# Security Best Practices for your ETH staking validator node ## :robot: Pre-requisites * Ubuntu Server or Ubuntu Desktop installed * SSH server installed * a SSH client or terminal window access In case you need to install SSH server, refer to: {% embed url="" %} In case you need a SSH client for your operating system, refer to: {% embed url="" %} ## :man\_mage:Create a non-root user with sudo privileges {% hint style="info" %} Make a habit of logging to your server using a non-root account. This will prevent the accidental deletion of files if you make a mistake. For instance, the command `rm` can wipe your entire server if run incorrectly using by a root user. {% endhint %} {% hint style="danger" %} :fire:**Tip**: Do NOT routinely use the root account. Use `su` or `sudo`, always. {% endhint %} SSH to your server with your SSH client ```bash ssh username@server.public.ip.address # example # ssh myUsername@77.22.161.10 ``` Create a new user called ethereum ``` sudo useradd -m -s /bin/bash ethereum ``` Set the password for ethereum user ``` sudo passwd ethereum ``` Add ethereum to the sudo group ``` sudo usermod -aG sudo ethereum ``` ## :closed\_lock\_with\_key: **Disable SSH password Authentication and Use SSH Keys only** {% hint style="info" %} The basic rules of hardening SSH are: * No password for SSH access (use private key) * Don't allow root to SSH (the appropriate users should SSH in, then `su` or `sudo`) * Use `sudo` for users so commands are logged * Log unauthorized login attempts (and consider software to block/ban users who try to access your server too many times, like fail2ban) * Lock down SSH to only the ip range your require (if you feel like it) {% endhint %} Create a new SSH key pair on your local machine. Run this on your local machine. You will be asked to type a file name in which to save the key. This will be your **keyname**. Your choice of [ED25519 or RSA](https://goteleport.com/blog/comparing-ssh-keys/) public key algorithm. {% tabs %} {% tab title="ED25519" %} ``` ssh-keygen -t ed25519 ``` {% endtab %} {% tab title="RSA" %} ```bash ssh-keygen -t rsa -b 4096 ``` {% endtab %} {% endtabs %} Transfer the public key to your remote node. Update **keyname.pub** appropriately. ```bash ssh-copy-id -i $HOME/.ssh/keyname.pub ethereum@server.public.ip.address ``` Login with your new ethereum user ``` ssh ethereum@server.public.ip.address ``` Disable root login and password based login. Edit the `/etc/ssh/sshd_config file` ``` sudo nano /etc/ssh/sshd_config ``` Locate **ChallengeResponseAuthentication** and update to no ``` ChallengeResponseAuthentication no ``` Locate **PasswordAuthentication** update to no ``` PasswordAuthentication no ``` Locate **PermitRootLogin** and update to prohibit-password ``` PermitRootLogin prohibit-password ``` Locate **PermitEmptyPasswords** and update to no ``` PermitEmptyPasswords no ``` **Optional**: Locate **Port** and customize it your **random** port. {% hint style="info" %} Use a **random** port # from 1024 thru 49141. [Check for possible conflicts.](https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers) {% endhint %} ```bash Port ``` Validate the syntax of your new SSH configuration. ``` sudo sshd -t ``` If no errors with the syntax validation, restart the SSH process ``` sudo systemctl restart sshd ``` Verify the login still works {% tabs %} {% tab title="Standard SSH Port 22" %} ``` ssh ethereum@server.public.ip.address ``` {% endtab %} {% tab title="Custom SSH Port" %} ```bash ssh ethereum@server.public.ip.address -p ``` {% endtab %} {% endtabs %} {% hint style="info" %} Alternatively, you might need to add the `-p ` flag if you used a custom SSH port. ```bash ssh -i ethereum@server.public.ip.address ``` {% endhint %} **Optional**: Make logging in easier by updating your local ssh config. To simplify the ssh command needed to log in to your server, consider updating your local `$HOME/.ssh/config` file: ```bash Host ethereum-server User ethereum HostName Port ``` This will allow you to log in with `ssh ethereum-server` rather than needing to pass through all ssh parameters explicitly. ## :robot: **Update your system** {% hint style="warning" %} It's critically important to keep your system up-to-date with the latest patches to prevent intruders from accessing your system. {% endhint %} ```bash sudo apt-get update -y && sudo apt dist-upgrade -y sudo apt-get autoremove sudo apt-get autoclean ``` Enable automatic updates so you don't have to manually install them. ``` sudo apt-get install unattended-upgrades sudo