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The Freak Attack SSL/TLS Vulnerability

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Re: The Freak Attack SSL/TLS Vulnerability

#91

Post by mappu »

teekert wrote: post #84
nodesocket wrote: post #32

We wrote a blog post: The perfect SSL nginx configuration ( http://blog.commando.io/the-perfect-nginx-ssl-configuration/ ) which details all the nginx directives to set to achieve an A+ rating on sslLabs, including mitigation of FREAK, POODLE, and HEARTBLEED.

Hmm, as a novice, capable of setting up fine Drupal/Nginx/mail(Postfix) server I'm kind of shocked to get an F rating on ssllabs with the default, up to date, ssl enabled, Debian/Nginx config... Sounds like something to fix, not? Is there that much need for some forms of backwards compatibility? Are A+ servers badly reachable from older browsers or something? Why would the default be so bad? Somehow, in all my naivet…

I have an up-to-date nginx on wheezy, stock debian packages, no more than just `listen $IP ssl ; ssl_certificate ; ssl_certificate_key` directives and it gets an A on ssllabs.

Do you know exactly what problem you had? It might have been unrelated to debian's presets.

EDIT: a different server with a many-times-upgraded nginx package (but same version) has no `ssl_protocols` in /etc/nginx/nginx.conf and so had SSLv3 enabled. So i agree that this can happen. In my case it's probably a consequence of silent upgrades and `Dpkg::Options::=--force-conf{def,new,old}` choosing to preserve existing config files.

Re: The Freak Attack SSL/TLS Vulnerability

#92

Post by [deleted] »

nodesocket wrote: post #32

We wrote a blog post: The perfect SSL nginx configuration ( http://blog.commando.io/the-perfect-nginx-ssl-configuration/ ) which details all the nginx directives to set to achieve an A+ rating on sslLabs, including mitigation of FREAK, POODLE, and HEARTBLEED.

[deleted]

Re: The Freak Attack SSL/TLS Vulnerability

#93

Post by yuhong »

[deleted] wrote: post #92
nodesocket wrote: post #32

We wrote a blog post: The perfect SSL nginx configuration ( http://blog.commando.io/the-perfect-nginx-ssl-configuration/ ) which details all the nginx directives to set to achieve an A+ rating on sslLabs, including mitigation of FREAK, POODLE, and HEARTBLEED.

[deleted]

You can use 3DES instead of RC4, but this cipher is one of the slowest ones.

Re: The Freak Attack SSL/TLS Vulnerability

#94

Post by tombrossman »

diafygi wrote: post #85
teekert wrote: post #84

Earlier quoted context omitted.

Hmm, as a novice, capable of setting up fine Drupal/Nginx/mail(Postfix) server I'm kind of shocked to get an F rating on ssllabs with the default, up to date, ssl enabled, Debian/Nginx config... Sounds like something to fix, not? Is there that much need for some forms of backwards compatibility? Are A+ servers badly reachable from older browsers or something? Why would the default be so bad? Somehow, in all my naivet…

Here's the how we get an A+ rating[1] for nginx on utilityapi.com: ssl on; ssl_certificate my_ssl.crt; ssl_certificate_key my_ssl.key; ssl_session_timeout 5m; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers EECDH+aRSA+AES256:EDH+aRSA+AES256:EECDH+aRSA+AES128:EDH+aRSA+AES128; ssl_session_cache shared:SSL:50m; ssl_prefer_server_ciphers on; add_header Strict-Transport-Security max-age=63072000; Our configuration doesn'…

You can keep your A+ and add IE8 on XP, plus boost your key exchange to 100%[0], by following Mozilla's TLS docs[1] and sticking with the default Intermediate ciphersuite.

You might also consider disabling server tokens to hide your Nginx version (server_tokens off;) for a bit of 'security through obscurity' and enabling SPDY (listen 443 ssl spdy;) for a performance boost.

Also worth pointing out is the upcoming Let's Encrypt project[2] which will make domain validated certificates free soon.

[0]https://www.ssllabs.com/ssltest/analyze.html?d=brossmanit.co... [1]https://wiki.mozilla.org/Security/Server_Side_TLS [2]https://letsencrypt.org/

Re: The Freak Attack SSL/TLS Vulnerability

#95

Post by teekert »

mappu wrote: post #91
teekert wrote: post #84

Earlier quoted context omitted.

Hmm, as a novice, capable of setting up fine Drupal/Nginx/mail(Postfix) server I'm kind of shocked to get an F rating on ssllabs with the default, up to date, ssl enabled, Debian/Nginx config... Sounds like something to fix, not? Is there that much need for some forms of backwards compatibility? Are A+ servers badly reachable from older browsers or something? Why would the default be so bad? Somehow, in all my naivet…

I have an up-to-date nginx on wheezy, stock debian packages, no more than just `listen $IP ssl ; ssl_certificate ; ssl_certificate_key` directives and it gets an A on ssllabs. Do you know exactly what problem you had? It might have been unrelated to debian's presets. EDIT: a different server with a many-times-upgraded nginx package (but same version) has no `ssl_protocols` in /etc/nginx/nginx.conf and so had SSLv3 en…

These are the ones pulling down the grade: - This server is vulnerable to the POODLE attack. If possible, disable SSL 3 to mitigate. Grade capped to C. MORE INFO » - This server supports anonymous (insecure) suites (see below for details). Grade set to F. - The server supports only older protocols, but not the current best TLS 1.2. Grade capped to B. - This server accepts the RC4 cipher, which is weak. Grade capped to B. MORE INFO »

The server was installed quite some time ago on Digital Ocean, it could be that I just need the most recent default Nginx configs. I'll test. Btw, I have a startssl cert, should have choosen the www subdomain though, not "mail". I'll do an apt-get purge nginx before reinstalling and than manually add back the old settings.

