Red Hat Security Advisory 2017-0494-01 – Samba is an open-source implementation of the Server Message Block protocol and the related Common Internet File System protocol, which allow PC-compatible machines to share files, printers, and various information. The following packages have been upgraded to a later upstream version: samba. Security Fix: It was found that Samba always requested forwardable tickets when using Kerberos authentication. A service to which Samba authenticated using Kerberos could subsequently use the ticket to impersonate Samba to other services or domain users.