1. Introduction
Let’s Encrypt is a free, automated, and open certificate authority brought to you by the non-profit Internet Security Research Group (ISRG).
In this post, i’ll show you a step by step instructions how to secure your Apache with Let’s Encrypt using the certbot tool on Ubuntu 18.04.
2. Prerequisites
In order to complete this tutorial, you will need :
- you will need to have an Ubuntu 18.04 server.
- Update your system:
sudo apt update && sudo apt upgrade
2. Install Certbot
Certbot is a fully featured and easy to use tool that can automate the tasks of obtaining and renewing Let’s Encrypt SSL certificates and configuring web servers to use them. The certbot package is included in the default Ubuntu repositories.
Update the packages list and install the certbot package:
sudo apt update && sudo apt install certbot
3. Generate Strong Dh (Diffie-Hellman) Group
Diffie–Hellman key exchange (DH) is a method of securely exchanging cryptographic keys over an unsecured communication channel. We’re going to generate a new set of 2048 bit DH parameters to strengthen the security:
sudo openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048
4. obtaining a Let’s Encrypt SSL certificate
To
obtain an SSL certificate for our domain we’re going to use the Webroot
plugin that works by creating a temporary file for the requested domain
in the ${webroot-path}/.well-known/acme-challenge
directory and the Let’s Encrypt validation server makes HTTP requests to
validate that the DNS for the requested domain resolves to the server
where certbot runs.
To make it more simple we’re going to map all HTTP requests for .well-known/acme-challenge
to a single directory, /var/lib/letsencrypt
.
The following commands will create the directory and make it writable for the Apache server.
sudo mkdir -p /var/lib/letsencrypt/.well-known
sudo chgrp www-data /var/lib/letsencrypt
sudo chmod g+s /var/lib/letsencrypt
To avoid duplicating code create the following two configurations snippets:
sudo vi /etc/apache2/conf-available/letsencrypt.conf
Alias /.well-known/acme-challenge/ "/var/lib/letsencrypt/.well-known/acme-challenge/"
<Directory "/var/lib/letsencrypt/">
AllowOverride None
Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
Require method GET POST OPTIONS
</Directory>
sudo vi /etc/apache2/conf-available/ssl-params.conf
SSLCipherSuite EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
SSLProtocol All -SSLv2 -SSLv3 -TLSv1 -TLSv1.1
SSLHonorCipherOrder On
Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains; preload"
Header always set X-Frame-Options DENY
Header always set X-Content-Type-Options nosniff
# Requires Apache >= 2.4
SSLCompression off
SSLUseStapling on
SSLStaplingCache "shmcb:logs/stapling-cache(150000)"
# Requires Apache >= 2.4.11
SSLSessionTickets Off
SSLOpenSSLConfCmd DHParameters "/etc/ssl/certs/dhparam.pem"
The snippet above is using the chippers recommended by Cipherli.st, enables OCSP Stapling, HTTP Strict Transport Security (HSTS) and enforces few security‑focused HTTP headers.
Before enabling the configuration files, make sure both mod_ssl
and mod_headers
are enabled by issuing:
sudo a2enmod ssl
sudo a2enmod headers
Next, enable the SSL configuration files by running the following commands:
sudo a2enconf letsencryptsudo a2enconf ssl-params
Enable the HTTP/2 module which will make your sites faster and more robust:
sudo a2enmod http2.
Reload the Apache configuration for changes to take effect:
sudo systemctl reload apache2
Now, we can run Certbot tool with the webroot plugin and obtain the SSL certificate files by typing:
sudo certbot certonly --agree-tos --email admin@example.com --webroot -w /var/lib/letsencrypt/ -d example.com -d www.example.com
If the SSL certificate is successfully obtained, certbot will print the following message:
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
/etc/letsencrypt/live/example.com/fullchain.pem
Your key file has been saved at:
/etc/letsencrypt/live/example.com/privkey.pem
Your cert will expire on 2018-10-28. To obtain a new or tweaked
version of this certificate in the future, simply run certbot
again. To non-interactively renew *all* of your certificates, run
"certbot renew"
- If you like Certbot, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
Now that you have the certificate files, edit your domain virtual host configuration as follows:/etc/apache2/sites-available/example.com.conf
<VirtualHost *:80>
ServerName example.com
ServerAlias www.example.com
Redirect permanent / https://example.com/
</VirtualHost>
<VirtualHost *:443>
ServerName example.com
ServerAlias www.example.com
Protocols h2 http:/1.1
<If "%{HTTP_HOST} == 'www.example.com'">
Redirect permanent / https://example.com/
</If>
DocumentRoot /var/www/example.com/public_html
ErrorLog ${APACHE_LOG_DIR}/example.com-error.log
CustomLog ${APACHE_LOG_DIR}/example.com-access.log combined
SSLEngine On
SSLCertificateFile /etc/letsencrypt/live/example.com/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/example.com/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/example.com/chain.pem
# Other Apache Configuration
</VirtualHost>
With the configuration above we are forcing HTTPS and redirecting from www to non www version. Fell free to adjusts the configuration according to your needs.
Reload the Apache service for changes to take effect:
sudo systemctl reload apache2
You can now open your website using https://
and you’ll notice a green lock icon.
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