Application Shield

Easily ensure secure, compliant and highly available web applications

CDNetworks Application Shield is always-on and inline, protecting your web assets all the time.

CDNetworks Application Shield technology provides a turnkey cloud-based Web Application Firewall solution to protect web applications from vulnerabilities and attacks. Integrated with our global CDN, our multi-layered WAF technology guarantees a secure and high performing web experience. The diagram below shows how our cloud WAF prevents web application attacks in real time.

CDNetworks Application Shield is always-on and inline, protecting your web assets all the time. With built-in intelligence, our WAF is constantly learning and protecting your web applications from new malicious actors and attack vectors, keeping your business safe and available.

Application Shield Benefits

Intelligent WAF

We deploy an intelligent web application firewall (WAF) technology that is fully integrated with our global CDN, monitored 24/7


Our Cloud Security technology is self-learning and self-evolving, providing fast and reliable remediation during attacks with a multi-layered approach

Free DDoS

Free DDoS mitigation included with Application Shield

Application Shield Features

OWASP top 10, 2017

Injections, XSS and other common threats

Specific Application Vulnerabilities

Automated creation of rules and virtual patches corresponding to a vulnerability scan

Rate Limitation

Create and enforce custom rate limitations

Quick Deployment

Protect HTTP/S traffic easily and immediately through a simple DNS configuration.


  • Unlimited application-layer DDoS attack mitigation
  • Network-layer DDoS attack mitigation without additional charges

Common Application Vulnerabilities

Virtual patching of popular CMS and Ecommerce platforms

Zero Day

Protect applications against new threats through an intelligent back-end monitoring, detecting and blocking unwanted behaviors

Access Control

Create custom rules to block traffic by IP, region, HTTP headers and more

Custom Signatures

Create customized rules and regular expression signatures through user-friendly rule wizards

Visual Dashboard

  • Full DDoS dashboard and log
  • Full WAF dashboard and incident log
  • View attack trends on a real-time dashboard, filter by domains, attack types, dates and more parameters

Application Shield Diagram

Application Shield Firewall Layers Diagram

What is a Web Application Firewall (WAF)?

A Web Application Firewall or WAF is a network security system that helps protect web applications from various types of attacks by making sure that a web server only receives legitimate traffic.

Firewalls are systems that monitor and control traffic that enters and leaves the network. It acts as a barrier between your network and the open internet.

A web application firewall is a specific type of firewall that focuses on the traffic going to and leaving web apps. Standard firewalls act as a first level of security but today’s websites and web services need more security. This is where WAFs provide specialized capabilities and thwarts attacks specifically aimed at the applications themselves.

How Does a Web Application Firewall (WAF) Work?

A WAF works by filtering, monitoring and blocking suspicious HTTP/s traffic between a web application and the internet.

Implementing traditional firewalls have been a basic cybersecurity practice for a while. These are deployed around networks and operate in the Layers 3 to 4 in the Open Systems Interconnection (OSI) Model.  Their role is limited to inspecting packets over the IP and TCP/UDP protocol and filtering traffic based on IP addresses, protocol types and port numbers.

A WAF on the other hand operates at Layer 7 (L7) of the OSI model and can understand web application protocols. They are essential to analyze traffic going to and from a web application and to prevent attacks that might otherwise go undetected through a traditional network firewall.

When a WAF is deployed, it acts as a reverse-proxy shield between an application and the internet. A proxy server is an intermediary that protects a client machine. Reverse-proxies on the other hand ensures that the clients pass through it before reaching a server. Crucially, a WAF can be used to protect multiple applications that it is placed in front of.

A WAF uses a set of rules called policies to filter out malicious traffic from taking advantage of application vulnerabilities. These security policies are often based on known web attack signatures, including scanpoints like HTTP Headers, HTTP Request Body and HTTP Response Body. The set of rules can also be specified to detect patterns in URL or file extension, to restrict URI, header and body length, to detect SQL/XSS injection and even bots based on their signature detection and behavior

The key benefit of using a WAF is that these policies can be modified and implemented quickly and with ease. Some WAF providers also provide functionalities for load balancing, SSL offloading and intelligent automation of these policy modifications using machine learning. This makes it easy to adapt and respond to varying attack vectors and for Distributed Denial of Service (DDoS) protection.

On its own, a WAF cannot protect against all attacks. But it can enhance web application security to protect against these common attacks:

Cross-site forgery

These are attacks which force authenticated users of a web application to take actions that compromise the security of the app. Usually, an attacker tricks the user to click on a link by sending them a link via email. Once the user authentication and logins are completed, the user can be forced to perform requests such as transferring funds, or changing their profile details and email addresses. If the attack is aimed at an admin account and becomes successful, it could compromise the entire web application.

Cross-site scripting

Cross-site scripting attacks are those where an attacker injects malware into a client’s browser to steal data including session cookies or edit the content to show false information. This usually happens when a dynamic website that contains scripts in JavaScript, PHP and .NET is injected with malicious code. When a user loads the web page, the attacker’s malicious scripts are executed. For example, the user’s cookie may be sent to the attacker who can use it for impersonation.

SQL injection

These are attacks where the attackers try to inject malicious SQL commands into websites and applications which have user-input data fields such as contact forms. The injected code can gain unauthorized access to databases and run commands to extract or modify private information contained in the databases.

What Are the Different Types of WAFs?

A WAF protects web applications by blocking attacks that satisfy certain pre-set criteria while allowing approved traffic. They help protect against cross-site forgery, cross-site scripting, SQL injection and file inclusion where attackers try to gain unauthorized access to an application to steal sensitive data or compromise the application itself.

A WAF can be one of three types based on the way they are implemented.

Network-based WAF

This is usually a hardware-based WAF and is installed locally. This means that it is placed close to the server and is therefore easier to access. As is the case with hardware-based deployments, they help minimize latency but can be expensive to store and maintain.

Host-based WAF

A host-based WAF is one that is fully integrated into an application’s software. It exists as a module inside the application server. This type of WAF is less expensive than a network-based WAF and is more customizable. On the downside, they can drain the local server resources and affect the performance of the application. They can also be complex to implement and maintain.

Cloud WAF

A Cloud-based WAF is more affordable and requires less on-premises resources to manage. They are easier to implement and often delivered as a SaaS by a vendor. offering a turnkey installation as simple as changing the DNS to redirect web traffic. Because of the cloud service model, they also have minimal upfront cost and can be continuously updated to keep up with the latest attacks in the threat landscape. CDNetworks offers a cloud-based WAF that is integrated with our global content delivery network (CDN) and prevents web application attacks in real time.

Web Application Firewall
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