How CDNs Protect Your Website Against DDoS Attacks
How CDNs Protect Your Website Against DDoS Attacks

Security issues in the CDN such as CloudBleed Research shows that overlay networks must make compromises between security and performance. A Content Delivery Network is like a ball bearing for the Internet. The Internet’s gears would grind to a halt without edge caches that speed up the loading times of static content and images.

CDNs are a type or overlay network that brings website content closer to users to improve performance. CDN services include edge caching and SSL offloading. Edge routing is another common service offered by Internet overlay network. Cloudflare and Teridion are three of the providers of overlay networks.

Internet overlay networks enable web site providers leverage third-party infrastructure to increase performance and security. A web site provider does not need to build regional data centers. Instead, they can “rent” the infrastructure of an overlay network at a fraction.

This document discusses security concerns associated with overlay networks and CDNs. It also offers alternatives to reduce vulnerabilities and improve performance.

CDN Security and Overlay Networks

When assessing security concerns for overlay networks, there are three important architectural issues web and mobile app providers must consider:

  1. Stateful Overlay Networks vs. Stateless: It is important to know the type of edge service that an overlay network performs. Caching, routing and SSL offload are just a few examples. Security risks are increased by storing sensitive content on multiple edge nodes.
  2. SSL key required vs Keyless Overlay Networks Requiring SSL keys may provide better performance. New security vulnerabilities are created by the cost. This is especially true if content has been cached in edge nodes.
  3. Shared Vs Shared None Overlay Networks. Shared infrastructure can make other people’s problems your problem. This risk can be reduced by isolating yourself.

Stateful vs Stateless Overlay Networks

CDNs store content in many locations. Some overlay networks, on the other hand, are “stateless”, meaning that no sensitive information is stored at the edge nodes. It is very risk-free to cache static content and publicly available content in a CDN. CDNs can safely store public images, videos, and fonts.

However, a public CDN might not be the best solution if security is a concern. hosting JavaScript library in third-party CDNs can pose a risk. Restricting the number data centers for sensitive content is a good security measure.

These security concerns can be addressed by two types of stateless network overlays:

  1. SSL Offload: an Edge Node can perform the SSL handshake between the end user and the origin server. This will greatly reduce the cost of maintaining an SSL connection. It is expensive because the origin site must share its SSL keys.
  2. Edge routing An edge node is able to handle TCP termination and optimize routing to the origin server. This can increase performance without the need for SSL certificates.

SSL Key Required vs Keyless Overlay Networks

An overlay network can perform an SSL Handshake with end users via an edge node. This requires an SSL certificate issued by the origin web site. While traffic between the edge node and the end user is encrypted, cache content is not. These caches are therefore potential targets for hackers.

Overlay networks can speed up traffic without the need for SSL certificates, which reduces security risks for mobile and web app providers. CloudFlare leads the charge in promoting keyless SSL, a safer network overlay architecture.

CDN Security and “Shared All” Overlay Networks

Overlay network vendors often make large investments in security infrastructure. Their success and size pose a threat to CDN security and encourages hackers to attack. CDN Points of Presence, or POPs, increase the vulnerability of potential hackers. This increases the risk for web sites when they share SSL certificate with an overlay network provider.

A CDN serves to reduce network congestion by serving static content. The security threat is that anyone with root-like rights on a CDN server has the ability to access and replace content. CDN customers must trust that every CDN POP is secure.

Cloud security is also more difficult when multiple websites share the same network infrastructure. Cloudflare, for example, has a large shared infrastructure. Only about 3,000 CloudFlare web sites had malformed HTML tags . Even so, the bug that resulted leaked private data from more 7,000,000 web sites .

Another approach is to have overlay networks operate separate, isolated virtual networks per customer. Sometimes, segregation may be per URL. This “shared-nothing” approach ensures that no other virtual networks are affected even if one network is compromised. CloudBleed is far less likely to be discovered by customers because it isolates them from each other.

For more secure overlay networks

CDNs will continue to be popular for caching static files but CDN security is an issue with dynamic or more sensitive content. Below is a table that summarizes the different overlay networks for managing highly secure content.

Teridion is an example of an overlay network that relies on edge routing. Teridion’s solution is designed to accelerate both static and dynamic content across the internet without compromising security. To retain customers in the SaaS world, it is essential to accelerate dynamic content. Below is a chart that shows the components of the Teridion solution.

