How to secure Ubuntu Nginx web server?

@enrico 

Securing an Ubuntu Nginx web server involves several steps, including securing the server itself, securing Nginx, and securing the website/application running on the server. Here are some general steps you can follow:

1. Keep the server updated: Make sure that all software and packages installed on the server are updated regularly, including the operating system and any software related to the web server, such as Nginx and PHP.
2. Harden the server: Disable unused services and ports, and configure a firewall to block unauthorized access to the server. Use SSH keys instead of passwords for remote access.
3. Install SSL/TLS certificates: Use SSL/TLS certificates to secure web traffic between the server and clients. This can be done using tools like Let's Encrypt or by purchasing a certificate from a trusted certificate authority.
4. Secure Nginx: Configure Nginx to use secure protocols, disable weak ciphers, and enable HTTP Strict Transport Security (HSTS). You can also use Nginx to limit the rate of requests from individual IP addresses to prevent DDoS attacks.
5. Secure the website/application: Make sure that the website/application running on the server is secure, by following best practices for web application security, such as input validation, parameterized queries, and password hashing.
6. Monitor the server: Set up monitoring tools to detect unusual activity on the server, such as failed login attempts or high CPU usage.

These are just some of the steps you can take to secure an Ubuntu Nginx web server. It's important to regularly review and update your security measures to stay protected against new threats.