Implementing Content Security Policy (CSP) in WordPress

Implementing Content Security Policy (CSP) in WordPress

Protecting your WordPress website’s security in the always-changing digital environment is crucial. While strong passwords and security plugins are essential, WordPress Content Security Policy (CSP) is an additional potent weapon you should have.

This post will explore the world of CSP and walk you through setting it up on your WordPress website so that you have an additional defense against online attacks.

Throughout this post, we’ll explain the idea of Content Security Policy (CSP) and why it’s crucial for safeguarding your WordPress website.

You’ll learn how to install CSP with ease and receive insights into potential compatibility concerns without sacrificing the functionality of your site.

If maintaining the security of your WordPress website is a critical responsibility, follow along as we explore the CSP implementation landscape.

By the end, you’ll have the information and resources necessary to improve your website’s security and the assurance to act and strengthen your online presence. Let’s begin making the WordPress site safer and more secure.

What is Content Security Policy (CSP)?

Note: Content Security Policy is also called CSP Security.

Consider CSP as the club’s bouncer, who controls entry and what patrons can do once inside. On both ends, such as entry and exist, a web application’s data access and retrieval is control with specific measures, such as headers’ security.

Addressing the CSP in WordPress, it’s a security feature That lets you list reliable sites from which your website can load files, including stylesheets, pictures, scripts, and more.

CSP improves the security of your web application and reduces the potential attack area(s).

With CSP in place, a watchful guard watches for unwanted content, trying to enter through a back door.

CSP is particularly resistant to threats like Cross-Site Scripting (XSS), Clickjacking, and data/code injection assaults. Additionally, it restrains inline scripts and controls potentially dangerous dynamic code.

CSP operates in the following manner: when a visitor arrives at your website, your web server transmits instructions via CSP as an HTTP security response header to their browser.

The browser then strictly complies with these directives, refusing to load any content that does not comply with the guidelines of the Website Content Security Policy. It acts as a security gatekeeper, ensuring only appropriate stuff can pass.

Now that we have a better grasp of CSP let’s look at how to apply it step-by-step to your WordPress website to increase security and safeguard your users’ private data.

As CSP allows you to instruct the browser where to seek scripts, styles, and other resources – you effectively tell the browser to only retrieve content from these locations by designating these trustworthy sources.

This substantially reduces the danger of XSS attacks and rejects unsolicited requests from unfamiliar domains. Any code attempting to enter from dubious sources will be met with a large “no entry” sign on the door.

Importance of Content Security Policy

What makes a Content Security Policy (CSP) so crucial for maintaining the security of your website? Let me explain it to you in more detail.

Consider CSP the dependable ally in the battle against online dangers for your website. Although it’s not your first line of defense, it is your fallback strategy and is prepared to be implemented when the bad guys arrive.

CSP is like a strong shield that can drastically lessen the harm an attacker can cause, even if it may not always stop them from getting in.

Consider the following scenario: a cunning hacker introduces malware onto your website to steal confidential data or cause mayhem.

If you have a strong CSP strategy, it’s like having a superhero. The browser responds with a resounding “nope” when the hacker’s malicious code tries to execute since this policy instructs it to “Hey, only run code from these trusted sources.”

In other words, CSP thwarts an attacker before they can take advantage of your visitors’ trust in your website.

Ensuring that only the excellent thing enters and the bad stuff is thrown out is like having a virtual bouncer at the entrance.

What’s best? You may retake control of your website and clean up the malware’s mess while CSP acts like a superhero. It is comparable to having a cleanup staff on hand immediately following a calamity.

Here is a list of benefits CSP in WordPress is used for by users:

  • Helps users allow or restrict certain code execution, such as JavaScript, Clickjacking, and online skimming attacks.
  • CSP helps developers define different policy types for various users. Depending on what users’ headers show, a developer can allow or restrict specific parts of website to particular user(s).
  • CSP in WordPress can help you maintain data standards, by meeting data protection standards. This helps users gain trust while using trusted web applications, backed by proper CSP precautions.
  • CSP helps you prevent data breaches. If your site’s HTTP response leaks sensitive information, an auditor can help you fix the issue. Along with developer’s assistant, security professionals can make HTTP headers secure, thus preventing data loss.
  • CSP can also help SEO experts improve website’s rankings and relevancy. The relevant CSP headers can tell search engines, what a specific page is about.

What exactly does CSP Protect you From?

CSP functions as an all-encompassing security guard for your website’s users. It keeps an eye out for any cyber threats but is especially wary of those that arrive via malware infestations or malicious scripts used by attackers. The top three issues that CSP excels at combating are as follows:

File Inclusion Attacks

These resemble thieves trying to enter your website through an obscure backdoor. They install web shell backdoors by exploiting flaws in WordPress plugins or themes.

