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CDN Security Features: What to Look For
- Missy Ly
- Jan 6
- 11 min read
Want to keep your WordPress site fast and secure? A Content Delivery Network (CDN) can help by speeding up your website and safeguarding it from cyber threats. But not all CDNs offer the same level of protection. Here's what you need to know:
DDoS Protection: Shields your site from floods of malicious traffic, ensuring uptime during attacks.
Web Application Firewall (WAF): Blocks common hacks like SQL injection and cross-site scripting.
SSL/TLS Encryption: Secures data with HTTPS, protecting sensitive information and boosting trust.
Bot Filtering: Stops harmful bots from scraping content or launching brute-force attacks.
WordPress-Specific Features: Includes malware scanning, cache integration, and eCommerce data protection.
Pro Tip: Properly configure your CDN with secure DNS settings, strong SSL modes, and real-time monitoring to ensure maximum protection. Even small missteps, like ignoring mixed content errors or weak DDoS setups, can leave your site exposed.
Your WordPress site deserves a CDN that prioritizes both performance and security. Keep threats at bay while delivering a fast, reliable experience to your visitors.
How to Setup Cloudflare on WordPress website for speed and security
Core CDN Security Features
When picking a CDN for your WordPress site, there are four key security features to prioritize. These features work together to protect your content and visitors, ensuring your site remains resilient against modern cyber threats.
DDoS Protection and Mitigation
Distributed Denial-of-Service (DDoS) protection is crucial for defending your WordPress site against floods of malicious traffic. Acting as a shield, the CDN filters incoming traffic and disperses attack loads across its global network. By blocking threats closer to their origin - rather than routing them to distant scrubbing centers - modern CDNs handle attacks more efficiently. This protection covers multiple layers, including network, transport, and application, while machine learning helps detect complex threats like randomized DNS floods and spoofed TCP attacks.
In 2021, there were over 9.75 million DDoS attacks recorded. Considering WordPress powers more than 43% of websites, having strong DDoS protection isn’t optional - it’s a must.
To safeguard your site, look for CDNs offering unmetered DDoS protection to avoid unexpected costs during an attack. Additionally, disable XML-RPC pingbacks in your WordPress settings, as attackers often exploit this feature. Pair this with a Web Application Firewall for added defense against application-layer threats.
Web Application Firewall (WAF)
A Web Application Firewall (WAF) inspects every request before it reaches your WordPress server, blocking dangerous attacks like SQL injection, cross-site scripting, and remote code execution. These attacks account for nearly 95% of WordPress hacks. Many CDNs offer WordPress-specific rulesets that act as virtual patches for vulnerabilities in core files, themes, and plugins. For example, during the 2023 Forminator plugin vulnerability, thousands of daily attacks were blocked before the patch was released.
WAFs use detection techniques to score traffic for malicious intent and mitigation measures like CAPTCHAs or throttling to handle suspicious requests.
To boost security, enable CMS-specific rulesets and set rate limits on sensitive areas like your login page. This can help prevent brute-force attacks. Combine these measures with SSL/TLS encryption to ensure all data remains secure during transmission.
SSL/TLS Encryption and HTTPS Support
SSL/TLS encryption delivers three essential protections: verifying your site’s identity, encrypting data, and ensuring data integrity. By managing SSL certificates at the edge, a CDN ensures secure connections between users and itself - even if your origin server uses outdated certificates.
Modern CDNs support advanced protocols like TLS 1.3, which improve both speed and security. In fact, reducing page load times by just one second can increase conversion rates by 1%.
"A CDN has the added benefit of providing security to visitors of properties hosted within its network using a CDN provided certificate. Because visitors connect to only the CDN, an older or less secure certificate in use between the origin server and the CDN will not affect the client's experience." – Cloudflare
Enable features like "Always Use HTTPS" and HTTP Strict Transport Security (HSTS) to enforce encrypted connections. For maximum security, configure "Full (Strict)" SSL mode to encrypt data both from the user to the CDN and from the CDN to your origin server. Set a minimum TLS version of 1.2 and enable TLS 1.3 for optimal performance. Additionally, enable HSTS with a six-month max-age header to prevent protocol downgrade attacks.
