Strengthening Your Blockchain Node: A Comprehensive Guide

Lovali
Monday, Sep 25, 2023

Nodes operators play a crucial role in the blockchain ecosystem: the participate to the consensus of PoS networks and they have the opportunity to participate to governance votes to influence crypto projects. With this priviledge comes the responsibility of ensuring the security of the blockchain network. In this article, we’ll explore essential security best practices for securing blockchains nodes, helping you protect the network you are participating to and your assets.

To help you fortify your blockchain node’s defenses, we’ve split this comprehensive guide into two essential parts.

Part 1: How to Secure Your Node

In the first part, we delve into the critical aspects of securing your blockchain node. We’ll walk you through best practices for protecting your node from potential threats, hardening its defenses, and implementing robust access controls. By the end of this section, you’ll have a solid foundation for a resilient and secure node.

Part 2: Monitoring and Responding to Attacks

The second part of our guide focuses on proactive monitoring and effective incident response. We’ll equip you with the tools and strategies needed to detect anomalies and potential threats in real-time. Moreover, we’ll outline steps to take when an attack occurs, enabling you to minimize the impact and swiftly recover. By mastering these skills, you’ll be better prepared to safeguard your blockchain node and uphold the network’s reliability.

Let’s embark on this journey to strengthen your blockchain node’s security and resilience.

Regular Updates and Patch Management

Keeping your OS and blockchain software up to date is fundamental. Developers often release updates to address security vulnerabilities. Establish a process to monitor and apply updates promptly to minimize the risk of exploitation.

In case of Cosmos SDK project, spend some time to understand how Cosmovisor works and, in case the project did not implement it yet, try to explain the Dev team how important and useful it is for operators.

Cosmovisor automates the process of updating the Cosmos SDK and the underlying software, ensuring seamless transitions during network upgrades. This automation reduces downtime, minimizes the risk of human error, and ultimately contributes to the overall robustness and resilience of the Cosmos network. Validators can rely on Cosmovisor to streamline their upgrade procedures, enabling them to stay in sync with the latest features and security enhancements without compromising the network’s integrity. Thus, Cosmovisor stands as a critical tool in the toolkit of validators, playing a key role in the ongoing success and security of the Cosmos ecosystem.

Node security and segregation

Implement these security measures:

Node Isolation: Host validator nodes on dedicated, isolated hardware to reduce exposure to potential threats. In case of dockerized nodes, never share the same host for multiple projects.
Firewall Rules: Configure your firewall to only allow necessary network traffic to and from your validator nodes, limiting potential attack vectors.
Just-in-Time Administration: protect your host with an external firewall and open SSH ports only when needed.
SSH Security: Use SSH key-based authentication and implement MFA authentication.
Run with Non-Privileged Account: Ensure that the blockchain software runs with a non-privileged user account. Running as a non-root user minimizes the potential impact of security vulnerabilities in the blockchain software.

At Lovali we use Google Authenticator as second authentication factor. Here is how to configure it.

Install Google Authenticator on Your Mobile Device:
- On Android, you can find it on the Google Play Store.
- On iOS, you can find it on the Apple App Store.
Log in to Your Node via SSH: Use your existing SSH key or password to log in to your node. Ensure that you have sudo privileges on the node.

Install Google Authenticator on Your Node:

On Debian/Ubuntu:

sudo apt-get update
sudo apt-get install libpam-google-authenticator

On Red Hat/CentOS:
```
sudo yum install google-authenticator
```

Run the Google Authenticator Setup: Run the following command to set up Google Authenticator for your SSH login:
```
google-authenticator
```

You will be prompted with several questions. Here are typical responses:

Do you want authentication tokens to be time-based (y/n): Type y for time-based tokens.
Do you want me to update your “/home/yourusername/.google_authenticator” file? (y/n): Type y to create the configuration file.
Do you want to disallow multiple uses of the same authentication token? (y/n): Type y if you want to restrict token reuse.
By default, tokens are good for 30 seconds. Do you want to change this? (y/n): Adjust token expiration as desired.
Do you want to enable rate-limiting? (y/n): Type y to enable rate limiting.