However, CSP is no pushover: it prevents dubious external scripts from being injected into your website, making it nearly impossible for attackers to exploit these flaws.

File Inclusion attacks are easier to exploit. In this scenario, attackers use weakness in a web application’s verification of file inclusion commands. Once found such weaknesses in a website, random files can be included and executed on a web application. For example, a PHP shell script can be executed on a victim WordPress website, enabling hackers to include, change, or edit site files.

Cross-Site Scripting (XSS)

This sneaky attack is when a hacker injects malicious code into a web page. The browser unknowingly executes the code when a user opens that website, allowing the attacker to steal personal data, take over user sessions, or spread malware. A client in this case, can see a popup That let’s him/her take an action, or do nothing while stealing data in background.

Starting with a well-known case involving WordPress site owners, let’s dive into several real-world scenarios where Content Security Policy (CSP) comes to the rescue.

Consider operating an online store with WooCommerce on a WordPress website. Now, hackers are clever and occasionally try to insert harmful code, like malware that captures credit card numbers, straight into your WooCommerce checkout process.

This cunning action aims to steal private financial information from unwary customers. But this is where CSP emerges as the story’s protagonist.

Consider code hidden within script tags or disguising itself as a safe stylesheet utilizing style tags when it comes to CSP’s “inline scripts.”

CSP is searching for these cunning ploys. The primary goal of CSP is to stop these sneaky cross-site scripting (XSS) attacks. It’s like having a diligent security guard who yells, “Uh-uh, no malicious code allowed here!”


Consider the possibility that one of your clients clicks on a strange link in a phishing email. If you click on them, a dangerous trap established by cybercriminals may open up.

CSP intervenes by limiting the websites permitted to embed your content in frames. It’s similar to creating a security fence to ensure that only reliable websites can show your content.

This aids in preventing UI redressing attacks like clickjacking, in which users interact with harmful material without your knowledge.

How Does Content Security Policy Work?

CSP employs directives similar to rules that specify where and from where the browser can fetch content.

These instructions act as the commander’s orders, ensuring the browser adheres to the strategy precisely. Here are a few CSP directives that are frequently used:


If other directives do not override it, this directive establishes the default source for loading content. It functions as a backup plan.


This directive controls the sources that can load JavaScript. It is the keeper of your script.


Have you ever wondered where your stylesheets came from? This directive specifies the sources for loading styles. Unapproved fashions are not permitted.


Images are everything. This directive specifies where the browser can fetch image resources.


Recall the clickjacking defense we used. This directive restricts which websites may use your content in frames to safeguard your users.


It regulates where form submissions can be made. Consider it to be the online forms’ traffic cop.


A further layer of protection is added by ensuring that all resources are loaded over secure HTTPS connections.

Similar to snowflakes, each website is different. It would help if you established some restrictions to protect your website against malicious content, depending on what it does and how it was constructed.

Consider the security of your website like a layered cake right now. The Content Security Policy (CSP) layer is one of those layers. It serves as an additional layer of defense, similar to the second layer of a cake.

It’s like telling CSP, “Hey, only get content from our website.” It’s like telling them, “Trust our ingredients, but don’t trust stuff from outside unless we say it’s okay.”

However, it would help if you occasionally made an exception. You might feel more confident using another website when retrieving videos or photographs.

If so, you can designate rules that apply only to those things. The equivalent would be to say, “Okay, we trust this one friend to bring the dessert, but only for dessert.”

The main lesson is that it’s often wiser to exercise caution. CSP, therefore, prevents everything from the outside by default.

This ensures that your website is secured and only allows in what is necessary, like saying, “Nobody gets in without an invitation.” Consider creating security policies to ensure your website is as secure as possible.

Configuring Content Security Policy Directives

CSP directives function as rules for your website’s security. They specify where your website can get content.

To establish these rules, you can use website addresses (URLs) with protocols, domain names, wildcards, and unique values like “self” or “none.”

Here’s the default situation: CSP always says, “Nope, you can’t run inline scripts, and you can’t use tricky things like ‘eval.'” Cunning hackers frequently employ these tricks.

However, there is a catch. Some might think I need those inline scripts and ‘eval’ for my site to function correctly. So, they modify the script-src directive in CSP by adding the words “unsafe-inline” and “unsafe-eval.”

However, be careful because doing so poses a significant security risk and can nullify the security that previous directives have established. It’s like saying, “Sure, come on in, hackers!”

Consider this CSP header configuration, for example: “Content-Security-Policy “default-src’self’; frame-ancestors’self’.

The ‘frame-ancestors’ bit prevents clever clickjacking attempts by prohibiting content framing. The ‘default-src’ element states, “Only trust stuff from our site or this specific address.”

