17 Security Tips To Protect Your Raspberry Pi Like A Pro

By default, Raspberry Pi has poor security. If you use it at home or in a small network, it isn’t a big deal. However, if you open ports on the Internet, use it as a Wi-Fi access point, or install it on a larger network, you need to take security measures to protect your Raspberry Pi. In this article, I’ll show you everything I do with my Linux servers at work to keep them safe.

Improving the security of a Raspberry Pi is similar to any other Linux device. There are logical steps, such as using a strong password. And there are also more complex steps like detecting attacks or using encryption.

In this article, I share 17 security tips to follow to get higher security for your Raspberry Pi (and they mostly apply to all Linux systems). If you are just using your Raspberry Pi at home, try to apply the first tips at the very least. Follow all of the tips included for a more critical setup, with Internet access or on a larger network.

If you are looking to quickly progress on Raspberry Pi, you can check out my e-book here. It’s a 30-day challenge, where you learn one new thing every day until you become a Raspberry Pi expert. The first third of the book teaches you the basics, but the following chapters include projects you can try on your own.

Introduction

Should I follow all of these tips?

As mentioned at the beginning of the article, if your Raspberry Pi is at home, with a few services and no forwarded ports in your Internet box, you are already pretty safe.

The risk level of your Raspberry Pi depends on how it’s exposed to the “real” world. You won’t take the same measures for a Retropie game console at home, and for a DMZ in your network that is open on the Internet.

But the 17 tips are good to know, and easy to apply, so if you share something on the Internet, take 30 min to read the article and apply what you learn.

How I wrote this article

I selected 17 main security tips, which apply to everyone who hosts a Raspberry Pi and shares services on it. I have been a system administrator for 20 years, and these are the tips I apply to any new server installation.

They are in order of risk level. If you think you are highly exposed, follow all the steps, and you’ll be safe.

If your risk level isn’t very much, you’ll only have to follow only the first steps.

17 Tips to Secure your Raspberry Pi

1 – Keep your system updated

This may be obvious, but it’s important. With updates from the default Raspberry Pi OS repository, you not only get the latest features but mainly security fixes for your installed applications.

Try to update your Raspberry Pi regularly with:
sudo apt update
sudo apt upgrade

You can also automate this process with the unattended-upgrades package.
This procedure allows you to install security fixes automatically every day:

• Install the unattended-upgrades package:
  sudo apt install unattended-upgrades
• Open the configuration file:
  sudo nano /etc/apt/apt.conf.d/50unattended-upgrades
• Change what you want in this file.
  By default, it’ll download only security updates, but you can change this if you want to install all Debian updates or even other repositories.
  I recommend at least uncommenting this line:
  //Unattended-Upgrade::Mail "";
  And choose a local user to receive the notifications. For example:
  Unattended-Upgrade::Mail "root";
You can only use a normal email address if you have a mail server installed.
• Save and Exit (CTRL+O, CTRL+X).
• Then we need to set the periodic upgrade.
  Open this file:
  sudo nano /etc/apt/apt.conf.d/02periodic
• Paste these lines (the file should be empty if not, change the values):
  APT::Periodic::Enable “1”;
  APT::Periodic::Update-Package-Lists “1”;
  APT::Periodic::Download-Upgradeable-Packages “1”;
  APT::Periodic::Unattended-Upgrade “1”;
  APT::Periodic::AutocleanInterval “1”;
  APT::Periodic::Verbose “2”;
  This will enable an automatic update every day.
  We ask apt to make: updates, download upgrades, install upgrades, and auto-clean every day.
  The last line is the verbose level you’ll get in the /var/log/unattended-upgrades and email (1= low, 3=max).
• Save and exit (CTRL+O, CTRL+X).
• This should be ok, you can debug your configuration with this command:
  sudo unattended-upgrades -d

Don’t forget to check the log file and/or the emails received to make sure everything is working as expected.

Are you a bit lost in the Linux command line? Check this article first, for the most important commands to remember, and a free downloadable cheat sheet so you can have the commands at your fingertips.

2 – Don’t use auto-login or empty passwords

Passwords are a big part of system security.

First: make sure that all critical access asks for a password.
Don’t use auto-login and be sure to add a login step for each application you can access directly.