Scan QR Code or Manual Entry: After answering the questions, the Google Authenticator setup will display a QR code. You can scan this QR code using the Google Authenticator app on your mobile device. Alternatively, you can enter the provided “Your new secret key” and “Your verification code” manually into the app.
Backup Codes: Google Authenticator will also provide a set of one-time backup codes. These are crucial for login recovery in case you lose access to your mobile device. Store these codes in a secure place.
Configure SSH to Use Google Authenticator:
- Open your SSH configuration file:
```
sudo nano /etc/pam.d/sshd
```
- Add the following line to the file:
```
auth required pam_google_authenticator.so
```
- Save and exit the file.
Restart SSH Service:
- Restart the SSH service to apply the changes:
```
sudo systemctl restart sshd
```
Test SSH Login with Google Authenticator:
- Log out of your SSH session and then log back in. You should now be prompted for your verification code from the Google Authenticator app in addition to your password or SSH key.
Store Backup Codes Securely:
- Ensure you have stored your backup codes securely. These codes are essential for emergency access if you lose your mobile device or the Google Authenticator app.

Securing Private Keys

Private keys are the core of security in crypto projects. They play a pivotal role in authorizing transactions, signing blocks, and maintaining the integrity of the network. Consequently, safeguarding your private keys is of paramount importance for the following reasons:

1. Protection Against Unauthorized Access:

Private keys are the digital equivalent of a physical key to your assets. Anyone with access to your private key can perform transactions on your behalf. Securing them prevents unauthorized access and potential theft.

2. Maintaining Network Integrity:

In a proof-of-stake (PoS) blockchain like Cosmos, validators use private keys to sign blocks and participate in consensus. If your private keys are compromised, it can lead to network disruptions and a loss of trust from other participants.

3. Asset Protection:

Private keys grant access to your crypto assets. Losing control of your private keys could result in financial losses. Secure management is essential for protecting your investments.

4. Reputation and Trust:

Validators and node operators are entrusted with maintaining the blockchain’s stability and security. A breach due to mishandled private keys can damage your reputation and erode trust within the network.

How to Secure Private Keys for Cosmos SDK Projects:

Hardware Wallets: Consider using hardware wallets for cold storage of private keys. These devices are highly secure and keep your keys offline, away from potential online threats.
Multi-Signature (Multi-Sig) Wallets: Implement multi-signature wallets that require multiple private keys to authorize transactions. This adds an extra layer of security by ensuring that no single compromised key can initiate transactions.
Key Encryption: Encrypt private keys when storing them on your local machine or in cloud storage. Use strong encryption methods and secure password management to protect the encryption keys.
Secure Backup and Recovery: Establish a secure process for backing up and recovering private keys. Store backups in physically disconnected secure locations and consider using encrypted backups.
Access Control: Limit access to private keys to only trusted individuals who require them for specific tasks. Implement strict access control policies to prevent unauthorized access.
Regular Audits and Updates: Periodically audit your key management practices and update them as needed. This includes rotating keys, updating passwords, and reviewing access permissions.
Education and Training: Ensure that your team is well-educated on the importance of private key security. Train them in best practices for handling keys and recognizing potential threats.

Remember that securing private keys is an ongoing process. As the blockchain landscape evolves, so do the threats. By diligently following these practices, you can fortify the security of your nodes and maintain the trust of your network’s participants.

What’s next

As we conclude Part 1 of our comprehensive guide on securing your blockchain node, we hope you’ve found the information and best practices presented here valuable in bolstering the security of your node. By following the guidelines outlined in this section, you’ve taken significant steps toward fortifying your node’s defenses and protecting your investments.

But our journey doesn’t end here. There’s more to explore in Part 2 of our guide, where we’ll dive into the world of proactive monitoring and effective incident response. In Part 2, we’ll provide you with the knowledge and tools needed to detect, respond to, and recover from potential attacks on your blockchain node.

Stay tuned for Part 2, where we’ll equip you with the essential skills to not only secure your node but also to monitor and respond to threats effectively. With both parts of this guide in your arsenal, you’ll be well-prepared to navigate the challenges of blockchain security and uphold the reliability of your node and the broader network.