Is there a document laying around with suggested settings for locking down OpenLDAP? Such as the following? I'm no ldap expert, and I'm sure you can go much more in depth than this.
disallow bind_v2
disallow bind_anon
disallow bind_anon_cred
disallow bind_anon_dn
access to attrs=userPassword
by self write
access to *
by self write
by dn=".*,o=Scalix" read
by * none
Cheers