Configuring Apache to use SSL

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Parent page: Creating a web server on a cloud

Transport Layer Security (TLS) and formerly Secure Sockets Layer (SSL) are both often referred to as SSL and allow encrypted communications over computer networks. It is important to use encryption when sending any sensitive information, such as passwords, over the internet. However, even if not sending sensitive information, encrypting the data sent from the web server to the client will prevent third parties from intercepting the data and modifying it before it continues on to the client. In almost all situations, it is a good idea to use SSL certificates to encrypt data transmitted to and from a web server over the internet.

There are two main types of certificates: a certificate signed by a third party signing authority and a self-signed certificate. In most cases you will want a certificate signed by a third party since it is very easy to do using Let's Encrypt, as described below. However, there may be some cases, such as testing, where you may still want to create a self-signed certificate instead. With this method, data sent to and from your web server will be encrypted, however, there is no third party involved vouching for the validity of your web server. For this reason, visitors to your site will still get a warning about the security of your site. If you have a public-facing site, you probably do not want to use a self-signed certificate.

Once you have your certificate and the web server is configured, it is a good idea to check the security settings using ssllabs' ssltest tool which can suggest changes to your configuration to improve security.

Signed certificate

Having a certificate signed by a Certificate Authority (CA) allows visitors to ensure they are accessing the right website, which avoids man-in-the-middle-attacks. Many CAs require a yearly fee, but one which does not is Let's Encrypt CA. Certbot is a tool that automatically creates or renews an SSL certificate signed by the Let's Encrypt CA and it automatically configures your web server to use the SSL certificate. The main Certbot page tells you everything you need to know to get started quickly. For additional details on Cerbot, see the Certbot docs.

Self-signed certificate

This section describes the procedure for creating a self-signed SSL certificate as opposed to one signed by a CA, and for configuring Apache to use it to encrypt communications. Self-signed certificates should not be used for production sites, though they may be useful for small locally used sites and for testing.

The following steps assume you are using the Ubuntu operating system. If using another Linux operating system, the steps will be similar, but the details will likely be different such as commands and locations and names of configuration files.

  1. Activate the SSL module
    Once Apache has been installed (see Installing Apache), the SSL module must be enabled with
    [name@server ~]$ sudo a2enmod ssl
    [name@server ~]$ sudo service apache2 restart
  2. Create a self-signed SSL certificate
    [name@server ~]$  sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/ssl/private/server.key -out /etc/ssl/certs/server.crt

    If you are asked for a pass phrase, it likely means that you missed the -node option. Please reissue the command checking it carefully against the above. This command will ask you a series of questions. Below is a list of the questions with example responses.

     Country Name (2 letter code) [AU]:CA
     State or Province Name (full name) [Some-State]:Nova Scotia
     Locality Name (eg, city) []:Halifax
     Organization Name (eg, company) [Internet Widgits Pty Ltd]:Alliance
     Organizational Unit Name (eg, section) []:ACENET
     Common Name (e.g. server FQDN or YOUR name) []
     Email Address []:<your email>

    The most important question to answer is the "Common Name" question which should be the domain name of your server. In the case of a virtual machine on our clouds, it should look similar to the example response except that the string of Xs should be replaced with the floating IP associated with the virtual machine.

  3. Set ownership and permissions
    Set the correct ownership and permissions of the private key with
    [name@server ~]$ sudo chown root:ssl-cert /etc/ssl/private/server.key
    [name@server ~]$ sudo chmod 640 /etc/ssl/private/server.key
  4. Configure Apache to use the certificate
    Edit Apache's SSL configuration file with
    [name@server ~]$ sudo vim /etc/apache2/sites-available/default-ssl.conf

    and change the lines

    SSLCertificateFile      /etc/ssl/certs/ssl-cert-snakeoil.pem
    SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key


    SSLCertificateFile      /etc/ssl/certs/server.crt
    SSLCertificateKeyFile /etc/ssl/private/server.key
    SSLCertificateChainFile /etc/ssl/certs/server.crt
  5. Assuming that the default-ssl.conf, file is the SSL version of the non-encrypted 000-default.conf file for the site, make sure both files have the same DocumentRoot variables.
  6. Tighten security
    Force all http traffic to https, require more modern versions of SSL, and use better cipher options first by editing the file with
    [name@server ~]$ sudo vim /etc/apache2/sites-available/default-ssl.conf
    and adding
     SSLProtocol all -SSLv2 -SSLv3
     SSLHonorCipherOrder on

    at the bottom of the entry inside the <VirtualHost> tag replacing XXX-XXX-XXX-XXX with your VM's public IP (note the '-' are needed in place of '.'). Also, put a redirect directive on our virtual host by editing the default website configuration file with

    [name@server ~]$  sudo vim /etc/apache2/sites-available/000-default.conf
    and adding the line
    Redirect permanent /

    inside the <VirtualHost> tag.

  7. Enable the SSL-enabled website
    [name@server ~]$ sudo a2ensite default-ssl.conf
    [name@server ~]$ sudo service apache2 restart