Web Application Firewall

Digital transformation is driving more and more enterprises to migrate a large number of their services to the cloud. In the face of increasing frequency of Distributed Denial of Service (DDoS) and automation attacks against business processes, enterprises need to pay more attention to their web application (internal or external). To effectively protect against evolving threats, enterprises are looking for smart solutions that improve the detection and protection capabilities of their web applications. 

The first step? Implementing a Web Application Firewall (WAF) solution. 

A WAF is an application firewall for HTTP applications. Deployed on the front-end of servers, WAFs are the first line of defense to protect, monitor, and control access to web applications. It provides web security for HTTP applications from automated and targeted attacks such as SQL injection (SQLi), cross-site scripting (XSS), DDoS, etc. WAF helps web applications and APIs by filtering and monitoring HTTP traffic for security threats before it reaches the application server – considered as a reverse proxy. 

Why should organizations implement WAF?

Web applications are the most common method of compromise against any corporation with a digital presence. In recent years, web application security has increasingly been targeted by malicious actors. Global spending on web application security is predicted to reach $4.636 billion by 2022, as per a report by IDC Global Web Security Forecast

The primary function of WAF is to protect HTTP applications, including websites, API endpoints, and serverless functions. It can protect web applications from most known vulnerabilities such as OWASP Top 10 and enforce security policies and SSL security requirements.

  • Security

WAF serves as a front-end security for your website and focuses on HTTP code and the request procedures for other internet applications. It understands HTTP and HTTPs traffic better than any other traditional firewall. Cloud WAF works as a reverse proxy by design. They actively protect the transport layer security (TLS) suite that requires in-line traffic interception (man-in-the-middle) to decrypt. 

Note: WAF is only one layer of defense for a web application with layer 7 protocol. It is not designed to defend against all types of attacks. If WAF is not configured properly, it is easy to bypass it and compromise web applications. While WAF may not completely secure your systems, they provide reliable protection against “script-kiddies”.

  • User experience

Driven by cloud web application and API protection services, WAF solution is a growing market. Cloud-based WAFs are platform-agnostic and easy to configure. It addresses an enterprise’s needs to protect public and internal web applications while providing businesses, the flexibility to scale.

  • Complexity 

As web application continues to evolve, legacy rules-based web applications or traditional firewalls are no longer sufficient to address the complexity of modern web applications. WAFs, go beyond traditional firewalls to offer a proactive security mechanism that is scalable, robust, and easy to configure.

  • Compliance

Apart from threat prevention, WAFs help enterprises comply with regulatory standards. For instance, the Payment Card Industry Data Security Standard (PCI-DSS) mandates that web applications must pass a security assessment (Requirement 6.6). Compared to code reviews, setting up a WAF would be a quicker, efficient, and cost-effective way to meet regulatory requirements.

 

WAF Configuration Models

For WAFs to work, it needs to be a part of your web hosting protection strategy as a hardware or software solution. Web application firewalls can be configured according to three basic security models:

  • Whitelisting Model: WAFs are configured to allow only pre-approved traffic based on pre-configured criteria. For example, it can be configured to only allow HTTP requests from only certain pre-defined IP addresses. This model is harder to break and is best suited to protect internal networks.

Pros: Better performance with less false positives         

Cons: Longer implementation time

  • Blacklisting Model: WAFs are configured to block known vulnerabilities, attack signatures, and malicious entities from accessing the web application. It relies on a database of pre-set attack signatures to recognize and blacklist entities and secure the system. For example, if multiple requests are generated from a single IP address, the blacklisting WAF would label it as a DDoS attack. The blacklisting model is best suited for web applications on the public domains. However, compared to whitelisting, this model is easier to break and ineffective against 0-day attacks.

Pros: Takes less time to implement             

Cons: Provides less protection

  • Hybrid Model: WAFs are configured to dynamically respond to traffic based on the specific needs of the application. This model incorporates the best of whitelisting and blacklisting security methods to protect both, internal and public networks.

Note: A model’s effectiveness is determined based on the specific context, needs, and risk profile of the web server and application.

What if WAF is not in place?

In the absence of a WAF, your web application is vulnerable to attacks by malicious actors. Hackers can easily access business-critical information by performing an SQL injection, XSS, or perform application-specific attacks. 

If WAF is in place?

With WAF implementation, an enterprise is automatically protected from a range of attacks, with strong rule sets, and extensive customization with Layer 7 protection and DDoS mitigation.

A WAF is extremely beneficial for today’s digital enterprises. While it can’t protect you from all attacks, it does hinder the process of vulnerability search and exploitation. It plays a key role in a defense strategy to mitigate risks and optimize application security. 

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