Bot Filtering and Traffic Control
Bot filtering helps distinguish real visitors from harmful automated traffic. This protects your site from content scraping, spam, and credential-stuffing attempts. CDNs use bot scoring and behavioral analysis to detect suspicious activity and respond with actions like challenges or outright blocks. Advanced CDNs also offer tools like IP filtering, geographic blocking, and rate limiting to manage traffic.
During bot surges or active attacks, high-security modes (often called "Under Attack Mode") can require visitors to complete a challenge before entering your site. This adds an extra layer of protection without disrupting legitimate users.
Key Bot Control Features:
Bot Score & Challenges – Identifies and blocks scrapers and malicious bots
Rate Limiting – Throttles excessive requests to protect critical areas like login pages
IP & Geo Blocking – Restricts traffic based on location or IP address
Under Attack Mode – Temporarily increases security during active threats
Set rate limits on vulnerable endpoints, such as your login page and XML-RPC, to prevent automated attacks from overwhelming your server. With these features in place, you can fine-tune your CDN to address the specific security needs of your WordPress site.
WordPress-Specific Security Features
CDNs integrated with WPWorld come equipped with features designed specifically to address WordPress vulnerabilities. These tools work together to provide a strong layer of protection for your WordPress site.
Compatibility with WordPress Caching Plugins
A good CDN should integrate smoothly with popular caching plugins like W3 Total Cache and WP Rocket. This ensures that static assets - such as images, CSS, and JavaScript - are served from the CDN instead of your origin server. It’s equally important that the CDN automatically clears its cache whenever you publish or update a post, so visitors always see the latest version of your content.
For logged-in users, the CDN must forward critical WordPress cookies (like and ) and skip caching in admin areas, including and . Edge caching can significantly cut the load time for cached WordPress HTML, often by more than 50%. If your CDN offers features like minification, it’s best to disable similar settings in your caching plugin and set long expiration dates for static assets.
In addition to caching, malware scanning plays a key role in keeping your site secure.
Malware Scanning and Removal
Automated malware scanning checks your WordPress core files, themes, and plugins for harmful code and backdoors. Unlike plugin-based scans that can slow down your server, CDN-based scanning operates at the edge, keeping your server’s performance intact [2, 25]. Look for services that combine automated scanning with WordPress-specific threat intelligence and update their detection rules daily to combat new risks.
This proactive approach is especially important for sites handling sensitive customer data, such as eCommerce platforms.
Data Protection for eCommerce Sites
eCommerce sites must use end-to-end SSL/TLS encryption to protect payment and customer data. This encryption ensures data is secure, maintains its integrity, and prevents unauthorized access. CDNs that support TLS 1.3 can also speed up connections, leading to faster checkout experiences.
"Proper encryption practices are a necessity in order to prevent attackers from accessing important data." – Cloudflare
Strengthen security further by enabling two-factor authentication for admin accounts and setting rate limits on checkout pages to stop automated attacks. Using object caching tools like Redis can also improve the speed of delivering customer and product data during busy times. To handle high-traffic periods, ensure your CDN provides robust DDoS protection across Layers 3, 4, and 7, preventing service interruptions and safeguarding customer trust.
How to Set Up a Secure CDN
Ensuring your WordPress site is both fast and secure heavily depends on properly configuring your CDN. This involves focusing on three key areas: DNS and SSL settings, cache management, and ongoing monitoring. Each step is critical to closing potential security loopholes that attackers might exploit.
DNS and SSL Configuration
Start by configuring your DNS records to "proxied" mode, which activates security features like a Web Application Firewall (WAF) and DDoS protection. For instance, in Cloudflare, this is indicated by an orange cloud icon. A gray cloud, on the other hand, means you're only routing traffic through DNS without any added security features. To fully enable your CDN, update your domain's nameservers at your registrar (e.g., Bluehost or Domain.com) to point to those provided by your CDN. Note that nameserver changes typically take 24–48 hours to propagate.