dpkg-reconfigure -plow unattended-upgrades ``` ## :bear: Disable root account System admins should not frequently log in as root in order to maintain server security. Instead, you can use sudo execute that require low-level privileges. ```bash # To disable the root account, simply use the -l option. sudo passwd -l root ``` ```bash # If for some valid reason you need to re-enable the account, simply use the -u option. sudo passwd -u root ``` ## :tools: Setup Two Factor Authentication for SSH \[Optional] {% hint style="info" %} SSH, the secure shell, is often used to access remote Linux systems. Because we often use it to connect with computers containing important data, it’s recommended to add another security layer. Here comes the two factor authentication (*2FA*). {% endhint %} ``` sudo apt install libpam-google-authenticator -y ``` To make SSH use the Google Authenticator PAM module, edit the `/etc/pam.d/sshd` file: ``` sudo nano /etc/pam.d/sshd ``` Add the following line: ``` auth required pam_google_authenticator.so ``` Now you need to restart the `sshd` daemon using: ``` sudo systemctl restart sshd.service ``` Modify `/etc/ssh/sshd_config` ``` sudo nano /etc/ssh/sshd_config ``` Locate **ChallengeResponseAuthentication** and update to yes ``` ChallengeResponseAuthentication yes ``` Locate **UsePAM** and update to yes ``` UsePAM yes ``` Save the file and exit. Run the **google-authenticator** command. ``` google-authenticator ``` It will ask you a series of questions, here is a recommended configuration: * Make tokens “time-base”": yes * Update the `.google_authenticator` file: yes * Disallow multiple uses: yes * Increase the original generation time limit: no * Enable rate-limiting: yes You may have noticed the giant QR code that appeared during the process, underneath are your emergency scratch codes to be used if you don’t have access to your phone: write them down on paper and keep them in a safe place. Now, open Google Authenticator on your phone and add your secret key to make two factor authentication work. {% hint style="danger" %} **Note**: If you are enabling 2FA on a remote machine that you access over SSH you need to follow **steps 2 and 3** of [this tutorial](https://www.digitalocean.com/community/tutorials/how-to-set-up-multi-factor-authentication-for-ssh-on-ubuntu-18-04) to make 2FA work. {% endhint %} ## :jigsaw: Secure Shared Memory {% hint style="info" %} One of the first things you should do is secure the shared [memory](https://www.lifewire.com/what-is-random-access-memory-ram-2618159) used on the system. If you're unaware, shared memory can be used in an attack against a running service. Because of this, secure that portion of system memory. To learn more about secure shared memory, read this [techrepublic.com article](https://www.techrepublic.com/article/how-to-enable-secure-shared-memory-on-ubuntu-server/). {% endhint %} {% hint style="warning" %} **One exceptional case** There may be a reason for you needing to have that memory space mounted in read/write mode (such as a specific server application like **DappNode** that requires such access to the shared memory or standard applications like Google Chrome). In this case, use the following line for the fstab file with instructions below. ``` none /run/shm tmpfs rw,noexec,nosuid,nodev 0 0 ``` The above line will mount the shared memory with read/write access but without permission to execute programs, change the UID of running programs, or to create block or character devices in the namespace. This a net security improvement over default settings. **Use with caution** With some trial and error, you may discover some applications(**like DappNode**) do not work with shared memory in read-only mode. For the highest security and if compatible with your applications, it is a worthwhile endeavor to implement this secure shared memory setting. Source: [techrepublic.com](https://www.techrepublic.com/article/how-to-enable-secure-shared-memory-on-ubuntu-server/) {% endhint %} Edit `/etc/fstab` ``` sudo nano /etc/fstab ``` Insert the following line to the bottom of the file and save/close. This sets shared memory into read-only mode. ``` tmpfs /run/shm tmpfs ro,noexec,nosuid 0 0 ``` Reboot the node in order for changes to take effect. ``` sudo reboot ``` ## :chains:**Install Fail2ban** {% hint style="info" %} Fail2ban is an intrusion-prevention system that monitors log files and searches for particular patterns that correspond to a failed login attempt. If a certain number of failed logins are detected from a specific IP