samba4: privilege escalation

From the Red Hat bugzilla entry:

Samba 4.0 as an AD DC may provide authenticated users with write access to LDAP directory objects.

In AD, Access Control Entries can be assigned based on the objectClass of the object. If a user or a group the user is a member of has any access based on the objectClass, then that user has write access to that object.

Additionally, if a user has write access to any attribute on the object, they may have access to write to all attributes.