Nginx security architecture design: preventing CSRF, XSS and SQL injection attacks

With the continuous development of the Internet, Web applications are used more and more widely. They play a key role in different areas and these applications provide users with easy access but at the same time make these applications a target for hackers and data leaks. Therefore, web application security has become more important than ever. This article will introduce how to use Nginx to build secure web applications and prevent CSRF, XSS and SQL injection attacks.

1. CSRF attack

A cross-site request forgery (CSRF) attack is an attack method that exploits user authentication to penetrate web applications by exploiting the victim's ability to authenticated session in the website to perform unexpected actions. Therefore, an attacker can perform deceptive actions such as changing passwords, transferring funds, etc. without knowing the victim's actual account credentials.

To prevent CSRF attacks, it is recommended to take the following common steps:

(1) Use unpredictable security verification codes (Token) to limit the source of requests.

(2) Verify the HTTP Referer field and force the request source.

Nginx configuration example:

First create a file named "/etc/nginx/conf.d/csrf.conf" and add the following content to it:

location /csrf {

if ($request_method != 'POST') {
    return 405;
}

# Pre-defined token
set $token "abc123";

if ($http_csrf_token != $token) {
    return 403;
}

# Place the proxied resource here

}

In this example, when the client sends a POST request to "/csrf", the server verifies the token provided in the HTTP header. If the token is not equal to the token on the server, the server returns a 403 error. If the tokens are equal, the server processes the request and returns the resource.

2. XSS Attack

A cross-site scripting (XSS) attack is an attack method that exploits vulnerabilities in web applications to inject malicious scripts to attack the victim. These scripts usually inject functions into the victim's browser through HTML text input, JavaScript and CSS injection attacks, and can steal sensitive information, tamper with pages, etc.

To prevent XSS attacks, it is recommended to take the following common steps:

(1) Verify that the entered data is correct on the client side, and avoid using unsafe JavaScript functions (such as eval).

(2) Verify all trusted inputs and encode all outputs.

(3) Use CSP (Content Security Policy) headers to restrict the resource sources that accept and set page elements.

Nginx configuration example:

Add the following to your nginx configuration file:

add_header Content-Security-Policy "default-src 'self';

    script-src 'self' 'unsafe-inline' 'unsafe-eval' 
    https://apis.google.com";

This will tell the browser to only trust resources from the current site and the Google API. Additionally, it allows the use of inline scripts within script elements.

3. SQL Injection Attack

SQL injection attack refers to attacking by manipulating SQL queries in web applications to inject executable SQL code into the database. Through this method, attackers can steal sensitive information, destroy the database, and even control the entire System.

To guard against SQL injection attacks, it is recommended to take the following common steps:

(1) Never trust user-entered data, always use prepared statements or parameterized queries.

(2) Users accessing the database should be restricted from performing operations.

(3) When selecting a database management system, ensure that it is robust and can resist SQL injection attacks.

Nginx Configuration Example:

Before attempting to interact with the database via the web interface, you need to ensure that all required credentials (username, password, etc.) are secured and not exposed on the web server.

For web services, you may also need to install Nginx's SSL module and use HTTPS to protect the transmission of sensitive data. In addition, you can use Nginx's caching module and firewall to limit network attacks and malicious behaviors.

Summary:

The security of web applications is crucial to protecting data and user privacy. Using Nginx, you can easily prevent CSRF, XSS and SQL injection attacks and protect web applications from attacks. Although none of the methods are new, they are among the most effective in practical applications, and you should update and improve your web application security policies in a timely manner.

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