the tgt is valid and therefore, the password is valid. 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.

Aliases: FreeBSD-SA-23:09.pam_krb5

Modified: 2023-08-09T00:00:00.000Z
Published: 2023-08-09T00:00:00.000Z