LDAP allows null bases

It is possible to disclose LDAP information. Description : Improperly configured LDAP servers will allow the directory BASE to be set to NULL. This allows information to be culled without any prior knowledge of the directory structure. Coupled with a NULL BIND, an anonymous user can query your LDAP server using a tool such as 'LdapMiner'
Disable NULL BASE queries on your LDAP server