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HTTPS

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HTTPS is an abbreviation for Hypertext Transfer Protocol Secure, a protocol for secure communication, supported by web servers (like Apache & nginx) and browsers. HTTPS layers Hypertext Transfer Protocol (HTTP) on top of the SSL/TLS protocol.

Why

Why?

Contents


How to

Obtain

Buying or obtaining free SSL certificates today

  • Let’s Encrypt is now in public beta. They provide free domain-validated certificates. They do not offer EV certs or wildcard certs. Certificates are obtained using the Let’s Encrypt client which automatically manages renewals, or any of the alternative clients, including Get HTTPS for free, a simple browser-based client that looks more like a traditional CA.
  • startssl.com offers free SSL certificates for single domains. If you verify your identity, they will also allow you to register free wildcard certs.
  • namecheap.com offers single-domain SSL certificates for $7.95/year and wildcard certificates for $85/year
  • GlobalSign offers free wildcard certificates (!) for open source projects.
  • ssls.com has inexpensive SSL certificates from multiple providers. As of 2014/03/08, a PositiveSSL certificate was $4.99/yr when buying 5 years. They also provide *free* SSL certificates for 90 day periods.
  • CAcert is a community-driven non-profit that provides free wildcard certificates. Unfortunately the root certificate is not included in most operating systems or browsers by default. These certs are commonly used in the GNU community.
  • Amazon Web Services provides free SSL certificates that can be used with other Amazon services. There is no setup required other than clicking through the web interface.

Validating Your Purchase

SSL Certificate providers require some form of verification of you, your domain, and your ownership of your domain.

CSR Generation — A Certificate Signing Request must be generated at your site. For example, on a hosting provider that uses Cpanel, the "SSL/TLS Manager" has a "Certificate Signing Requests" section.

Approver Email — ssls.com asks for an "Approver Email" from a list of administration email addresses and Domain Registration email addresses. Choose one that you use, and receive the Domain Control Validation email, which contains a link and a "validation code". Click the link and enter the code to verify that you own the domain.

Certificate Email — ssls.com send the certificate to the "Administrator Email" that you specified during the purchase process. This certificate is used in the process below.

Let’s Encrypt

Alternatively you can use Let’s Encrypt. In order to obtain a certificate you need to use their client. Log into the machine hosting your website and install the client with git: 

git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt
./letsencrypt-auto --help

There are several ways we can proceed, for this example we shall simply obtain the certificates. In order to authenticate, the client will run its own server. Any server already running will conflict so we need to temporarily stop it: 

sudo systemctl stop nginx # or equivalent command
./letsencrypt-auto certonly --standalone --standalone-supported-challenges tls-sni-01

The client will start and then ask you to enter a list of domains you wish to use the certificate for. You could, for example, enter www.example.com,example.com. Once the client has finished it will create the folder /etc/letsencrypt/live/www.example.com which will contain the files cert.pem, chain.pem, fullchain.pem and privkey.pem. You can then reference these files in your server’s config.

Manage

When you're done with your purchase, you'll have one or more files for each certificate:

  • The certificate itself, e.g. snarfed.org.ssl.crt.
  • The private key you used to generate the certificate, e.g. id_rsa-2048.
  • Optional: Your CA's intermediate cert, e.g. sub.class1.server.ca.pem.
  • Optional: Your CA's root, e.g. ca.pem. Hopefully you picked a CA whose root cert is distributed with most OSes/browsers; if so, you can ignore this. (If you didn't, you should reconsider!)

All of these files are usually X.509 format except the private key, which is RSA or other private key format.

Command line openssl is your friend for inspecting and editing certificates. For example, to dump info about a cert: 

openssl x509 -text -in snarfed.org.ssl.crt

If your CA provided an intermediate cert, you'll need to provide it to your web server along with your own cert. For servers that only accept a single file, you'll need to concatenate the certs, e.g.: 

cat snarfed.org.ssl.crt sub.class1.server.ca.pem > snarfed.org.unified.ssl.crt

As another example, it seems like this command line should verify that a cert is valid: 

openssl verify -verbose -CAfile ca.pem snarfed.org.unified.ssl.crt

...but User:snarfed.org gets this error: 

error 20 at 0 depth lookup:unable to get local issuer certificate

You will get the "error 20" error above when openssl is unable to locate the root or intermediate certificates in your chain - if you are on Linux, or know where your OS stores the certificate list, you can run: 

openssl verify -verbose -CApath /etc/ssl/certs snarfed.org.unified.ssl.crt

If you have gnutls command line tools installed, you can verify self-signed certs: 

certtool -e --infile snarfed.org.unified.ssl.crt


Setup

The IETF has a document with recommendations for Secure Use of TLS and DTLS.