Teridion’s Architecture

Globally, thousands of Teridion sensors have been deployed in top public cloud providers. These sensors collect real-time Internet performance data and reachability data to feed Teridion’s multi-cloud orchestrator. These insights are used by the orchestrator to optimize and create a dynamically generated per customer Internet overlay network. This is called a Virtual Backbone Network. Virtual routers can be automatically created wherever it is needed to provide the most efficient route between the SaaS app and the user. Teridion’s innovation lies in the ability of the orchestrator, which allows them to provision, modify, and move routers automatically, before there is any congestion or increase in demand. This ensures the best performance between the user and the SaaS application.

Improve Web Security by Using a Content Delivery Network

No matter what industry they work in, every business should be prepared. According to our latest research, enterprises in the gambling industry are more likely to have been attacked in the past quarter than any other industry. This is 2.7x more than the number of attacks in the same time period last year.

DDoS attacks can affect any business with an online presence, even though it is a high-risk sector like gambling. These attacks can not only cause financial damage to a company, but also create distrust and damage in the company’s reputation. This is an example of what happens in the e-commerce industry. Website connectivity problems at busy times of year can impact user experience. Users can choose to visit other websites that offer better performance.

CDN Servers are an Unexpected Source of DDoS Protection

Although it may not seem obvious, IT departments might already have the platforms and tools they need to combat DDoS attacks. Companies can keep their websites safe with a Content Delivery Network (CDN), which is often associated with web performance improvement.

Many CDN providers now offer DDoS protection. CDNs are designed to analyze and absorb unusual traffic spikes. These can be either the good types like those that are found in marketing promotions. If malicious IP addresses are identified on a deny/blacklist, they can be sent into an black hole that is specific scrubbing nosdes and protect the website against a DDoS attack.

Not all CDNs are equipped to defend against DDoS attacks. While some CDNs claim to provide DDoS protection they actually rely on their infrastructure for scaling and increasing the capacity of servers with PoPs (points of presence) around the globe. To absorb attacks, this CDN uses their sheer size and not real-time intelligence.

This will be helpful for low-level DDoS attacks but it won’t suffice for most others.

CDNs may not be created equally

A CDN, which combines security and the performance a cloud-based infrastructure, can be the first port-of-call to keep a website and web applications safe from hackers and hacker attacks.

What does a CDN do to protect your DNS environment from DDoS attacks?

  • CDNs with DDoS tools and expertise can handle sudden traffic increases, provide fast loading times even during peak hours, and protect web pages and web applications against a range of attacks. This technology may include PoPs that are specifically designed to absorb DDoS traffic and inspection and cleansing traffic. It also includes proactive monitoring tools for possible attacks.
  • Did you know that the best CDN will also provide a Web Application Firewall (WAF). This will protect both websites and online apps against a specific type of DDoS attack.Layer 3 is the most serious type of DDoS attack. It affects the network. Layer 4 impacts transport and data delivery. Layer 7 impacts the application, and ultimately the end user. Only a WAF is capable of protecting against layer 7 DDoS attacks. DDoS attacks may also be used to distract from SQL injections, which can lead to hacking attempts. A WAF will protect you against these distractions.

How to Increase Content Delivery Network Security?

  1. Select a CDN provider that you can trust. As we have explained in this guide, not every content delivery network offers the same level security. Be prepared to ask questions about caching when researching CDN solutions for your business, especially regarding the location of their PoPs as well as the caching rate they allow.
  2. Check that your CDN is compatible to your SSL Certificate. Having a CDN does not mean you should neglect your website’s security by letting your SSL certificate expire. HTTPs allows a web browser to securely connect with the server.However, vulnerabilities may still occur. Your SSL certificate must be compatible with your CDN. This adds an additional layer of security optimization, starting at the origin server and continuing to your CDN servers.
  3. Take into consideration other aspects. Although this guide focuses on security, it is important to consider other factors when selecting a CDN provider. Even if your CDN is the best, users will experience a poor web experience if they start to notice high latency or slower content delivery.

The best content delivery network can help minimize or prevent damage from a DDoS attack.

A CDN that has DDoS expertise can provide a business with years of experience and the right technology to monitor its website, respond quickly to an attack and mitigate it.

Best Practices in Content Delivery Network Security

The internet is not instantaneous, despite what your super-fast Wi-Fi connection might suggest. It takes time for text, images, and videos to travel from your site’s origin to the destination of the visitor. It takes longer for content to reach its destination, the further they are apart.