Re: The Freak Attack SSL/TLS Vulnerability

#97

Post by exo762 »

diltonm wrote: post #58
LeafStorm wrote: post #49

Earlier quoted context omitted.

> support unauthorized vulnerability attempts That was probably just a random student who learned some fun stuff in Security class and slept through the Ethics lesson. I can't speak for UMich, but security research at my university (NC State) has a very strict "don't attack civilians" policy. > hosting a .com commercial site First off, .com sites are not necessarily commercial. Second, this isn't a commercial site, i…

In the first case I read you as saying it's OK to commit a crime against a civilian in the United States as long as [the person didn't mean to] and in the second case that since not all .COM domains are used for commercial purposes and since this one seems to be information only at the moment; that our tax dollars which helps Universities across the United States to run can be used to fund whatever .COM sites student…

I heard that rhetoric when ones you are calling for help prosecuted Aaron Schwartz. All in times when NSA was hacking all the systems they could get their hands on both around the world and in USA.

You may be overreacting and unwillingly supporting erosion of civil rights.

Re: The Freak Attack SSL/TLS Vulnerability

#98

Post by higherpurpose »

tombrossman wrote: post #94
diafygi wrote: post #85

Earlier quoted context omitted.

Here's the how we get an A+ rating[1] for nginx on utilityapi.com: ssl on; ssl_certificate my_ssl.crt; ssl_certificate_key my_ssl.key; ssl_session_timeout 5m; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers EECDH+aRSA+AES256:EDH+aRSA+AES256:EECDH+aRSA+AES128:EDH+aRSA+AES128; ssl_session_cache shared:SSL:50m; ssl_prefer_server_ciphers on; add_header Strict-Transport-Security max-age=63072000; Our configuration doesn'…

You can keep your A+ and add IE8 on XP, plus boost your key exchange to 100%[0], by following Mozilla's TLS docs[1] and sticking with the default Intermediate ciphersuite. You might also consider disabling server tokens to hide your Nginx version (server_tokens off;) for a bit of 'security through obscurity' and enabling SPDY (listen 443 ssl spdy;) for a performance boost. Also worth pointing out is the upcoming Let'…

I think using Mozilla's "Modern cipher suite" list should do it, and it seems to be all forward secure:

https://wiki.mozilla.org/Security/Server_Side_TLS#Modern_com...

Re: The Freak Attack SSL/TLS Vulnerability

#99

Post by tombrossman »

higherpurpose wrote: post #98
tombrossman wrote: post #94

Earlier quoted context omitted.

You can keep your A+ and add IE8 on XP, plus boost your key exchange to 100%[0], by following Mozilla's TLS docs[1] and sticking with the default Intermediate ciphersuite. You might also consider disabling server tokens to hide your Nginx version (server_tokens off;) for a bit of 'security through obscurity' and enabling SPDY (listen 443 ssl spdy;) for a performance boost. Also worth pointing out is the upcoming Let'…

I think using Mozilla's "Modern cipher suite" list should do it, and it seems to be all forward secure: https://wiki.mozilla.org/Security/Server_Side_TLS#Modern_com...

What prevents me from using 'Modern' is it requires Android 4.4+, which excludes a hell of a lot of mobile users. I'm okay with dropping XP support but dropping Android 4.3 and earlier is too limiting for me.

Re: The Freak Attack SSL/TLS Vulnerability

#100

Post by sschueller »

nodesocket wrote: post #32

We wrote a blog post: The perfect SSL nginx configuration ( http://blog.commando.io/the-perfect-nginx-ssl-configuration/ ) which details all the nginx directives to set to achieve an A+ rating on sslLabs, including mitigation of FREAK, POODLE, and HEARTBLEED.

If you want 100% on all categories (not recommend, you will prevent a lot of browser from using SSL) you will need to turn off everything other than TLS 1.2 and remove all ciphers that are lower than 256 bits. You will also need a 4096 bits certificate with SHA256.

  ssl on;
  ssl_certificate      ssl.nginx;
  ssl_certificate_key  ssl.key;
  ssl_dhparam dhparam.pem;
  ssl_protocols TLSv1.2;
  ssl_prefer_server_ciphers on;
  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-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:!AES128-SHA256:!DES-CBC3-SHA:!CAMELLIA128-SHA:!DHE-RSA-CAMELLIA128-SHA';
  ssl_session_cache    shared:SSL:10m;
  ssl_session_timeout  10m;
https://www.ssllabs.com/ssltest/analyze.html?d=techdroid.com
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