Mozilla has a great tool to build the SSL Configuration for various tools: Mozilla SSL Configuration Generator.

https://cipherli.st is a quick cheatsheet for Apache, nginx and Lighttpd TLS configuration.

Apache

Apache is pretty easy. Here's a good how-to post. TL;DR: Put the certificate files somewhere your Apache user can read, then set the SSLCertificate* config directives, e.g.: 

SSLCertificateKeyFile /home/ryan/.ssh/id_rsa-2048
SSLCertificateFile /home/ryan/www/snarfed.org.ssl.crt
SSLCACertificateFile /home/ryan/www/sub.class1.server.ca.pem

User:ShaneHudson.net - As well as the certificates and keys, it is also useful to have forward secrecy and HSTS. I used the following lines in httpd.conf, the articles I found them in are in the FAQs further below. This went from C to A+ on the SSL test. 

SSLProtocol all -SSLv2 -SSLv3
    SSLHonorCipherOrder on
    SSLCipherSuite "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS"
    Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"

App Engine

If you're serving on Google AppEngine's built-in appspot.com domain, you're already done! Just add secure: always (or optional) to the handler(s) in your app.yaml or other app config file, and you'll be able to access your app over https. Details here.

If you're using the Java runtime on App Engine, add this stanza to your web.xml file. 

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 
   ...> 

  <security-constraint>
    <web-resource-collection>
      <url-pattern>/*</url-pattern>
    </web-resource-collection>
    <user-data-constraint>
      <transport-guarantee>CONFIDENTIAL</transport-guarantee>
    </user-data-constraint>
  </security-constraint>

You may additionally want to send a HSTS header to further improve security. In java, the easiest way from a servlet running on AppEngine is to add this header to all responses when running on the production server. 

import com.google.appengine.api.utils.SystemProperty;

...

      if (SystemProperty.environment.value() ==
          SystemProperty.Environment.Value.Production) {
          // force ssl for six months.
          response.addHeader("Strict-Transport-Security", "max-age=15768000");
      }

If you also deliver static content, you may want to enable the HSTS header here as well. An example stanza within your appengine-web.xml file might look like this. 

<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
...
    <static-files>
    <include path="/static/**" >
      <http-header name="Strict-Transport-Security" value="max-age=15768000"/>
...



If you're on a custom domain, you can use either SNI or a VIP. Details here. You'll need to upload your SSL cert files to the Google Apps control panel for your domain, then add and configure SNI or VIP slots in App Engine.

nginx

We can setup nginx to listen on port 443 with our SSL sertificate quite easily: 

server {
    listen 443 ssl;
    server_name example.org;

     ssl_certificate /path/to/unified.crt;
     ssl_certificate_key /path/to/my-private-decrypted.key;

     //usual nginx config here like location blocks
}

For more detailed nginx config instructions see the page on nginx

Test

Production

Qualys's SSL Server Test is an easy way to test the SSL cert on your live site. See e.g. brid.gy's report card, or for comparison jonnybarnes.uk gets slightly different results.

shaaaaaaaaaaaaa.com will check if your SSL Cert using SHA-1 or SHA-2 and explains why it's becoming more important.

[2] will test your web server's security header hardness and offers reasons why.

You can use openssl s_client to debug connection issues, e.g.: 

openssl s_client -connect snarfed.org:443

If your server uses SNI, you'll need to provide the hostname too: 

openssl s_client -servername www.brid.gy -connect www.brid.gy:443

Here's an example of debugging a single SSL issue:

Brand new StartSSL certificates may give an OCSP validation error for 6-24 hours after purchase. This seems to only affect Firefox and resolves itself when the certificate propagates to the validation server[3]. Firefox users can disable the check temporarily with Edit > Preferences > Advanced > Certificates > Validation, and uncheck "Use the Online Certificate Status Protocol"

Local

When developing a website locally, it may be useful to be able to test the site via https. For example, when writing an OAuth client, some providers will not redirect to a page that does not use https.

The easiest way to do this is to temporarily redirect your site to your own localhost (just for yourself) and use your site's cert. Just add a line like this to your hosts file: 

127.0.0.1	snarfed.org

This is obviously temporary, though. For a more permanent setup, you can either generate a self-signed SSL certificate for your testing domain (localhost, etc) or you can create your own SSL certificate authority and sign the certificate with that.