This process can be accelerated by content delivery networks. Imagine that your company is located in Boston, and that someone visits your website via San Francisco. The website loading time would be very long if the content had to travel across the entire country. CDNs make this easier by storing the content on servers that are located all over the country in “points of existence”.

The “edge server” is the server closest to the user, in this case, San Francisco. It stores the most recent content updates such as blog posts and photos. The content is able to load faster because it is closer to the user than its source.

Because CDNs preserve user experience no matter where they are located, they have become a standard tool for any website owner. Even during high traffic spikes, visitors don’t need to deal with slow load times. Website owners do not have to worry about heavy traffic overloading their server of origin. Instead, the traffic is distributed across multiple CDNs.

CDN Security Concerns

However, there are risks associated with digital tools. CDNs are not able to block malicious bots from infecting websites, unlike firewalls. CDN servers that contain cached information could be hijacked and used in many ways.

Hackers could gain access to the cached information stored on CDNs that many businesses use. This would make each business’s customer information vulnerable. Cybercriminals can steal passwords, email addresses and other sensitive information via the CDN.

Another security concern for CDNs is distributed denial-of service attacks. An simulation test found that 16 CDNs were susceptible to an exploit that allowed servers to execute the same command repeatedly. They eventually became overwhelmed, and the content was taken offline.

How do you ensure CDN Security?

CDNs have security risks but they are essential for website owners who want to attract visitors from far away and provide seamless user experiences. Websites shouldn’t be vulnerable. You can take steps to make sure your CDN doesn’t compromise your website’s security.

1. Evaluate the CDN Carefully

There are many CDN providers available, some better than others. Before you commit, make sure to thoroughly research all options and ask difficult questions. To ensure that the server is secure, you need to know how often data is stored and what penetration testing has been performed. It is also important to consider what happens if the server crashes. Do you have failover security measures? Many CDN security concerns can be eliminated by choosing the right provider.

2. Use a Web Application Firewall

CDNs can be vulnerable by themselves, so you should use a Web Application Firewall along with them. It is worth considering a WAF with CDN capabilities already built in to its infrastructure. A firewall serves as a firewall between your content, and the wider internet. While the firewall prevents traffic from being sent to red flags, it allows for good website traffic. Once CDN servers are secured, the benefits of CDN servers increases significantly.

3. Get SSL Certificates Compatible

An SSL certificate is required for websites that collect information or process credit card payments. To ensure that data submitted to your website remains encrypted while it travels through the CDN, a CDN must be compatible. This completes the encryption from the CDN server up to the browser.

Visitors are not attracted to slow and dangerous websites. A CDN is essential for anyone who wants to grow and sustain their traffic. However, security should always be the top priority. To ensure a fast and secure user experience, follow the steps below.

How CDNs can protect your website from DDoS attacks

Although content delivery network services and solutions are often associated with speeding up web pages and improving page loading speeds, they can also help protect websites from DDoS attacks.

Providers of CDN solutions have modernized their security systems to protect their servers from DDoS attacks.

CDNs are a great way to protect your site from DDoS attacks.

Large Capacity to Handle High Traffic Volumes.

CDN solutions, which are built for handling unusually high traffic to websites by design, can be used to analyze and manage such traffic. This includes spikes in traffic due to natural phenomena such as marketing, sales and SEO campaigns. This ability to handle large volumes of traffic can also be useful in handling DDoS attacks that cause unnaturally high volumes of traffic. It is capable of absorbing the most severe DDoS attacks at low levels thanks to its IT infrastructure.

Proactive Monitoring and Cleaning Tools

It is not enough to simply have the ability to handle large volumes of traffic. Top CDN operators have many tools that can help websites protect themselves from various attacks. These tools provide proactive monitoring of possible attacks as well as the ability to inspect and cleanse traffic for harmful and unnatural visits.

Support for all Major TLS Extensions

TLS, or Transport Layer Security, is a protocol that authenticates your website and gives you data integrity, privacy, and security between the origin server, the CDN servers, and then the CDN servers and the end-user.

Cloudflare is a top CDN platform provider and supports all 5 major TLS extensions, including HTTP/2, OCSP Stapling Dynamic Record Sizing, ALPN and ALPN. This is a great choice for website owners looking to protect their web assets and improve page load speed to provide a better user experience.


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