Content Security Policy Header for WooCommerce: Secure Your Online Store

If you own a WooCommerce store and wish to stay away from security risks, it’s important to understand how to implement a content security policy header. We all know WooCommerce is a popular platform with over 6 million WooCommerce stores around the world; this makes it vulnerable to attacks like cross-site scripting (XSS), data injection, and Magecart-style card skimming.

So, if you understand the content security policy header, it will prevent you from any threats on the internet and help you run your e-commerce store smoothly.

What is a Content Security Policy Header?

Let’s understand the content security policy header. It is an HTTP response header that guides a browser to load essential parts of your website. The web server is responsible for sending this header as part of the HTTP response.

The CSP header is a type of HTTP header used to protect web applications by controlling which resources a web page can load. The policy applies to each web page individually, helping to secure the entire web application. The CSP header plays an important role in blocking malicious and unauthorized code. This security add-on prevents attackers from installing or running scripts or protects customer information at the time of checkout.

CSP can be set using a meta tag, which is a useful option for static resources or when server headers cannot be modified. CSP should ideally be set on all responses to all requests, not just the main document.

Why Your WooCommerce Store Needs a Content Security Policy Header?

How to Implement Content Security Policy Header in WooCommerce

Method 1: Using a Plugin

If you have no technical idea, you can use plugins to configure your Content Security Policy header without coding.

For this we are going to utilize Iron Security Plugin which is from WPIron. If you can follow these simple steps to get started.

• First, log in to your WordPress website.
• From the WordPress Dashboard, navigate to Plugin >> Add Plugin.
• Now activate the plugin, and from the left of the dashboard click on “Iron Security.”

• After this, click on the “HTTP Security & Headers” option from the options.

• Finally, you can simply enable the “Content Security Policy Headers” by toggling them on.

Method 2: Using .htaccess (Apache Servers) and functions.php (WordPress Theme)

.htaccess (Apache Servers)

The web server is responsible for sending the Content Security Policy (CSP) header as part of the HTTP response to enforce security rules in browsers.

Here is a code that you should add in the .htaccess file. This file is inside the root directory inside WordPress:

< IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self' https://js.stripe.com https://www.googletagmanager.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https://*.gravatar.com; font-src 'self' https://fonts.googleapis.com; connect-src 'self' https://api.stripe.com; frame-ancestors 'none';"
< /IfModule>

The default-src directive in the code above sets the default policy for loading resources and is known as the default src directive. The script src directive (script-src) controls which scripts can be loaded, while other directives like object-src, frame-src, and media-src specify allowed sources for plugins, frames, and media files, respectively.

Fetch directives such as connect-src and img-src determine how the browser can load resources from different origins. Using ‘self’ in these directives enforces a same origin policy, which helps prevent unauthorized access and enhances web security by ensuring resources are only loaded from trusted sources. This approach helps the web server securely load resources and protect against threats like cross-site scripting (XSS).

functions.php (WordPress Theme)

Locate your functions.php file of your theme file and paste this:

function add_csp_header() {
    if (!is_admin()) {
        $csp = "default-src 'self'; " .
               "script-src 'self' 'nonce-" . wp_create_nonce('csp') . "' https://js.stripe.com https://www.googletagmanager.com; " .
               "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; " .
               "img-src 'self' data: https://*.gravatar.com; " .
               "font-src 'self' https://fonts.googleapis.com; " .
               "connect-src 'self' https://api.stripe.com; " .
               "frame-ancestors 'none'; " .
               "report-uri /csp-violation-report-endpoint";
        
        header("Content-Security-Policy: " . $csp);
    }
}
add_action('send_headers', 'add_csp_header', 100);

The nonce attribute is used in Content Security Policy (CSP) directives to allow specific inline scripts and inline styles to execute securely. For each HTTP response, a random value is generated and set as the nonce attribute on your script elements and style tags. This approach enables you to execute inline script and inline styles while blocking unauthorized inline code, such as inline event handlers or other unsafe inline JavaScript code.

To enhance security, always avoid unsafe inline and do not use the unsafe-eval directive, as it allows potentially dangerous JavaScript code execution. Each content security policy directive, like script-src or style-src, can be customized using the following directive syntax to control which script elements and JavaScript code are permitted to run.

How to add HTTP Security & Content Security Headers using Iron Security?

Iron Security is a free-to-use security plugin that has essential features for your website protection. If you are not familiar with coding and want to easily implement security features, you can use this plugin. This website is compatible with platforms like WooCommerce and WordPress with support for favorite WordPress themes such as Astra, Divi, and so on.

X-Content-Type-Options Prevents MIME type sniffing

It prevents browsers from sniffing MIME types, which helps stop some attacks where browsers read files differently than the server.

X-Frame-Options Prevents clickjacking attacks

It prevents other websites from putting your site in iframes, thereby protecting you from clickjacking attacks.

X-XSS-Protection Blocks reflected XSS attacks

Cross-Site Scripting (XSS) attacks can’t happen if the browser’s built-in XSS filter is turned on.

Strict-Transport-Security (HSTS)

You can make browsers use HTTPS for your site even if they enter or follow an HTTP URL.

Referrer-Policy

Sets how much information about the site that sent the user to yours is sent back to your site.

Content Security Policy Headers

Limits the resources (JavaScript, CSS, images, etc.) that the browser can load. Content security policies (CSPs) use various csp directives to control how a requested resource is loaded and what permissions it has.

These policies can apply to a requested resource similar to how the iframe sandbox attribute works, restricting the capabilities of embedded content. CSP can also control resources loaded in nested browsing contexts, such as iframes, and the ‘child-src’ directive can be used to specify which sources are allowed for nested browsing contexts loaded within the page. This protects against XSS and other injection attacks very well.

Permissions-Policy

It tells your site and embedded content which browser features and APIs (like the camera, microphone, and geolocation) can be used.

Maintaining Your Content Security Policy Header

Regular Security Audits

It’s important to review your Content Security Policy header every three months. This ensures your website keeps up with WooCommerce’s future updates and protects your website from new security threats.

Monitor Industry Updates

As a WooCommerce site owner, stay updated with the different CSP directives and updated browsers.

• W3C CSP specification updates
• Mozilla Developer Network
• WooCommerce security advisories

Performance Impact Assessment

You shouldn’t stop after implementing the security header. Actively monitor your website performance and keep an eye on your security measures.

Conclusion

In conclusion, we hope you could understand the importance of strong Content Security Policy headers. As a successful business, it becomes your responsibility to protect your customers from internet threats and data breaches. In addition to this, you should implement other practices, like adding SSL certificates, to make your website more secure.

Your customers prefer to be loyal to your business only if they feel secure about their information. Therefore, it’s crucial to give your time and money to perfectly set up the CSP header in your WooCommerce store.

Frequently Asked Questions