"A" Grade SSL/TLS with Nginx and StartSSL
julien at linuxwall.info
Tue Oct 15 13:27:17 UTC 2013
On 2013-10-15 00:39, Piotr Sikora wrote:
> Hi Julien,
>> I spent some time hacking on my SSL conf recently. Nothing new, but I
>> figured I'd share it with the group:
>> Feel free to comment here.
>> a few pointers for configuring state-of-the-art TLS on Nginx.
> Far from it, from the top:
> You should be using:
> instead of compiling OpenSSL yourself and playing with CFLAGS & LDFLAGS.
Afaik, the above dynamically links openssl. Am I wrong?
>> listen 443;
>> ssl on;
> That's deprecated syntax, you should be using:
> listen 443 ssl;
noted, but that doesn't impact security
>> ssl_dhparam /path/to/dhparam.pem;
> While there is nothing wrong with it per se, DH params are only used
> by DHE, which is simply too slow to be used.
Are you saying you would rather use non-PFS ciphers than wait an extra 15ms
to complete a DHE handshake? I wouldn't.
>> ssl_session_timeout 5m;
> Not only doesn't it change anything (5m is the default value), but
> it's way too low value to be used.
> Few examples from the real world:
> Google : 28h
> Facebook : 24h
> CloudFlare: 18h
> Twitter : 4h
Interesting information, which I didn't have before. May I ask how you
>> ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
> SSLv3 is still out there, so you shouldn't be dropping support for it
> unless you know the consequences very well... This definitely
> shouldn't be a general recommendation.
> Why would you put ECDSA cipher suites here when you're using RSA
Because someone else might use DSA certificates.
> You should also disable:
> - DHE cipher suites, because they're too slow compared to the alternative,
No. The alternatives aren't available everywhere.
> - CAMELLIA cipher suites (if you're using AES-NI), because they're too
> slow compared to the alternative.
Again, I don't control clients. I push down unwanted ciphers, but I won't
disable them unless they are obviously broken (MD5, ...).
> Overall, that's far from the state-of-the-art SSL configuration for
> nginx. The only good thing about it is that it's using OCSP and
> achieves "A" grade on ssllabs.com, which can tell you a lot about the
> quality of the tests they're running.
I appreciate the feedback, but no need to be rude about it ;)
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