Review default ssl ciphers for GitLab.com

From what I remember, we are still using ciphers to support some old java IDE's. @briann is it maybe worth reviewing our cipher list to see if we can improve it further? Also, can we somehow automate ssl cipher checking so we don't get reports about weak ciphers but do it proactive from our side?

cc @jnijhof

We recently ran a vulnerability scan that checked for weak ciphers. @northrup also ran a check with Qualsys. The vulnerability scan shows these ciphers as being weak:

TLS1_ECDHE_RSA_WITH_DES_192_CBC3_SHA TLS1_RSA_DES_192_CBC3_SHA TLS1_ECDHE_RSA_WITH_DES_192_CBC3_SHA TLS1_RSA_DES_192_CBC3_SHA TLS_1_2_RSA_WITH_3DES_EDE_CBC_SHA

I believe these are all BEAST/CBC vulnerable ciphers. The alternative is RC4 which has problems of its own. Modern browsers have protections against BEAST so both Mozilla and Microsoft recommend keeping CBC ciphers over RC4.

Meanwhile @northrup's scan says we get an A for SSL cipher configuration.

https://www.ssllabs.com/ssltest/analyze.html?d=gitlab.com

@briann @marin

The new proposed configuration is as follows:

    ssl_session_cache builtin:1000 shared:SSL:10m;
    ssl_session_timeout 5m;
    ssl_prefer_server_ciphers on;
    ssl_ciphers ECDH+AESGCM:ECDH+AES256:ECDH+AES128:DH+3DES:!ADH:!AECDH:!MD5;
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_stapling on;
    ssl_stapling_verify on;

@marin can anyone reference where the legacy support for ultra weak ciphers for JAVA IDE's comes from? The most recent releases of JAVA don't even support those weak cipher sets any more, so I'm 98% we can drop them.

@northrup It took me a while trust me but I think I found the original issue where this was discussed: https://gitlab.com/gitlab-org/gitlab-ce/issues/624

Added security label

marked this issue as related to gitlab-org/omnibus-gitlab#2666 (closed)