Hi Aki,
Where do I get testssh.sl? If the script is of your design could you mail it to
me?
Yours
Stefan
________________________________
Von: Aki Tuomi <aki.tu...@open-xchange.com>
Gesendet: Mittwoch, 14. Juli 2021 19:34
An: Stefan Schumacher <s.schumac...@consulting1x1.com>; dovecot@dovecot.org
<dovecot@dovecot.org>
Betreff: Re: TLS Security
> On 14/07/2021 17:55 Stefan Schumacher <s.schumac...@consulting1x1.com> wrote:
>
>
> Hi,
>
>
> I wish to build a new secure email server. It seems I am on the right way –
> at least I get no more error messages for Postfix – but Dovecot is still
> making trouble.
>
>
> I am using Dovecot 1:2.3.4.1-5+deb10u6 and I am using ISPconfig 3.25 to do
> the rough configuring and nano and whats left of my brain to do the finer
> details. Lets start with what I added to conf.d/10-ssl.conf
>
>
> ssl_cert = </etc/letsencrypt/live/servername/fullchain.pem
> ssl_key = </etc/letsencrypt/live/servername/privkey.pem
>
>
> ssl_cipher_list =
> EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aR$
> ssl_protocols = !SSLv2 !SSLv3 !TLSv1 !TLSv1.1
> ssl_min_protocol = TLSv1.2
>
>
> As you can see, I clearly do not want to use TLS before v1.2. I think this is
> not unreasonable in the year 2021.
>
>
> Now, after the changes I ran Kali (I use it to verify the results of my
> experiments)
> and - this is a mailing list, so no screenshots:
> It says:
>
>
> SSL/TLS Deprecated TLS v1.0 and TLS v1.1 Detection. I get this for the ports
> 143, 110, 993 and 995.
>
>
> I thought I had done everything one could to disable old TLS-Versions. What
> am I doing wrong?
>
>
> Yours sincerely
> Stefan Schumacher
>
>
Hi!
First of all, 2.3.4.1 is bit old, and has no proper support for TLSv1.3, which
is supported better on a later version. Now, I installed 2.3.4.1 from debian
10, and tested with testssl.sh and got
SSLv2 not offered (OK)
SSLv3 not offered (OK)
TLS 1 not offered
TLS 1.1 not offered
TLS 1.2 offered (OK)
TLS 1.3 offered (OK): final
NPN/SPDY not offered
ALPN/HTTP2 not offered
TLSv1.2 (no server order, thus listed by strength)
xc030 ECDHE-RSA-AES256-GCM-SHA384 ECDH 521 AESGCM 256
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
xc028 ECDHE-RSA-AES256-SHA384 ECDH 521 AES 256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
xc014 ECDHE-RSA-AES256-SHA ECDH 521 AES 256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
xcca8 ECDHE-RSA-CHACHA20-POLY1305 ECDH 521 ChaCha20 256
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
xc077 ECDHE-RSA-CAMELLIA256-SHA384 ECDH 521 Camellia 256
TLS_ECDHE_RSA_WITH_CAMELLIA_256_CBC_SHA384
xc061 ECDHE-ARIA256-GCM-SHA384 ECDH 521 ARIAGCM 256
TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384
xc02f ECDHE-RSA-AES128-GCM-SHA256 ECDH 521 AESGCM 128
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
xc027 ECDHE-RSA-AES128-SHA256 ECDH 521 AES 128
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
xc013 ECDHE-RSA-AES128-SHA ECDH 521 AES 128
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
xc076 ECDHE-RSA-CAMELLIA128-SHA256 ECDH 521 Camellia 128
TLS_ECDHE_RSA_WITH_CAMELLIA_128_CBC_SHA256
xc060 ECDHE-ARIA128-GCM-SHA256 ECDH 521 ARIAGCM 128
TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256
TLSv1.3 (no server order, thus listed by strength)
x1302 TLS_AES_256_GCM_SHA384 ECDH 253 AESGCM 256
TLS_AES_256_GCM_SHA384
x1303 TLS_CHACHA20_POLY1305_SHA256 ECDH 253 ChaCha20 256
TLS_CHACHA20_POLY1305_SHA256
x1301 TLS_AES_128_GCM_SHA256 ECDH 253 AESGCM 128
TLS_AES_128_GCM_SHA256
I used:
listen = *
mail_attribute_dict = file:%h/Mail/dovecot-attributes
mail_gid = vmail
mail_home = /home/vmail/%Lu
mail_location = sdbox:~/Mail
mail_uid = vmail
passdb {
args = password=#hidden_use-P_to_show#
driver = static
}
protocols = imap
ssl_cert = <cert.pem
ssl_cipher_list =
EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
ssl_min_protocol = TLSv1.2
Aki
