A vulnerability was found in Samba versions 4.9 and later. During the creation of a new Samba AD DC, files are created in a the private/ subdirectory of our install location. This directory is typically mode 0700, that is owner (root) only access. However in some upgraded installations it will have other permissions, such as 0755, because this was the default before Samba 4.8. Within this directory files are created with mode 0666, that is world-writable, including a sample krb5.conf and the list of DNS names and servicePrincipalName values to update.
Acknowledgments: Name: Björn Baumbach (SerNet)
Statement: This issue did not affect the versions of samba as shipped with Red Hat Enterprise Linux or Red Hat Gluster Storage 3 as they did not include support for Active Directory Domain Controller.
Looking at the spec file, the pysmbd code is packages in RHEL 7. It is probably not used by anything, but it is there. See http://pkgs.devel.redhat.com/cgit/rpms/samba/tree/samba.spec?h=rhel-7.6#n2042
nullIn reply to comment #5: > Looking at the spec file, the pysmbd code is packages in RHEL 7. It is > probably not used by anything, but it is there. See > > http://pkgs.devel.redhat.com/cgit/rpms/samba/tree/samba.spec?h=rhel-7.6#n2042 We do build pysmbd, but afaict the affected code belongs to python/samba/provision/ which is packaged as python-dc. python-dc is only built if %{with_dc} is enabled, which is not presently the case on Red Hat Enterprise Linux. We'll file a tracker for Fedora when this goes public.
External References: https://bugzilla.samba.org/show_bug.cgi?id=13834 https://www.samba.org/samba/security/CVE-2019-3870.html
Created samba tracking bugs for this issue: Affects: fedora-29 [bug 1697718]