For SSL/TLS encryption, choose the Full (Strict) SSL mode and enable TLS 1.3. This setup ensures true end-to-end encryption, as it requires a valid CA-signed certificate on your origin server. Avoid the "Flexible" mode, which only encrypts traffic between the browser and the CDN, leaving the connection between the CDN and your server vulnerable. TLS 1.3 also offers the added benefit of reducing connection latency by about 60ms.
To secure sensitive areas of your WordPress site, create page rules for and , setting them to "High" security and "Bypass Cache". Additionally, if you're not using the WordPress mobile app or Jetpack, block requests to using a firewall rule. This helps prevent brute-force attacks.
Once DNS and SSL are configured, the next step is to fine-tune your cache settings.
Cache Management and Content Purging
A high cache hit ratio - the percentage of requests served directly from the CDN rather than your origin server - is crucial for both performance and security. Enabling origin shielding can further reduce server load by consolidating requests before they reach your origin, while also masking your origin IP to deter direct attacks.
Set Time-to-Live (TTL) values based on content type. For example, static files like images and CSS can have longer TTLs, while pages that are updated frequently should have shorter TTLs to ensure visitors always see the latest version. After making site-wide changes, clear caches in both your WordPress and CDN dashboards to avoid issues with outdated or mixed content. Tools like WP Rocket or W3 Total Cache can simplify this process by automatically purging CDN caches whenever you update posts or pages.
With cache settings optimized, focus on keeping an eye out for potential threats.
Monitoring and Threat Response
Real-time monitoring is essential for identifying and addressing threats before they escalate. Use your CDN's analytics dashboard to track HTTP traffic patterns and spot malicious activities, such as SQL injection attempts or remote code execution attacks. Pay attention to traffic spikes from specific regions, as they could indicate a coordinated attack.
Set up instant downtime alerts and create custom WAF rules to block or challenge traffic based on IP ranges, User Agents, or geographic locations. Regularly review activity logs to track login events and any changes made to your site configuration. Checking cache hit ratios in these logs can also confirm that your CDN is efficiently serving content from the edge.
"Visibility into web traffic analytics is a key component for continuous risk assessment." – Cloudflare
Finally, monitor TLS versions in request headers to ensure you're phasing out outdated protocols. With TLS v1.0 and TLS v1.1 now accounting for less than 0.5% of total connections, it’s safe to discontinue support for these insecure versions.
Common CDN Security Mistakes to Avoid
Even with a top-tier CDN, missteps in configuration can leave your WordPress site open to vulnerabilities. Recognizing and addressing these common issues can help you steer clear of costly downtime and security risks.
Fixing Mixed Content Errors
Mixed content occurs when a secure HTTPS page tries to load some resources over HTTP. This not only weakens the secure connection but can also prompt browser warnings that scare off visitors. Luckily, the solution is simple: enable "Automatic HTTPS Rewrites" in your CDN dashboard. This feature ensures all HTTP requests are converted to HTTPS, keeping your resources secure.
Also, double-check that your WordPress site's URL and home URL in Settings > General both start with "https://" instead of "http://". After making these changes, clear your WordPress and CDN caches. Don’t forget to address header issues to avoid conflicts with external domains.
CORS Configuration Issues
CORS (Cross-Origin Resource Sharing) errors pop up when response headers are misconfigured, blocking credentialed requests. A common mistake is setting the header to a wildcard () while using credentials like cookies or authentication tokens. Browsers will block this setup for security reasons.
To fix this, specify trusted domains in your CORS headers. If your site uses multiple subdomains, validate each origin against a strict allowlist instead of echoing back the browser's request. Be sure to include the header to prevent caching issues where one domain’s response is mistakenly served to another.
"CORS isn't just another configuration hurdle, but one of the most important browser security mechanisms ever built." – Rez Moss, Head of VM Scanning, Aikido
Keep in mind, browsers - not servers - enforce CORS rules. So, if your API works in tools like Postman but fails in a browser, your CORS headers are likely misconfigured. To strengthen your site further, consider upgrading your DDoS protection.