address (within a specified amount of time), fail2ban blocks access from that IP address. {% endhint %} ``` sudo apt-get install fail2ban -y ``` Edit a config file that monitors SSH logins. ``` sudo nano /etc/fail2ban/jail.local ``` Add the following lines to the bottom of the file. {% hint style="info" %} :fire: **Whitelisting IP address tip**: The `ignoreip` parameter accepts IP addresses, IP ranges or DNS hosts that you can specify to be allowed to connect. This is where you want to specify your local machine, local IP range or local domain, separated by spaces. ```bash # Example ignoreip = 192.168.1.0/24 127.0.0.1/8 ``` {% endhint %} ```bash [sshd] enabled = true port = <22 or your random port number> filter = sshd logpath = /var/log/auth.log maxretry = 3 # whitelisted IP addresses ignoreip = ``` Save/close file. Restart fail2ban for settings to take effect. ``` sudo systemctl restart fail2ban ``` ## :bricks:**Configure your Firewall** The standard UFW firewall can be used to control network access to your node. With any new installation, ufw is disabled by default. Enable it with the following settings. * Port 22 (or your random port #) TCP for SSH connection * Ports for p2p traffic * Lighthouse uses port 9000 tcp/udp * Teku uses port 9000 tcp/udp * Prysm uses port 13000 tcp and port 12000 udp * Nimbus uses port 9000 tcp/udp * Lodestar uses port 30607 tcp and port 9000 udp * Port 30303 tcp/udp eth1 node {% tabs %} {% tab title="Lighthouse" %} ```bash # By default, deny all incoming and outgoing traffic sudo ufw default deny incoming sudo ufw default allow outgoing # Allow ssh access sudo ufw allow ssh #/tcp # Allow p2p ports sudo ufw allow 9000/tcp sudo ufw allow 9000/udp # Allow eth1 port sudo ufw allow 30303/tcp sudo ufw allow 30303/udp # Enable firewall sudo ufw enable ``` {% endtab %} {% tab title="Prysm" %} ```bash # By default, deny all incoming and outgoing traffic sudo ufw default deny incoming sudo ufw default allow outgoing # Allow ssh access sudo ufw allow ssh #/tcp # Allow p2p ports sudo ufw allow 13000/tcp sudo ufw allow 12000/udp # Allow eth1 port sudo ufw allow 30303/tcp sudo ufw allow 30303/udp # Enable firewall sudo ufw enable ``` {% endtab %} {% tab title="Teku" %} ```bash # By default, deny all incoming and outgoing traffic sudo ufw default deny incoming sudo ufw default allow outgoing # Allow ssh access sudo ufw allow ssh #/tcp # Allow p2p ports sudo ufw allow 9000/tcp sudo ufw allow 9000/udp # Allow eth1 port sudo ufw allow 30303/tcp sudo ufw allow 30303/udp # Enable firewall sudo ufw enable ``` {% endtab %} {% tab title="Nimbus" %} ```bash # By default, deny all incoming and outgoing traffic sudo ufw default deny incoming sudo ufw default allow outgoing # Allow ssh access sudo ufw allow ssh #/tcp # Allow p2p ports sudo ufw allow 9000/tcp sudo ufw allow 9000/udp # Allow eth1 port sudo ufw allow 30303/tcp sudo ufw allow 30303/udp # Enable firewall sudo ufw enable ``` {% endtab %} {% tab title="Lodestar" %} ```bash # By default, deny all incoming and outgoing traffic sudo ufw default deny incoming sudo ufw default allow outgoing # Allow ssh access sudo ufw allow ssh #/tcp # Allow p2p ports sudo ufw allow 30607/tcp sudo ufw allow 9000/udp # Allow eth1 port sudo ufw allow 30303/tcp sudo ufw allow 30303/udp # Enable firewall sudo ufw enable ``` {% endtab %} {% endtabs %} ```bash # Verify status sudo ufw status numbered ``` {% hint style="danger" %} Do not expose Grafana (port 3000) and Prometheus endpoint (port 9090) to the public internet as this invites a new attack surface! A secure solution would be to access Grafana through a ssh tunnel with Wireguard. {% endhint %} Only open the following ports on local home staking setups behind a home router firewall or other network firewall. :fire: **It is dangerous to open these ports on a VPS/cloud node.** ```bash # Allow grafana web server port sudo ufw allow 3000/tcp # Enable prometheus endpoint port sudo ufw allow 9090/tcp ``` Confirm the settings are in effect. > ```csharp > # Verify status > sudo ufw status numbered > To Action From > -- ------ ---- > [ 1] 22/tcp ALLOW IN Anywhere > # SSH > [ 2] 3000/tcp ALLOW IN Anywhere > # Grafana > [ 3] 9000/tcp ALLOW IN Anywhere > # eth2 p2p traffic > [ 4] 9090/tcp ALLOW IN Anywhere > # Prometheus > [ 5] 30303/tcp ALLOW IN Anywhere > # eth1 node > [ 6] 22/tcp (v6) ALLOW IN Anywhere (v6) > # SSH > [ 7] 3000/tcp (v6) ALLOW IN Anywhere (v6) > # Grafana > [ 8] 9000/tcp (v6) ALLOW IN Anywhere (v6) > # eth2 p2p traffic > [ 9] 9090/tcp (v6) ALLOW IN Anywhere (v6) > # Prometheus > [10] 30303/tcp (v6) ALLOW IN Anywhere (v6) > # eth1 node > ``` **\[ Optional but recommended ]** Whitelisting (or permitting connections from a specific IP) can be setup via the following command. ```bash sudo ufw allow from # Example # sudo ufw allow from 192.168.50.22 ``` {% hint style="info" %} :confetti\_ball: **Port Forwarding Tip:** You'll need to forward and open ports to your validator. Verify it's working with or [https://canyouseeme.org/](https://canyouseeme.org) . {% endhint %} ## :telephone\_receiver: Verify Listening Ports If you want to maintain a secure server, you should validate the listening network ports every once in a while. This will provide you essential information about your network. ```bash sudo ss -tulpn # Example output. Ensure the port numbers look right. # Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process # tcp LISTEN 0 128 127.0.0.1:5052 0.0.0.0:* users:(("lighthouse",pid=12160,fd=22)) # tcp LISTEN 0 128 127.0.0.1:5054 0.0.0.0:* users:(("lighthouse",pid=12160,fd=23)) # tcp LISTEN 0 1024 0.0.0.0:9000 0.0.0.0:* users:(("lighthouse",pid=12160,fd=21)) # udp UNCONN 0 0 *:30303 *:* users:(("geth",pid=22117,fd=158)) # tcp LISTEN 0 4096 *:30303 *:* users:(("geth",pid=22117,fd=156)) ``` Alternatively you can use `netstat` ```bash sudo netstat -tulpn # Example output. Ensure the port numbers look right. # Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name # tcp 0 0 127.0.0.1:5052 0.0.0.0:* LISTEN 12160/lighthouse # tcp 0 0 127.0.0.1:5054 0.0.0.0:* LISTEN 12160/lighthouse # tcp 0 0 0.0.0.0:9000 0.0.0.0:* LISTEN 12160/lighthouse # tcp6 0 0 :::30303 :::* LISTEN 22117/geth # udp6 0 0 :::30303 :::* LISTEN 22117/geth ``` ## :woman\_astronaut: **Use** system user accounts - Principle of Least Privilege \[Advanced Users / Optional] {% hint style="info" %} **Recommended for Advanced Users Only** **Principle of Least Privilege**: Each eth2 process is assigned a *system user account* and runs under the least amount of privileges required in order to function. This best practice protects against a scenario where a vulnerability or exploit discovered in a specific process might enable access other system processes. {% endhint %} ```bash # creates system user account for eth1 service sudo adduser --system --no-create-home eth1 # creates system user account for validator service sudo adduser --system --no-create-home validator # creates system user account for beacon-chain service sudo adduser --system --no-create-home beacon-chain # creates system user account for slasher sudo adduser --system --no-create-home slasher ``` {% hint style="danger" %} :fire: **Caveats For Advanced Users** If you decide to use **system user accounts**, remember to replace the **systemd unit files** with the corresponding users. ```bash # Example of beacon-chain.service unit file User = beacon-chain ``` Furthermore, ensure the correct **file ownership** is assigned to your **system user account** where applicable. ```bash # Example of prysm validator's password file sudo chown validator:validator -R $HOME/.eth2validators/validators-password.txt ``` {% endhint %} ## :sparkles: Additional validator node best practices | | | | ---------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Networking | Assign static internal IPs to both your validator node and daily laptop/PC. This is useful in conjunction with ufw and Fail2ban's whitelisting feature. Typically, this can be configured in your router's settings. Consult your router's manual for instructions. | | Power Outage | In case of power outage, you want your validator machine to restart as soon as power is available. In the BIOS settings, change the **Restore on AC / Power Loss** or **After Power Loss** setting to always on. Better yet, install an Uninterruptable Power Supply (UPS). | | Clear the bash history |

When pressing the up-arrow key, you can see prior commands which may contain sensitive data. To clear this, run the following:

shred -u \~/.bash\_history && touch \~/.bash\_history

| ## :robot: Start staking by building a validator {% hint style="success" %} Congrats on completing the guide. :sparkles: {% endhint %} ## :rocket: References {% embed url="" %} {% embed url="" %} {% embed url="" %} {% embed url="" %} {% embed url="" %} {% embed url="" %} {% embed url="" %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://nodebridge-africa.gitbook.io/nodebridge-africa/readme/gnosis-staking-guide/guide-or-security-best-practices-for-a-eth2-validator-beaconchain-node.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.