I won’t list all apps, but for example, if you have a web server, make sure that personal data or administration pages aren’t accessible without a password.

Make sure that nobody uses an empty password on the Raspberry Pi. If you have a few accounts, it’s easy to check all access.

If you have a lot of user accounts, these commands could help you:

• Search for empty passwords:
  sudo awk -F: '($2 == "") {print}' /etc/shadow
  This will display only accounts with an empty password.
• Lock unsafe accounts:
  passwd -l <username>

3 – Change the default password for pi

A common mistake is to leave the default password on the pi user (raspberry). Anyone who has already used a Raspberry Pi will know this password. So many people are scanning SSH ports and trying to log in with pi/raspberry.

Changing the default password should be the first thing to do on a new installation.
Doing this is easy, log in as pi and enter this command:
passwd

Try to use a sentence with over 15 characters to be safe against brute-force attacks, and to remember it easily (ex: iloveraspberrytips is a good password easy to remember). If you need some ideas, this website offers an easy-to-remember password generator (yes it’s mine, but I love that kind of password).

4 – Disable the pi user

As I said, the pi user is one of the most brute-forced logins with root. Hackers have a list of commonly used logins and mainly try these ones.

If possible, create a new user and disable the pi user to prevent these kinds of attacks:

• Create a new user:
  sudo adduser <username>
• Give him the sudo privilege if needed:
  sudo adduser <username> sudo
This will add your new user to the sudo group.
• Check that everything is working correctly (ssh access, sudo, …).
• Copy files from the pi user to the new user if needed:
  sudo cp /home/pi/Documents/* /home/<username>/Documents/ ...
• Delete the pi user:
  sudo deluser -remove-home pi
  If you prefer, you can start by locking the account (like said previously), and delete it only after a few weeks, when you’re sure everything is working fine.

Related articles:

• How to Change the Default Raspberry Pi Username
• How to Create a New User on Raspberry Pi

5 – Stop unnecessary services

On Raspberry Pi, we try a lot of projects for everything, and it could be a bad habit for security.

Let’s say you installed PHPMyAdmin 3 months ago to try something, but you’re not using it anymore. This could create a breach for an attacker that will allow them to enter your system.

Try to stop or uninstall unneeded services and apps:

• List running services:
  sudo service --status-all
• To stop a service use:
  sudo service <service-name> stop
If it starts automatically on boot, try:
  sudo update-rc.d <service-name> remove
• Or to uninstall it, it should be something like:
  sudo apt remove <service-name>

6 – Make sudo require a password

As you should know, sudo doesn’t always ask for a password. Most of the time you don’t need to type your password again. It’s cool for productivity, but for security reasons, it’s not a good idea.

If someone succeeds to get terminal access to your Raspberry Pi main user, super-user privileges will be accessible without a password.

I recommend you ask for a password when you use sudo:

• Edit this file:
  sudo nano /etc/sudoers.d/010_pi-nopasswd
• Find this line:
  pi ALL=(ALL) NOPASSWD: ALL
Or any other users if you followed the previous steps.
• Replace it with:
  pi ALL=(ALL) PASSWD: ALL
• Do the same for each user with sudo access.
• Save and exit (CTRL+O, CTRL+X).

7 – SSH: Prevent root login

As I said previously, root and pi users are often the main targets for brute-force attacks. It’s especially true when SSH is enabled.

So, you need to make sure that root doesn’t have direct SSH access. If you need root, log in with your normal user (not pi) and then use sudo to get super-user privileges (as explained in this article).

By default, root access is disabled.
You can check this:

• Open the SSH server configuration file:
  sudo nano /etc/ssh/sshd_config
• Find this line:
  #PermitRootLogin prohibit-password
• If you have something else, comment on this line (by adding # at the beginning).
• Save and exit (CTRL+O, CTRL+X).
• Restart the SSH server if you changed anything in the configuration file:
  sudo service ssh restart

No idea what SSH is? Start by reading my complete guide about it.

8 – SSH: Change the default port

The SSH default port is 22.