Weak DDoS Protection Setup
Basic DDoS protection often focuses on network-level attacks (Layers 3 and 4), leaving you exposed to more advanced application-layer threats like SQL injection or cross-site scripting. With DDoS attacks costing tens of thousands of dollars per hour, it’s essential to enhance your defenses.
Start by restricting firewall access to CDN IP ranges. Deploy a Web Application Firewall (WAF) to analyze HTTP/HTTPS traffic and block malicious requests. Implement rate-limiting rules to throttle IPs that exceed normal activity levels. Finally, activate "Under Attack Mode" in your CDN settings to filter out bot traffic. These steps will help ensure your WordPress site remains secure under all circumstances.
Conclusion
Picking the right CDN security features is all about creating a layered defense system that keeps your WordPress site both safe and running efficiently. With WordPress being so widely used, it’s a favorite target for attackers constantly looking for vulnerabilities. That’s why relying on just the basics isn’t enough - your CDN needs to offer robust protection.
As Jerome Seidita, Software Engineer and CEO of Calenzy, puts it:
"Good web security is invisible to users but critical to your business's credibility. You should treat it like insurance: you hope you never need it, but you're in serious trouble without it." – Jerome Seidita, Software Engineer & CEO, Calenzy
The reality is, security requires constant attention. Hackers attempt attacks every 39 seconds, making continuous monitoring and regular audits essential. To strengthen your defenses, ensure WordPress core files, themes, and plugins are always updated. Implement Multi-Factor Authentication (MFA) for your WordPress admin and CDN dashboard, and restrict origin firewall access to your CDN's IP ranges. These steps help create a security-first environment, stopping threats at the edge before they even reach your server.
It’s also worth noting that security and performance go hand in hand. For example, modern protocols like TLS 1.3 not only secure your data but also improve site speed by reducing latency. A properly configured CDN provides both protection and performance, ensuring your site remains fast and secure.
At WPWorld, we’ve aligned our CDN security features with these best practices, offering seamless protection and optimization for your WordPress site. With WPWorld, you can trust that your site will stay secure while delivering the speed your visitors expect.
FAQs
How does a CDN help protect WordPress sites from DDoS attacks?
A Content Delivery Network (CDN) protects WordPress sites from DDoS attacks by spreading incoming traffic across a global network of servers. This prevents the origin server from being overloaded. When a flood of malicious requests occurs, the CDN’s robust infrastructure absorbs the surge and blocks harmful connections before they can disrupt your site.
CDNs also employ advanced tools like traffic filtering, rate limiting, and CAPTCHAs to detect and stop suspicious activities. Additionally, built-in Web Application Firewalls (WAFs) provide an extra layer of security by targeting threats specific to WordPress, such as repeated login attempts or malformed requests. These measures keep your site running smoothly, securely, and without interruptions - even during large-scale attacks.
WPWorld makes this even easier by offering an integrated CDN with enterprise-level DDoS protection in its hosting plans, ensuring your WordPress site stays secure with minimal effort on your part.
Why is SSL/TLS encryption important when using a CDN?
SSL/TLS encryption plays a key role in safeguarding the connection between your website visitors and the CDN's edge servers. By encrypting data during transmission, it shields sensitive information from eavesdropping and man-in-the-middle attacks, ensuring a secure flow of communication.
Beyond that, maintaining updated SSL/TLS certificates adds an extra layer of protection. This step is crucial for defending against threats like DDoS attacks and other on-path vulnerabilities. Enabling SSL/TLS with your CDN not only enhances website security but also ensures a safer and more trustworthy browsing experience for your users.
Why is filtering bots important for securing WordPress sites?
Keeping bots at bay is a crucial part of securing your WordPress site. Harmful bots can wreak havoc by spamming your content, distorting traffic data, overloading your hosting resources, and even exposing your site to threats like DDoS attacks or data breaches.
Blocking these unwanted intruders helps protect your site's functionality, ensures your analytics remain accurate, and minimizes potential security risks. It's a smart move to keep your WordPress site running efficiently and securely.
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