To assist with this, aaronpk has created an "IndieWebCamp" root authority that can sign certificates for domains ending in ".dev".

You can add a line to your hosts file for your test domain such as 

127.0.0.1   mydomain.dev

And then you can use the IndieWebCamp certificate authority to generate an SSL cert for it.

Renew

A few things to be aware of when you need to renew your certificates.

Because all of the browsers now share lists of certificates that are invalid and/or broken as part of OCSP stapling you should renew your certificate at least two days prior to it expiring and then update your server with the certificate at least a day before. This allows the various OCSP lists to update before you touch your server - if you do not you may get some customers whose browsers have an older list and your certificate will not pass their OCSP check, which is different than it being on the revocation list.

Tricks, tips, best practices

  • to avoid mixed content alerts, replace every http:// and https:// indbound ( your domain ) link to // prefix only. This is supported in all modern browsers and will automatically fall back to the protocol you're accessing the page on.

Posts about HTTPS

IndieMark Levels

Proposed IndieMark Levels of recommended support for HTTPS on your own website, as part of a security component


Level 1 security

Level 1 - Don't do the wrong thing. (what's the minimal "not wrong thing"?). Possible reasonable behaviors:

  • Refuse the connection, because if you don't support SSL, generally you're not listening on port 443, so clients can't connect. Challenge: the user has no idea what is wrong, nor how to fix it (i.e. retry going to the site with "http:" instead).

Why?

  • Avoid a misleading user experience.

IndieWeb Examples

  • ... add yourself here with the date you verified Level 1!


Level 2 security

Level 2 - Secure admin of your site - support https for your login/admin UI/page(s) with a self-signed certificate.

  • Your admin page(s):
    1. MUST be available over https
    2. SHOULD redirect from http to https automatically, so you don't accidentally log-in in the clear over http (e.g. send your site login password in the clear)
    3. SHOULD include the secure flag (PHP details) when setting any login credential or session cookies, so such cookies aren't leaked over other (possibly non-admin) http requests (e.g. enable Firesheep style session cookie re-use attacks)

Why?

  • Security for write-access to your site! Otherwise anyone can hack your CMS and post stuff as you. (e.g. using a tool like Firesheep to sniff your login session cookies, and re-use them to gain access to your admin pages.)

How to

  1. How to make your admin page(s) available over https:
    1. install a self-signed certificate (see your webhosting provider for details)
    2. navigate explicitly (e.g. by typing) to the https:// version of your site.
  2. How to redirect your admin UI from http to https automatically:
    1. make Wordpress Admin use SSL: http://codex.wordpress.org/Administration_Over_SSL
    2. make your own other software use SSL on Apache using .htaccess (derived from that WP reference), e.g. for your admin URL example.com/my-adm/
      # HTTPS-only my-adm
      RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /(.*)\ HTTP/ [NC]
      RewriteCond %{HTTPS} !=on [NC]
      RewriteRule ^/?(my-adm/) https://example.com%{REQUEST_URI}%{QUERY_STRING} [R=301,QSA,L]
      where:
      1. example.com is your personal domain, and
      2. my-adm/ is the path to your login / admin web UI.

N.B. useful htaccess file checker: htaccess checker - let's you paste in your htaccess file and test URL flow through it using sample URLs.

  1. How to secure your cookies, e.g. in PHP:
    1. set various session params before calling session_start() :
      ini_set("session.cookie_httponly", 1);
      ini_set("session.use_only_cookies", 1);
      ini_set("session.cookie_secure", 1);
      session_start();
    2. clear your cookies in your browser, use your login flow to sign-into your website, then double check your cookies are secure, e.g. in Firefox:
      1. choose Preferences... from the Firefox menu.
      2. click Privacy tab
      3. click Show Cookies...
      4. enter your domain name into the dialog's search box
      5. select the cookie your code set, e.g. "PHPSESSID"
      6. The info below the list of cookies should say:
        Send For: Encrypted connections only
        If it doesn't, or if it says something like
        Send For: Any type of connection
        then the cookie is not secure.


Note: If you actually setup a real SSL cert for your whole domain and serve your admin interface from the same domain, you have actually achieved Level 3.

IndieWeb Examples


Level 3 security

Level 3 - Serve https optionally on all your pages - provide your front-end over both http and https with a cert from a trusted CA, but not necessarily external content, thus you might still get mixed-content warnings sometimes.

Why?

