Keep Fingers Out of Your Pi

In my previous article on setting up the Raspberry Pi as a web server, I explain how to configure Apache and search log files for "footprints" from the IP requests that have been made to your web server. Now, I would like to discuss protecting your web server from becoming a victim to a potentially malicious attack.

Keep your Pi updated!

sudo apt update
sudo apt full-upgrade

Now, you've got the latest and greatest firmware and software!

Pi Passwords

Ideally, we would disable the default pi account, at the very least, set the default password for your pi account. Another major in-security is that most users have SSH (Secure Socket sHell) and VNC (Virtual Networking Computer) enabled so that they can remote into their machines. I don't recommend allowing access outside of your network when running a publicly exposed web server.

Apache Web Server

If you are serving web content world-wide then you'll eventually want to adopt some sort of blacklist, or exclusion list, where you can keep specific IP addresses from accessing your server. However, if you want to tighten-down your security and only allow a select few access then you'll need to make some changes.

cd /etc/apache2
sudo cp apache2.conf apache2.conf.bak
sudo vi apache2.conf OR sudo nano apache2.conf

Travel down the file until you reach this section that allows everyone access to your web server from the outside:

 Options Indexes FollowSymLinks
 AllowOverride None
 Require all granted

The AllowOverride directive is set to None meaning we will not be using an .htaccess file to override these settings. The next directive, Require is set to all granted, meaning allow anyone access.

UPDATE: I have found a significant number of bot requests in my log files, snooping for those of Us using phpmyadmin, be sure to limit access:

    Require ip 127.0.0.1
    Require ip ::1
    # Local-Area Network - update with your subnet
    Require ip 192.168.1.0/24

Next, we can add a directory that we want to protect:

 Options Indexes FollowSymLinks
 AllowOverride All

The AllowOverride directive is set to All meaning we will be using an .htaccess file to override these settings. We will provide the Require directive in our .htaccess file inside the directory we specified, in this case, "/var/www/html/hydroMazing/" One last setting of importance before we save:

# AccessFileName: The name of the file to look for in each directory
# for additional configuration directives. See also the AllowOverride
# directive.
#
AccessFileName .htaccess

You could change the name of the .htaccess file here to something harder to guess. Keep the dot at the beginning because it means hidden file. Use your imagination 😉 Now you can use an .htaccess file as your whitelist, or inclusion list:

To create a .htaccess ( or whatever you've named it ) file:

cd /var/www/html/mydirectory/

sudo vi .htaccess OR sudo nano .htaccess

# Allow access to localhost
Require ip 127.0.0.1
Require ip ::1

# Allow access to specific IPs (update with your actual IP)
Require ip 192.168.1.50

# Deny all others (implied when using Require)
# Or explicitly:

Second entry is an example — change it to your IP address (you can find this by running curl ipinfo.io/ip on the device you want to allow). Save and close the file. You can add additional access as desired.

Build a Wall

Install the open-source firewall builder (GUI-based firewall configuration)

sudo apt install fwbuilder

sudo apt install ufw
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw allow from 192.168.1.0/24 to any port 22
sudo ufw enable

After the installation has completed, you will have a new option under the Menu/Internet option from your desktop for the firewall builder GUI.

Add a new firewall and name it the same as your server.

Select the "web server" template to load default rules.

Note that the default rules restrict your server from accessing the outside Internet. In order to allow access, you'll need to add a rule. The easiest way to add a rule is to copy an existing rule that is similar to your needs.

Compile and Install

We can build our firewall through this interface, but we won't be able to install it because we won't have sufficient permissions to write to the file system. Enter the following at a terminal window's command line assuming you named your server the same as your DDNS name:

sudo mkdir /etc/fw
sudo touch /etc/fw/servername.ddns.net.fw
sudo chmod 644 /etc/fw/servername.ddns.net.fw

Now, you should be able to use the firewall builder program to compile and install the firewall. You can either restart the apache web server or simply reboot.

Anything incorrect, missing, or not working? Please let me know.

sudo apt install fail2ban
sudo systemctl enable fail2ban
sudo systemctl start fail2ban