Diffie-Hellman Security

To secure your web server, the Guide to Deploying Diffie-Hellman for TLS contains important information worth reading. This link contains a good nginx secure configuration example. The documentation below also contains good security settings with some additional |RCE| specific examples.

To secure your deployment of Diffie-Hellman, configure the following:

• Generate a strong Diffie-hellman group, 2048-bit or stronger.

# to generate your dhparam.pem file, run in the terminal
openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048

• Configure your server to only use modern, secure cipher suites in the virtual hosts configuration file.

# Set the TLS protocols and to only use modern, secure cipher suites.
ssl_ciphers "ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4";
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;

# Diffie-Hellman parameter for DHE ciphersuites, recommended 2048 bits
ssl_dhparam /etc/nginx/ssl/dhparam.pem;