William,
I do apologize! I'll keep that in mind in the future.
Thanks again for your help,
Trevor
On Fri, Apr 23, 2021, 7:50 PM William Brown <wbrown@suse.de> wrote:
Sorry to call this out, but my name is "William" not "Bill". I have personal reasons to dislike being called that name.
Regardless, happy to help out :)
> On 23 Apr 2021, at 22:11, Trevor Vaughan <tvaughan@onyxpoint.com> wrote:
>
> Bill and Pierre,
>
> Thanks for the responses!
>
> It sounds like I have to figure out how to configure the NSS library for 389-DS specifically.
>
> In EL8+ I know that I can configure the global crypto policy but I'm hoping that I can do it for the specific application. I haven't found anything in the documentation so far but at least this gets me pointed in the right direction.
>
> Thanks,
>
> Trevor
>
> On Fri, Apr 23, 2021 at 4:42 AM Pierre Rogier <progier@redhat.com> wrote:
> Hi Trevor,
>
> I do not think it is possible to specify the cypher order negotiation:
> I am not sure whether TLS protocol allow to specify an order when negotiating the cypher,
> but at 389 level there is no way to specify an order:
> The NSS security layer provides the list of supported cypher and 389 use
> nsSSL3Ciphers config parameter to enable/disable theses cyphers in the list (without changing the order)
>
> So my feeling is that if there is an order it is up to the different
> security layer implementations and may differs between the applications,
>
> Regards,
> Pierre
>
> On Thu, Apr 22, 2021 at 7:28 PM Trevor Vaughan <tvaughan@onyxpoint.com> wrote:
> Hi William,
>
> In terms of the STARTTLS bits (in theory) properly configuring your client software mitigates the password leak risk. But this also happens with pure (non-RFC) LDAPS connections.
>
> The docs note that minssf applies to the crypto required bits as well as the SASL layer.
>
> Ignoring most of that, my issue is that I don't understand why I have to nail my client software to ciphers explicitly known by 389-DS instead of the two negotiating the strongest things possible out of the gate.
>
> For instance, if I use AES256 with a minssf=256, everything works just fine.
>
> But, if I use AES128:AES256:@STRENGTH (which should sort strongest to weakest) then access is denied.
>
> How do I get 389-DS to negotiate the strongest ciphers first (regardless of the method)?
>
> Thanks,
>
> Trevor
>
> On Wed, Apr 21, 2021 at 7:34 PM William Brown <wbrown@suse.de> wrote:
> Hi there,
>
> > On 22 Apr 2021, at 03:52, Trevor Vaughan <tvaughan@onyxpoint.com> wrote:
> >
> > Hi All,
> >
> > OS Version: CentOS 8
> > 389-DS Version: 1.4.3.22 from EPEL
> >
> > I have a server set up with minssf=256 and have been surprised that either 389-DS, or openssl, does not appear to be doing what I would consider a logical TLS negotiation.
> >
> > I had thought that the system would start with the strongest cipher and then negotiate down to something that was acceptable.
> >
> > Instead, I'm finding that I have to nail up the ciphers to something that the 389-DS server both recognizes and is within the expected SSF.
> >
> > Is this expected behavior or do I have something configured incorrectly?
>
> That's not what minssf does.
>
> minssf says "during a bind operation, reject if the encryption strength used is less than 256 bits or equivalent".
>
> The "bit strength" is arbitrary though, because it's a concept from sasl, and generally is very broken.
>
> Remember, minssf does NOT do what you think though! Because bind is the *first* message on the wire, the series of operations is
>
>
> client server
> open plain text conn ->
> <- accept connection
> send bind on conn ->
> <- reject due to minsff too weak.
>
>
> So you have already leaked the password!
>
>
> The only way to ensure this does not occur is to set "nsslapd-port: 0" which disables plaintext. Then you *only* use ldaps on port 636, which is guarantee encrypted from the start.
>
> It is worth noting that the use of starttls over ldap, does *NOT* mitigate this issue, for a similar reason.
>
>
> Caveat: If you are using kerberos/gssapi you can NOT disable plaintext ldap due to these protocols attempting to install their own encryption layers.
>
>
> Hope that helps,
>
>
> >
> > Thanks,
> >
> > Trevor
> >
> > --
> > Trevor Vaughan
> > Vice President, Onyx Point, Inc
> > (410) 541-6699 x788
> >
> > -- This account not approved for unencrypted proprietary information --
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> —
> Sincerely,
>
> William Brown
>
> Senior Software Engineer, 389 Directory Server
> SUSE Labs, Australia
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>
> --
> Trevor Vaughan
> Vice President, Onyx Point, Inc
> (410) 541-6699 x788
>
> -- This account not approved for unencrypted proprietary information --
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>
> --
> --
>
> 389 Directory Server Development Team
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>
> --
> Trevor Vaughan
> Vice President, Onyx Point, Inc
> (410) 541-6699 x788
>
> -- This account not approved for unencrypted proprietary information --
> _______________________________________________
> 389-users mailing list -- 389-users@lists.fedoraproject.org
> To unsubscribe send an email to 389-users-leave@lists.fedoraproject.org
> Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
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—
Sincerely,
William Brown
Senior Software Engineer, 389 Directory Server
SUSE Labs, Australia
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