Hi folks, at first: thanks very much for the great piece of software!
I have a proposal to tighten the TLS security: enable the usage of a specific
ec-curve in the 10-ssl.conf, e.g.
ssl_ec-curve = secp384r1
Reason: I use a 384 bit EC server key, but dovecot uses "only" a
prime256v1 curve.
Keygen was:
f=dovecot; openssl ecparam -name secp384r1 -genkey -out $f.key
openssl req -new -x509 -key $f.key -out ${f}.crt -days 2000 -sha512
Server check gives:
prio ciphersuite protocols pfs curves
1 ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1
2 ECDHE-ECDSA-AES128-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1
3 ECDHE-ECDSA-AES128-SHA TLSv1.2 ECDH,P-256,256bits prime256v1
4 ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1
5 ECDHE-ECDSA-AES256-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1
6 ECDHE-ECDSA-AES256-SHA TLSv1.2 ECDH,P-256,256bits prime256v1
Certificate: UNTRUSTED, 384 bit, ecdsa-with-SHA512 signature
$ sudo nano /etc/dovecot/conf.d/10-ssl.conf
ssl = required
ssl_protocols = !SSlv2 !SSLv3 TLSv1.2
ssl_cipher_list =
EECDH+AES128+AESGCM:EECDH+AES256+AESGCM:EECDH+AES128+SHA256:EECDH+AES256+SHA384:EECDH+AES128+SHA:EECDH+AES256+SHA
ssl_prefer_server_ciphers = yes
ssl_key = </etc/dovecot/dovecot.key
ssl_cert = </etc/dovecot/dovecot.crt
OS is arch linux.
Thanks very much,
Martin
On 14.04.2016 20:55, Martin wrote:> Hi folks, at first: thanks very much for the great piece of software! > > I have a proposal to tighten the TLS security: enable the usage of a specific ec-curve in the 10-ssl.conf, e.g. > > ssl_ec-curve = secp384r1 > > > Reason: I use a 384 bit EC server key, but dovecot uses "only" a prime256v1 curve. > > > Keygen was: > f=dovecot; openssl ecparam -name secp384r1 -genkey -out $f.key > openssl req -new -x509 -key $f.key -out ${f}.crt -days 2000 -sha512 > > > Server check gives: > prio ciphersuite protocols pfs curves > 1 ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1 > 2 ECDHE-ECDSA-AES128-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1 > 3 ECDHE-ECDSA-AES128-SHA TLSv1.2 ECDH,P-256,256bits prime256v1 > 4 ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1 > 5 ECDHE-ECDSA-AES256-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1 > 6 ECDHE-ECDSA-AES256-SHA TLSv1.2 ECDH,P-256,256bits prime256v1 > > Certificate: UNTRUSTED, 384 bit, ecdsa-with-SHA512 signature > >Thank you for your suggestion, we will take it under consideration as we are improving security settings for next major release. Aki Tuomi Dovecot oy