So basically, attackers will create bots to make login attempts on this port.
To prevent this, you can change the default port and set another one:

• Edit the SSH server configuration file:
  sudo nano /etc/ssh/sshd_config
• Find this line:
  #Port 22
• Replace the port with the one you want to use, and make sure to uncomment the line:
  Port 1111
Avoid port conflicts by using a free one, full list here:
  List of known ports on Wikipedia.
• Save and exit (CTRL+O, CTRL+X).
• Restart your server:
  sudo service ssh restart

Don’t forget to adjust the firewall rules if you have one.

Make a new connection test before closing the current one, as it could help you if you made a mistake.
You need to update the used port in your connection settings, with Putty it’s just after the IP address:

9 – SSH: Use SSH keys instead of passwords

With the previous steps, we already block most of the script kiddies with broad attacks to any responding IP address.

We are now moving to things that could protect you even if you are facing a strong hacker who is especially interested in accessing your system (and not any other system).

Using a strong password will slow the attack, but it’s always possible to find it, even if it takes weeks to get the correct password. What you can do to block this, is to use SSH keys instead of passwords for your SSH connections. An attacker can guess a 15-character password, but not an SSH key.

The main idea is to generate a key on your computer, and then add it to the Raspberry Pi to allow a connection from your computer (with or without a password). I give you the step-by-step procedure at the end of this article.

Once this is working, you can only disable SSH connections with a password.
Change this line in the SSH configuration file we saw before:
PasswordAuthentication no

10 – Install Fail2ban

Fail2ban is a tool that detects brute-force attacks and blocks them.

In the previous steps, I said that an attacker could try to find your password for months, and maybe they can succeed. The main purpose of Fail2ban is to avoid this.

Fail2ban will block attackers’ IP addresses if they fail to log in more than X times. You can configure the number of tries before a ban, and the ban duration.

Follow these steps to install Fail2ban on your Raspberry Pi:

• Install the package:
  sudo apt install fail2ban
• By default, fail2ban will ban the attacker 10 min after 5 failures.
  I think it’s ok to start, but if you want to change this, all the configuration is in the /etc/fail2ban folder.
  Mainly in /etc/fail2ban/jail.conf:
  sudo nano /etc/fail2ban/jail.conf
• Restart the service if you change anything:
  sudo service fail2ban restart

This should really slow down your attacker. 5 attempts every 10 minutes is 720 tries a day. If your password is something more difficult than “password” or “123456789” it should take a long time for the hacker to find it.

Here is a link to my tutorial on how to use Fail2ban on your Raspberry Pi. Feel free to check it if you need more details or want to go deeper with the configuration of this useful service.

11 – Install a firewall

If you don’t know, a firewall allows you to block all ports except the ones you need and filter access by IP. For example, you can block everything, and just allow SSH access from your computer IP address.

As explained in this in-depth article, an antivirus is not mandatory on Raspberry Pi, and Linux in general, but a firewall is a good practice if you host some critical services on it.

I’m used to installing iptables for my firewall rules, but maybe for a beginner, it’s not the easiest route to take. So, I’ll explain to you how to install ufw (Uncomplicated FireWall), which is more straightforward, and then allow only what you need.

It’s a basic configuration with HTTP access for anyone, and SSH only for you, but you need to adapt this to what you want to do.

• Install the firewall package:
  sudo apt install ufw
• Allow Apache access for anyone:
  sudo ufw allow 80
sudo ufw allow 443
• Allow SSH access for your IP address only (not mandatory, just to give you another example):
  sudo ufw allow from 192.168.1.100 port 22
  Don’t forget to replace values with your own settings.
  On a local network, you can get your IP address with ipconfig (Windows) or ifconfig (Linux/Mac).
  If you change the SSH port in the previous step (by 1111 or anything else), replace it here.
• Enable the firewall:
  sudo ufw enable
Be careful, this will enable the firewall now, and also on boot.
  If you lose access to your device, you won’t be able to fix this, even after a reboot.
  You’ll need to change the configuration directly on the Raspberry Pi (physically).
• Check that everything is fine.

To display your current rules once ufw is enabled, use this command:
sudo ufw status verbose

For more complex configurations, check the man page.
My other tutorial about building a wireless router with firewall features can also help you.

12 – Backup your system

One of the worst consequences of an attack is to lose data.
If you back up your files correctly and regularly, you’ll be safe even if the hacker destroys your SD card.

I already wrote an article on how to back up and restore your Raspberry Pi, so I won’t repeat it here.

