HTTP response header attack and defense in Nginx reverse proxy

With the rapid development of the Internet, more and more websites use reverse proxy technology to improve website performance and security. Among them, Nginx is a commonly used reverse proxy software, and the response header in the HTTP protocol is also one of the important targets for attackers to attack websites. This article will explore HTTP response header attacks in Nginx reverse proxy and related defense measures.

1. HTTP response header attack

HTTP response header is the information returned by the server to the client, including response status code, response message body, etc. The attacker can achieve the purpose of attack by modifying the HTTP response header. Common attacks include:

1. XSS (cross-site scripting attack)

Attackers modify the Content-Type, Content-Security-Policy and other headers in the HTTP response header Internal information, add malicious script code, so that users can execute malicious script code when browsing the website, achieving attack purposes such as controlling the user's browser and stealing user sensitive information.

2. CSRF (cross-site request forgery attack)

The attacker forges the user's identity (such as Stealing user cookies) to complete a cross-site request forgery attack.

3. Clickjacking (Clickjacking attack)

The attacker embeds the target web page as an iframe by modifying header information such as X-Frame-Options in the HTTP response header. Go to a page crafted by the attacker and trick users into clicking on the attacker's page to implement a click hijacking attack.

2. Defense against HTTP response header attacks

In order to prevent HTTP response header attacks, the following defense measures can be taken in the Nginx reverse proxy:

1. Set a whitelist

For HTTP response header parameters, you can define a whitelist, which only allows specified parameter values ​​when used, and ignores other parameter values. This can greatly improve the security of the website and effectively prevent attackers from carrying out attacks by modifying HTTP response headers.

2. Set Content Security Policy (CSP)

Content Security Policy is a standard for web application security policy that specifies where loaded resources should come from and how Executing scripts can effectively prevent XSS attacks. In the Nginx reverse proxy, you can set up CSP to limit the source of scripts executed by the browser and prohibit the use of inline scripts, thereby effectively preventing XSS attacks.

3. Add security policies in HTTP response headers

In Nginx, you can add some security policies in HTTP response headers, including Strict-Transport-Security, X- XSS-Protection, X-Content-Type-Options, etc. These security strategies can effectively resist attacks by attackers and improve the security of the website.

4. Add appropriate security restrictions

According to the actual situation of the website, you can add some appropriate security restrictions, such as restricting the referer, User-Agent and other fields in the HTTP request , restrict file types in HTTP requests, etc. This can effectively prevent attackers from attacking by modifying HTTP response headers.

In short, the HTTP response header attack in the Nginx reverse proxy is a common attack method, but by adding security restrictions, whitelists, CSP and other defense measures, the security of the website can be effectively improved to avoid HTTP Response header attack.

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