[Samba] Security Implications of "ldap server require strong auth"?

[Bestattungen Vitt - Thomas Reitelbach]

Am 27.05.2024 16:25, schrieb Rowland Penny via samba:
> On Mon, 27 May 2024 15:57:52 +0200
> Bestattungen Vitt - Thomas Reitelbach via samba <samba at lists.samba.org>
> wrote:
> 
>> Hello Samba Team,
>> 
>> I hope someone with more expertise than me can englighten me to the
>> following "problem":
>> 
>> I'm on my way to implement Nextcloud LDAP Authentication against my
>> existing Samba Active Directory via the LDAP Auth Plugin in
>> Nextcloud. I have had trouble with the configuration of the
>> Auth-Plugin in Nextcloud because it could not bind to the ldap
>> directory. After some investigation I learned, that the nextcloud
>> ldap auth plugin does not support "strong authentication", which
>> seems to be enforced by samba by default.
>> Further investigation led me to the solution to use the [global]
>> option "ldap server require strong auth = no" in smb.conf. With this
>> option set, the ldap plugin is working and my Domain users can
>> authenticate to nextcloud with their Domain account.
>> 
>> But before I implement this in my production system I need to know
>> the security implications of this samba parameter. I must admit that
>> I don't really understand the risc for a real-life scenario. Also,
>> I'm not very experienced with ldap, so please, can you help me a bit?
>> 
>> Samba: 4.17.12-Debian (stock debian version)
>> Nextcloud Hub 8 (29.0.0.1)
>> 
>> Cheers
>> Thomas Reitelbach
>> 
> 
> It is quite simple, 'ldap server require strong auth = no' allows
> simple binds over ldap, 'ldap server require strong auth = yes' (the
> default) requires ldaps.

Hi Rowland,

thank you for your reply and your time.
I am aware that this option enables "simple binds". But what does this 
mean for network security? Maybe I don't understand the meaning of 
"simple binds" -> does it mean, credentials will be sent unencrypted 
over the network and can easily be sniffed by anyone who has access to a 
network scanner/analyzer?
Maybe it's a stupid question, but what I have found with my google 
search does not give me a clue if this option can be safely used in a 
corporate network with at least a bit of security awareness or not.

Usually the samba teams choices for "default" parameters are very 
sensitive and with security in mind. This makes me think it might be a 
bad idea to use "ldap server require strong auth = no".

Cheers
Thomas

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