But the second part is critical, make sure that you can read your backup and that all of your important files are inside; otherwise, it’s useless. Testing your backup files regularly is a good practice.

13 – Crypt your connections

This is a vast topic, and I won’t give many details about this, but I’ll give you an example.

With basic protocols, data flows in clear on the network. That’s to say, if you type your password, a hacker could get it while listening to the network. Luckily, there are often other protocols that work safer by encrypting all the data.

The first thing is to stop using unsafe protocols (FTP, Telnet or HTTP for example). And then try to replace them with safer ones (SFTP, SSH, HTTPS).

The procedure depends on which protocols you are using with your Raspberry Pi. Let’s take the HTTP example.

HTTP is cool if you only use it for static content, you never type a password, and don’t have sensitive data on your server. But take the time to switch your application to use the HTTPS protocol anyway, it’ll be safer.

It’s pretty simple to do, you just need a certificate and change a few lines in the Apache or Nginx configuration. You’ll find a lot of helpful tutorials on the Internet.

And most of the time it’s easy. You can directly switch from FTP to SFTP as your Raspberry Pi already has SSH enabled. The same thing with Telnet users, why do you need Telnet while SSH is available?

Then look for all the protocols you are using (especially with sensitive data) and what you can do to improve the overall security of your system.

14 – Use a VPN

A more radical option is to access your Raspberry Pi through a VPN. VPN stands for Virtual Private Network and allows you to access remotely all services on your Raspberry Pi as if you were in the local network.

All flows between you and the Raspberry Pi will be encrypted by a strong protocol.

This is a good option to prevent opening many ports on the Internet without security.
I have an article on how to use a Raspberry Pi as an OpenVPN server, and you can easily find more help on the Internet. Recently, I switch to WireGuard, but it’s the same idea (you can find more about WireGuard here).

You can also install NordVPN or any other provider (my top VPN provider for Raspberry Pi here) if you want to use a secured tunnel to access the Internet from your Raspberry Pi.

15 – Protect physical access

The last protection is obvious but often ignored when we talk about security.
You can configure any security protocols, firewall, and VPN from all the steps before.
If your Raspberry Pi is physically accessible by anyone, it’s useless.

Make sure that the Raspberry Pi can’t be stolen easily (or the SD card), and that nobody could come and plug in a keyboard and screen and be logged in automatically. The steps to implement to protect against that kind of attack will depend on your system.

Maybe you’ll need an auto logoff after X minutes, a password in the grub boot menu, or encrypt the data on the SD card.

Think about it, what could be the worst thing that could happen if someone gets access physically to your Raspberry Pi? Then find solutions to prevent this from happening.

16 – Check your logs regularly

The last two items from this list are not really protections, but more of a commitment to follow. Most of the time, attacks are visible in the log files. So, try to read them regularly to detect any suspicious activity.

All logs are in the /var/log folder, but the main log files to check are:

• /var/log/syslog: main log file for all services.
• /var/log/message: whole systems log file.
• /var/log/auth.log: all authentication attempts are logged here.
  
• /var/log/mail.log: if you have a mail server, you’ll find a trace of recent emails sent here.
• Any critical applications log file, for example,/var/log/apache2/error.log or /var/log/mysql/error.log

Some solutions are available to simplify this work. For example, you can configure syslog to send logs to a master server, with an interface to read them, filter, etc.

You can also use logwatch to get daily reports about the system’s operation.

17 – Read the news

To keep a good security level in your projects, try to stay constantly updated.

I see new vulnerabilities in a lot of major software packages every day, and it could take weeks or more to have the fix available in the Raspberry Pi OS repository.

If you read security news regularly, you can act faster to stay protected.
Here are some good websites to follow:

• CVE Details
• Exploit DB
• NVD Feeds

You could also use a vulnerability scanner like Nessus to find only the vulnerabilities that apply to your system. But if your project requires a high level of security, you probably should not stay on Raspberry Pi.

Conclusion

That’s it, you now know the main security steps to protect your Raspberry Pi.

I know these are only the first steps, and that there are other important ones too, but we are talking about Raspberry Pi, not high-availability servers with tons of confidential data.

I think you will have good protection if you implement the 17 ideas from this article.

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