Content Delivery Networks (CDN) and Content Security Policy

Now let’s speak about Content Delivery Networks (CDNs), like Cloudflare, which are great news for CSP because they don’t meddle with your CSP headers from the origin server, so you don’t need to set extra rules for them.

For more information on CDN, you can see if they provide affordable, relevant, and security-based features to implement CSP on a WordPress website. You can also consult developers, security professionals, or WordPress support Teams for assistance.

WordPress Content Security Policy Implementation Obstacles

To make CSP function, you must list every resource you rely on; if you forget one, it’s like being locked out of your home. So, make sure the expert, developer, or site owner is able to make changes, the way CSP is implemented properly.

Additionally, any plugin, theme, and service you use—like Facebook or Google Maps—can contribute its resources, so you must also list those. This falls under 3rd party sources That communicate with their servers. We can call such Tools 3rd party integrations, which makes a web application able to send or receive data across various channels, such as FTP and HTTP protocols. While configuring CSP, you’ve to see, manage, and control how 3rd party tools share data across client browser and server relationships.

Remember, a tight CSP policy is terrific for increasing website security, but WordPress has specific challenges. For example, improper CSP implementation can return false positive results. Such scenarios can make life hard for users who don’t know CSP well, or lack expert’s opinion on what to do.

‘unsafe-inline,’ ‘unsafe-eval,’ and ‘data:’ should not be used in your CSP policy because WordPress themes and plugins occasionally rely on them and may break when CSP rules are applied.

As a result, once CSP is installed, it acts as a security barrier around your site. Nobody likes a closed door they can’t access, so thoroughly test everything to ensure your website continues functioning as it should.

Issues that May emerge with Compatibility

Here are some potential issues you can run into when using CSP on WordPress without enabling “unsafe-inline,” “unsafe-eval,” and “data:”

Security Plugins or Tools

Since we all know how important security is, some security-related plugins or utilities experiment with ‘eval()’ as one of its safeguards.

These security tools might only function as smoothly as they should on the WordPress backend if you include ‘unsafe-eval.’

Dynamic Script Loading

Imagine you’re employing plugins, particularly for customized or dynamic features, that dynamically import external scripts.

If ‘unsafe-eval’ isn’t in your CSP mix, these scripts can receive the cold shoulder, which means problems or missing features – not fun! Some of them might use ‘eval’ for this.

Theme Features

You occasionally encounter a WordPress theme with some creative tricks up its sleeve. And wonder what? These themes sometimes employ ‘eval’ for particular tweaks or functionality.

Some theme components might not get along if your theme occurs in the “eval” club and CSP is the bouncer.

Inline Event Handlers

Modern JavaScript folks love event listeners, but you could run into trouble if you’re old-school. Little event handlers, like ‘click’ or ‘onload.’ fall under event handlers. When CSP doesn’t allow ‘unsafe-inline,’ it’s like telling these handlers they’re not on the guest list.

Plugin Incompatibility

Imagine that you have some useful WordPress plugins to improve the functioning of your website. However, some plugins rely on an eval gimmick to work their magic.

But if you don’t allow ‘unsafe-eval’ in your CSP, these plugins might not function properly or, in the worst case, break altogether, depriving you of functionality.

Data URI Usage by Plugins or Themes

Last but not least, remember that some WordPress plugins or themes enjoy data URIs for things like icons or tiny graphics. However, if your CSP policy forbids data URIs, these resources might load incorrectly, leaving your backend appearing skewed.

Inline Styles

Are you familiar with the style tags like <style> that you occasionally see directly in HTML? Without ‘unsafe-inline,’ CSP might throw them out, so consider using external stylesheets or inline styles with ‘nonce’ or ‘hash’ attributes to keep things neat.

Data URI Usage

No inline resources are available in CSP without the ‘data:’ keyword. This prevents you from using data URIs for inline items, which may limit your style.

Inline Scripts in Admin Pages

Inline scripts in the admin area are highly favored by the WordPress core and a few plugins.

If ‘unsafe-inline’ isn’t part of your CSP, these scripts might go rogue and produce surprises or problems. They employ them to handle all kinds of behind-the-scenes magic.

Installing and Configuring Your WordPress Content Security Policy

It’s easier than it seems, and you don’t need to be a tech whiz to implement a Content Security Policy (CSP) to strengthen the security of your WordPress site.

Using plugins in WordPress

There is a simple solution for those of us who need to be IT experts: WordPress plugins. These valuable tools make adding crucial HTTP response headers, including CSP, convenient without installing additional software. You can perform this task manually, especially if you need to be more tech-savvy.

