Strengthen nginx SSL configuration

roles/webserver/defaults/main.yml

@@ -8,6 +8,7 @@ with_apache2_modphp5: False
 with_nginx: False
 # nginx_workers ~= $(getconf _NPROCESSORS_ONLN)
 nginx_workers: 2
+nginx_ssl_strengthened: False
 
 with_fpm: False
 fpm_pool_count: 1

roles/webserver/templates/nginx/nginx.conf.j2

@@ -135,27 +135,33 @@ http {
         text/x-component;
     # text/html is always compressed by HttpGzipModule
 
-
-    ### SSL ###
-
     # This should be turned on if you are going to have pre-compressed copies (.gz) of
     # static files available. If not it should be left off as it will cause extra I/O
     # for the check. It is best if you enable this in a location{} block for
     # a specific directory, or on an individual server{} level.
     # gzip_static on;
 
-    # Protect against the BEAST attack by preferring RC4-SHA when using SSLv3 and TLS protocols.
-    # Note that TLSv1.1 and TLSv1.2 are immune to the beast attack but only work with OpenSSL v1.0.1 and higher and has limited client support.
-    ssl_protocols              SSLv3 TLSv1 TLSv1.1 TLSv1.2;
-    ssl_ciphers                RC4:HIGH:!aNULL:!MD5;
+
+    ### SSL ###
+
+    # Diffie-Hellman parameter for DHE ciphersuites
+    ssl_dhparam /etc/ssl/private/dh2048.pem;
+
+{% if nginx_ssl_strengthened %}
+    ssl_protocols   TLSv1.1 TLSv1.2;
+    ssl_ciphers     'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK';
+{% else %}
+    ssl_protocols   TLSv1 TLSv1.1 TLSv1.2;
+    ssl_ciphers     'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA';
+{% endif %}
     ssl_prefer_server_ciphers  on;
 
-    # Optimize SSL by caching session parameters for 10 minutes. This cuts down on the number of expensive SSL handshakes.
+    # Optimize SSL by caching session parameters for 5 minutes. This cuts down on the number of expensive SSL handshakes.
     # The handshake is the most CPU-intensive operation, and by default it is re-negotiated on every new/parallel connection.
     # By enabling a cache (of type "shared between all Nginx workers"), we tell the client to re-use the already negotiated state.
     # Further optimization can be achieved by raising keepalive_timeout, but that shouldn't be done unless you serve primarily HTTPS.
     ssl_session_cache    shared:SSL:10m; # a 1mb cache can hold about 4000 sessions, so we can hold 40000 sessions
-    ssl_session_timeout  10m;
+    ssl_session_timeout  5m;
 
     # This default SSL certificate will be served whenever the client lacks support for SNI (Server Name Indication).
     # Make it a symlink to the most important certificate you have, so that users of IE 8 and below on WinXP can see your main site without SSL errors.
@@ -168,12 +174,6 @@ http {
     #passenger_root /usr;
     #passenger_ruby /usr/bin/ruby;
 
-
-    ### Naxsi ###
-
-    #include /etc/nginx/naxsi_core.rules;
-
-
     ### Extended configuration ###
 
     # More configuration parameters