HTTP Header Referrer-Policy: The Comprehensive Guide
HTTP Header Referrer-Policy is a crucial aspect of web security that determines how much referrer information should be included with requests. Referrer information is sent with the Referer header and can be used for analytics, logging, optimized caching, and more. However, this information can also pose a security risk, making it important to set the Referrer-Policy correctly.
Setting the Referrer-Policy HTTP header is a best practice for web developers to prevent security vulnerabilities such as Cross-Site Scripting, Clickjacking, and Information Disclosure. By implementing proper HTTP response headers, developers can protect web pages and maintain the security and privacy of source accounts while fetching resources or performing navigation. Referrer-Policy can be delivered for a request through the HTTP header or in HTML, and it is essential to understand how to set it correctly to ensure the best protection against security risks.
In this article, readers will learn all they need to know about HTTP Header Referrer-Policy. The article will cover the basics of Referrer-Policy, HTTP headers, and security headers. It will also provide best practices for web pages and explain how to set the Referrer-Policy correctly. By the end of the article, readers will have a clear understanding of Referrer-Policy and how to implement it to enhance web security.
Definition and Purpose of the Referrer-Policy HTTP Header
Definition
The Referrer-Policy HTTP header is a security feature that controls how much information is sent with the Referrer header in an HTTP request. The Referrer header contains the URL of the web page that initiated the request. The Referrer-Policy header is used to determine which information is sent in the Referrer header and which is not. The header can be set in the HTTP response from the server or in HTML. The Referrer-Policy header is a forbidden header name, which means it cannot be modified by JavaScript.
Purpose
The purpose of the Referrer-Policy HTTP header is to protect the privacy and security of users. The Referrer header can contain sensitive information, such as the user’s browsing history or login credentials. By controlling the amount of information sent in the Referrer header, the Referrer-Policy header can prevent cross-site attacks, cross-site scripting, clickjacking, and other security vulnerabilities.
The Referrer-Policy header can be set to one of the following values:
no-referrer: The Referrer header is not sent in the request.no-referrer-when-downgrade: The Referrer header is not sent if the request is from HTTPS to HTTP.same-origin: The Referrer header is sent only if the request is from the same origin.strict-origin: The Referrer header is sent only if the request is from the same origin and the request method is not aGETmethod.origin: The Referrer header is sent with the origin of the requesting document.strict-origin-when-cross-origin: The Referrer header is sent only if the request is from the same origin or if it is a cross-origin request with a safe HTTP method.origin-when-cross-origin: The Referrer header is sent with the origin of the requesting document for same-origin requests and with the full URL for cross-origin requests with a safe HTTP method.unsafe-url: The full URL of the requesting document is sent in the Referrer header for all requests.
The Referrer-Policy header can be set in the HTTP response from the server or in HTML using a meta element with a name of referrer or a referrerpolicy content attribute on an a, area, img, iframe, or link element. The noreferrer link relation can also be used on an a, area, or link element to prevent the Referrer header from being sent.
In conclusion, the Referrer-Policy HTTP header is a security feature that controls the amount of information sent in the Referrer header in an HTTP request. By setting the Referrer-Policy header, website owners can protect the privacy and security of their users and prevent security vulnerabilities.
Why Is the Referrer-Policy HTTP Header Important?
The Referrer-Policy HTTP header is an important aspect of web security and privacy. It is used to control how much information is included in the Referer header of an HTTP request. The Referer header contains information about the page or resource that initiated the request. This section will discuss the security benefits, privacy benefits, and cross-origin request protection provided by the Referrer-Policy HTTP header.
Security Benefits
The Referrer-Policy HTTP header provides several security benefits. It can help protect against data injection attacks, cross-site scripting (XSS), and clickjacking attacks. By controlling the amount of information included in the Referer header, the Referrer-Policy header can help prevent sensitive information leakage.
Privacy Benefits
The Referrer-Policy HTTP header also provides privacy benefits. It can help prevent the tracking of users’ browsing habits by third-party websites. By limiting the amount of information included in the Referer header, the Referrer-Policy header can help protect users’ privacy.
Cross-Origin Request Protection
The Referrer-Policy HTTP header can also help protect against cross-origin request attacks. Cross-origin requests are requests made from one website to another website. The Referrer-Policy header can help prevent these requests from being initiated by a third-party website.
In summary, the Referrer-Policy HTTP header is an important aspect of web security and privacy. It provides several benefits, including security, privacy, and cross-origin request protection. Web developers should use the Referrer-Policy header to help protect their users’ data and privacy.
Referrer-Policy HTTP Header Use Cases with Examples
The Referrer-Policy HTTP header controls how much referrer information should be included with requests. It is important to set the Referrer-Policy header to prevent sensitive information from being leaked to third-party websites. In this section, we will discuss the different use cases of the Referrer-Policy HTTP header and provide examples.
Web Page Configuration
The Referrer-Policy HTTP header can be set in the web page configuration to control the referrer information sent from the client-side. The following are some use cases for web page configuration:
- Cross-domain requests: If a website has multiple domains, the Referrer-Policy header can be used to prevent referrer information from being sent between domains. For example, if a user clicks on a link to a different domain, the Referrer-Policy header can be set to “no-referrer-when-downgrade” to prevent the referrer information from being sent.
- Third-party widgets: If a website uses third-party widgets, such as social media buttons, the Referrer-Policy header can be set to “strict-origin-when-cross-origin” to prevent sensitive information from being leaked to third-party websites.
- Search engines: If a website wants to prevent search engines from indexing the referrer information, the Referrer-Policy header can be set to “origin” or “strict-origin”.
HTTP Request Configuration
The Referrer-Policy HTTP header can also be set in the HTTP request configuration to control the referrer information sent from the server-side. The following are some use cases for HTTP request configuration:
- API requests: If a website has an API, the Referrer-Policy header can be set to “no-referrer” to prevent sensitive information from being leaked to third-party APIs.
- Form submissions: If a website has a form submission page, the Referrer-Policy header can be set to “same-origin” to prevent sensitive information from being leaked to third-party websites.
- Downloads: If a website allows users to download files, the Referrer-Policy header can be set to “no-referrer-when-downgrade” to prevent the referrer information from being sent to third-party websites.