The Technical Side

You may now customize HTTP response headers for your website if you’re feeling more daring and want to get your hands dirty with the technical side.

You can use the mod_headers module if you’re using Apache and the ngx_http_headers_module if you prefer Nginx.

For Nginx:

Setting up those response headers is as simple as providing your server with instructions using the ‘add_header’ directive in your website’s server block.

For Apache:

If you’re running Apache, use the “Header set” and “Header append” commands in the “.htaccess” file located in your website’s document root to work your CSP magic.

The neat thing about this file is that everything you indicate applies to every web page on your website.

As a heads-up, you can configure HTTP response headers for all websites on your server when you use Apache, locally (in your. htaccess file) and globally.

However, be cautious because your hosting company might already have configured global response headers, especially if you’re on shared hosting.

If you choose “Header set” to configure CSP, you are essentially rewriting those global rules; however, if you choose “Header append,” you are merely adding your new policy on top instead of replacing everything.

How to Install CSP on a WordPress Site

Let’s get down to business and figure out how to set up CSP on your WordPress website.

Examine Your Website

To understand your site’s structure and adjust your CSP policy appropriately, start by closely looking at your website to see what kind of material it has and where it gets its information online.

Turn on HTTPS

Ensure your WordPress site runs on HTTPS by procuring an SSL certificate and forcing HTTPS throughout it. CSP performs better over secure connections.

Deal with Mixed Content

CSP is excellent at preventing mixed content concerns when your secure HTTPS pages load non-secure HTTP content.

Establish a Backup

Ensure you have a backup plan for your website before setting up CSP so you have a backup in case something goes wrong.

Create a CSP Policy

Choose which CSP directives are appropriate for your website, and remember to add the ‘Content-Security-Policy’ header in your .htaccess or nginx.conf file. This involves identifying where scripts, styles, pictures, fonts, and other resources can come from.

Examine the Law

Test CSP on a staging environment or a single page to ensure everything functions as it should and there are no unexpected hitches before deploying it to your live website.

Watch and Edit

Once your CS policy is active, consider how your website behaves, look for CSP-related problems in browser console logs, and adjust your policy if necessary.

Press “Report Only” to Begin

The ‘Content Security Policy-Report-Only’ header reports policy breaches without enforcing them, so you can examine what would get prohibited before going full speed during the initial rollout.

Pay Attention to Reports

Setting up reporting is essential when using CSP because it enables you to detect policy violations, pinpoint problems, and ensure that your CSP policy safeguards your site without compromising it.

It takes some testing and a thorough understanding of your site’s operation to set up a CSP setup that meets your site’s security requirements.

Additionally, remember that sometimes, losing functionality can result from changes to security protocols.

If you need help with such security headers, ask your hosting company or a WordPress Support Team for assistance.

Easy Way to Configure CSP for Your WordPress Site

Let’s discuss a simpler method for implementing a Content Security Policy (CSP) on your WordPress website.

Simple SSL Pro

The excellent plugin Simple SSL Pro is like your personal CSP wizard; it contains a particular CSP generator that eliminates the difficulty configuring CSP in WordPress.

WordPress Content Security Policy

This is how it goes:

Step 1: Learning Mode

First, you activate the learning mode, which is similar to allowing the plugin to become familiar with all the resources your website uses.

Step 2: Examine and Modify

The plugin then offers some CSP rules based on what it learned, which you can review and modify to match your site’s security settings appropriately.

Step 3: Implement

When you click “Enforce,” your content security policy goes into effect and instantly makes your website more secure. Simple. It’s like having a CSP expert in your pocket, making the entire procedure a breeze.

Final Words

Here are some key points from this article: Content Security Policy (CSP) is essential because it adds a layer of security to your website, defending it against various cyber threats, including cross-site scripting (XSS) and data injection assaults.

Without careful thought, CSP implementation can lead to compatibility problems, particularly with plugins, themes, and inline scripts used on your WordPress website.

Even though CSP may appear complicated, there are simple ways to put it up, such as WordPress plugins like Really Simple SSL Pro.

Burning Question

Have you ever wondered how to protect your WordPress website from malicious attacks without compromising the site’s functionality? Content Security Policy (CSP) is highly recommended to defend against web-based threats.

This lowers the danger of attacks like XSS and Clickjacking by allowing website administrators to define trusted sources for scripts, styles, and other resources.

However, incorrect CSP configuration might cause compatibility issues, particularly with plugins and themes that rely on methods like “eval” and data URIs.

Thankfully, simple solutions like Really Simple SSL Pro make setting up CSP for WordPress users easier.

Call To Action

If you’re worried about the security of your WordPress website, consider studying CSP deployment using user-friendly tools like Really Simple SSL Pro. It’s a wise move toward securing your site while retaining its functionality.

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