  • You can link from silo profiles to your site via https
  • You can start using (requiring!) your https URL for IndieAuth logins (e.g. into the wiki)
  • Your readers can securely access your site without a scary warning message pop-up.
  • privacy for your readers (what they are choosing to read)[4]

IndieWeb Examples

IndieWeb Examples with http to https redirects (that still need fixing of mixed content warnings) - we explicitly recommend not redirecting your http pages to https unless you've ensured you have no mixed-content warnings.

  • 2014-??-?? Indiewebcamp.com itself

Level 4 security

Level 4 - Lock icon or better when serving https - be sure there's at least a lock icon next to the https in the address bar. Serve everything (home page, permalinks, images etc.) over https when the user requests https. Eliminate mixed-content warnings (e.g. triangle with exclamation mark inside next to https in the URL bar).

Why?

  • Avoid showing readers a warning message or triangle icon in the browser address bar
  • If you optionally allow http or https access to your site, and your https access *lacks* the mixed content warning, you're at least helping your https visitors.
  • Eliminating mixed-content warnings is important because those warnings are essentially making the https ineffective. The user has no idea how much of a page, it's images, scripts, or text created from scripts has come from an embedded http connection.
  • Avoid mixed http/https content which is blocked by default on Firefox & Chrome. See: https://blog.mozilla.org/security/2013/05/16/mixed-content-blocking-in-firefox-aurora/, https://code.google.com/p/chromium/issues/detail?id=81637

IndieWeb Examples in rough order of implementation


FAQ:
How do you ensure that external content is over https? E.g. if I have an avatar for a comment from Tantek Çelik it will be over http since he uses http.

  • When you receive a webmention, download the image from the h-card and serve it from your own server.
  • Alternatively, use a separate https image proxy like https://github.com/atmos/camo (used by GitHub)
  • Unless it's a Twitter mention, in which case link to:

Level 5 security

Level 5 - Redirect everything to https - send redirects from http -> https. I.e. your pages automatically always get at least a lock icon in the browser address bar (and no warnings).

Why?

  • All your site URLs will be consistent.
  • Users will more likely get content that you intended to serve them
  • All the advantages to broader internet security of always serving https (documented in intro at top)

IndieWeb Examples in rough order of implementation

  • 2014-??-?? Ryan Barrett on https://snarfed.org/ (via HSTS header)
  • 2014-05-23 Kartik Prabhu on https://kartikprabhu.com/ (via 301 redirect)
  • David Shanske on https://david.shanske.com/ since 2014-12-25.
    • At Level 3 from 2014-08-29
    • Was at Level 4 for a bit, but did not note date.
    • All posts, resources, including external user pics.
    • Caveat: There may be some older posts with embedded images from http that still give the mixed content warning. I think I have them all
      • Dropped down to B...updated ciphers and added a custom DHE parameter. As of 2016-02-14 am back at A+.
  • ...
  • ...
  • ... add yourself here with the date you reached Level 5!

Check the browser's address bar where your URL is displayed and make sure:

  1. There's a lock icon before (in front of) the URL in the address bar
  2. There's no warning triangle icon (in front of) the URL in the address bar

Why is my site running so slowly?

  • I found that moving my https redirect into httpd instead of .htaccess, and explicitly setting it to go to www meant it would be faster and wouldn't go through multiple redirects. This SO question came in handy for getting httpd to redirect. ~ Shane Hudson

Why am I only A not A+?

Level 6 security

Level 6 - Correct ciphers, support forward secrecy, etc. per https://www.ssllabs.com/ssltest/ (all previous levels required, i.e. document method of http to https redirection)

Why?

IndieWeb Examples

Criticism

Legacy Software and SNI Support

A server has an IP address. It used to be that each server would host one website (domain) in HTTP/1. Then HTTP/1.1 introduced the Host header which allowed a server to host multiple domains. However, the connection needs to be encrypted before the Host header can be sent. So which certificate should the server send initially? When the wrong one is chosen we get issues. The solution to this problem is called Server Name Indication. SNI is supported by all modern browsers and cryptography libraries. OpenSSL is one of the most popular and has supported SNI since 2010 for example. However, we can run into issues when older software tries to interact with your site: http://indiewebcamp.com/irc/2015-12-06/line/1449416119493

General X509 Criticism

Maintenance tax and site fragility

Adding HTTPS to your site adds the extra maintenance tax of HTTPS certificate renewal (and updating).

As a result, if you fail to do this, or get it wrong, your site goes down.

Evidence:

Let’s Encrypt are trying to fix this by making updating TLS certificates an automated process via their Let’s Encrypt client.

Related

Sessions

Sessions at IndieWebCamps about https:


See Also

Retrieved from "https://indiewebcamp.com/HTTPS"