Let’s Encrypt Wildcard Certs

Recently Let’s Encrypt announced that they would be supporting wildcard certs. I was pretty excited to hear about this as many times I would like to get certs for machines that might not be accessible on the internet. Currently I didn’t see an easy way to do this. With the new certs you could get a cert on your web server for your domain and use that cert on all the other machines in your domain that need TLS as well.

I decided to try it out and see how easy it was to do. I updated my certbot client to version 0.22 and did some google around and found out that you have to specify the new acme version 2 servers on the client command line in order to generate the wildcard cert. So I found the command and fired it up:

./certbot-auto --server https://acme-v02.api.letsencrypt.org/directory -d *.haskovec.com --manual --preferred-challenges dns-01 certonly

The command runs and asks you a few questions and then presents a DNS challenge. They give you a TXT record that you need to update in your DNS server to prove that you control the domain. I added the record and waited a couple of minutes and next thing you know it generated my new cert.

I updated my NGINX config to point to the new cert restarted the server and hit my site. Next thing I see is an SSL error. It turns out if you only have *.haskovec.com in the cert that isn’t a valid server for the base domain of haskovec.com. So I reran the command again and specified the following:

 ./certbot-auto --server https://acme-v02.api.letsencrypt.org/directory -d haskovec.com -d *.haskovec.com --manual --preferred-challenges dns-01 certonly

This time it asked me if I want to expand my cert to include the new domain name. I said yes. Next it had 2 challenges that I needed to insert into my DNS TXT record. I added them both and finished generating the new cert. When I restarted NGINX my site was back. I ran the https://www.ssllabs.com/ security test on my site and I am still at an A+.

All in all a very easy process and I recommend people give it a try.

Speaking of security…

Today I came across the following news.┬áThe Chrome security team is considering marking all non-HTTPS sites as insecure (since they are.)┬áCheck out the story here. What this means is that if you don’t setup SSL on your site you are likely to lose users who are going to fear if your site is safe to use. Google has already announced that they are going to score pages higher in their search index if they use encryption and this is just more incentive for people to take the time to secure their sites. In 2014 it no longer makes sense to run a non-encrypted website. Techdirt also covered the story here.

Update
I forgot to mention you can get free SSL certificates at Start SSL so price isn’t an excuse for not upgrading your site.

Security is about tradeoffs

When I was working on this site on of the first things I did after setting up SSL was to run the Qualys SSL Labs Test on my site. This tool will analyze your site security and point out any weaknesses and assign a grade to your site. I initially scored a C and used the test results to get this site up to an A. When I got to an A I thought I was doing well as I had robust forward secrecy and my scores 100, 95, 80, 90. Then I saw this blog post over here and noticed his site while also had an A score he had a key exchange score of 100. This sent me down the rabbit hole of tweaking SSL configs to figure out how to really get a high score on this test.

After hours of testing I determined the difference was disabling the kEDH Ciphers which are “cipher suites using ephemeral DH key agreement, including anonymous cipher suites.” Once those are disabled my key exchange score went up to 100, however I lost my robust forward secrecy rating. There is the tradeoff if you drop those ciphers there are a bunch of devices out there that can’t do forward secrecy anymore, but if you keep them you are using what are considered to be weaker ciphers. In the end I decided to drop them, and then since I was in there I continued tweaking to one up Christopher Burg and got my site all the way up to an A+ before his. Who says a little friendly competition isn’t good motivation.

For anyone who is curious I looked into what it would take to get all 100s on the test and it is a price I am unwilling to pay at this time. Basically you have to run only TLS1.2 and have things really locked down. The other thing I would like to figure out is are the Camellia ciphers good and considered secure? I saw some sites recommending them, but I haven’t really heard much about them. I would love to know what the security community thinks of them, whether they are considered secure or efficient. I considered testing with them, against the Qualys SSL report card but it was midnight when I finally got to my A+ so I just left things where they were. If you want to check out my score on the test go here. Also check out this lovely image of my report card:

ssl-reportcard

PGP and the trouble with the web of trust

I have been a fan of Pretty Good Privacy and Gnu Privacy Guard for years. It was just a great idea and I would love to see it more widely used. One problem PGP has always had is the learning curve and ease of use. It used to be very difficult to integrate it into your email. Today it is easier to use with plugins for Thunderbird and other mail apps.

One of the greatest weaknesses of PGP from way back in the day until today is key exchange and how to know you have a valid key for someone you are trying to contact. We have key servers where you can search for a key for someone’s email address, but again you have the issue of how do you know that the person you are contacting actually posted that key and it isn’t an adversary who is pretending to be that user. Back in the day there used to be discussions of key signing parties and other things that just didn’t seem practical. I think my PGP key has been signed by 1 user. Then along comes Keybase. This seems to solve the big issue with PGP which is how to find a key for someone and how to know you can trust that key. Now if someone follows me on Twitter and this website they can see that Keybase has validated my PGP key against ownership of this domain and my twitter account among other things finally solving the issue.

Now we finally have better tools for PGP, and the world has moved on to web mail which makes it much more difficult to encrypt end to end again. Anyway if Keybase sounds interesting to you, you can find me here. If anyone wants an invite to it send me a request for an invite on twitter.