WAF vs. RASP: What are the differences?

Both web application firewalls (WAFs) and runtime application self-protection (RASP) are web application security solutions. WAFs shield web applications from the internet, safeguarding the server by detecting and blocking malicious HTTP and HTTPS traffic to and from a web service. RASP solutions are instead directly integrated into an application’s runtime environment, allowing it to monitor behavior or activity that slipped by the first line of defense (the WAF). 

What is a WAF?

A Web Application Firewall (WAF) is a specialized security solution that shields a web application from the internet, safeguarding the server by detecting and blocking malicious HTTP and HTTPS traffic to and from a web service. 

When properly configured and enabled, a WAF prevents application-layer (Layer 7) attacks that exploit web application vulnerabilities, including those listed by OWASP, such as SQL injection, cross-site scripting (XSS), and HTTP protocol violations.

A WAF's primary function is to analyze HTTP conversations between clients and servers. This analysis examines vital components such as headers, bodies, and query parameters across all request types. The WAF identifies HTTP traffic that matches known attack patterns or violates established security rules. It then proactively blocks dangerous requests before they reach the application, thus safeguarding web apps.

How does a WAF work? 

WAFs often function as reverse proxies between the internet and protected web applications. However, you can also deploy WAFs in various configurations, including inline, cloud-based, or on-premises, to suit specific security requirements. Regardless of the deployment method, a WAF inspects all incoming traffic before it reaches application servers, creating a protective shield against potential threats.

What is RASP?

RASP solutions aim to deliver more targeted or specific protection to an organization’s applications. Rather than providing a wide ‘net’ of security like a WAF, RASP works by protecting a single application.  

How does RASP work?

RASP solutions monitor inputs, outputs, and the overall behavior of an application, identifying attacks based on changes in the application’s behavior. RASP works based on sensors that are embedded in an application (software). Using contextual information about the application, the sensors monitor the application while it is running (at runtime), and help to identify and stop any identified threats, in real-time.  

What are the benefits of WAF and RASP?

Benefits of WAF

A WAF should be part of any robust security program. They help provide protection against known vulnerabilities, handle large volumes of traffic, and good solutions require very little effort to get up and running. 

More specifically, the benefits of using a WAF include:

Data protection. WAFs intercept all incoming HTTP requests, helping to prevent unauthorized access and avoid data breaches. 

DDoS mitigation. WAFs can help protect web applications from distributed denial-of-service (DDoS) attacks. You can also use a dedicated DDoS solution for this. 

Protection against Application Layer Attacks. WAFs help block common application-layer attacks like SQL injection and cross-site scripting (XSS).

Compliance. WAFs help an organization remain compliant, with requirements like PCI DSS. 

Better overall security posture. WAFs are a great way to improve your overall security posture, preventing threats or vulnerabilities from impacting your org. 

Increased visibility. WAFs can help you get better insights into your web traffic and any potential threats. 

Access Control. WAFs can help you to enforce access controls, meaning unauthorized users/traffic can’t access your systems. 

Benefits of RASP

The key benefit of a RASP solution is that it adds an extra layer of security to your applications; any risk that attackers may have circumvented an org’s WAF are resolved with RASP. By monitoring activity directly within an application, RASP serves as a second layer of assurance that no one has made it past the firewall.

Specifically, some benefits include:

Zero-Day protection. RASP solutions help to identify zero-day attacks (unidentified or unknown vulnerabilities) that may slip by other security solutions. Because RASP monitors for abnormal behavior within the application, it can catch things other solutions may miss. 

Target defense. By integrating directly within the running application, RASP solutions help to provide targeted defenses for the application - an extra layer of security. This granular level of protection means an overall increase to your security posture. 

Real-time response. RASP monitors an application at runtime, meaning results are in direct response to real-time threats and events. This gives you real-time detection and response capabilities - a great asset to any security program. 

Lower costs. RASP solutions can help lower security costs, as they remove the need for multiple security tools. 

Should I use WAF and RASP together?

Though powerful, WAFs can unwittingly allow zero-day (new and unknown) attacks, no matter how well they function, or how comprehensive your WAF rules implementation.  That’s why it is a best practice for organizations to implement a multi-pronged approach to security, using both WAFs and RASP. 

In essence, WAFs function as a more traditional firewall, while RASP is like a security agent within the application itself. By using both, organizations can create a robust defense-in depth security strategy that strengthens their overarching security posture.

How Fastly can help

When choosing a WAF provider, it is essential to select one with global coverage, powerful detection, and integration capabilities tailored to modern infrastructure. 

Fastly's Next-Gen WAF is designed from the ground up with these features in mind. As the world's largest global edge cloud platform, it sits within milliseconds of users worldwide.

This strategic positioning allows Fastly to protect websites and applications faster than traditional WAFs. Inspecting traffic close to end users quickly limits the level threats can penetrate, helping to block attacks before they ever reach the origin servers.

Among its key benefits, Fastly's Next-Gen WAF provides:

• Comprehensive protection: Fastly detects and blocks the OWASP Top 10 web application vulnerabilities and custom threats you define through simple rules.

• Rapid response times: With its global network of POPs, Fastly's Next-Gen WAF ensures ultra-low latency inspection for exceptional user experience, even during attacks.

• Flexible configuration: You can customize rules, response pages, and more via Fastly's user-friendly interface without relying on lengthy change windows.

• Real-time analytics: Thanks to Fastly's dashboard and API for proactive issue identification, you benefit from valuable insights into traffic and security events.

Seamless integration: Fastly's Next-Gen WAF works transparently with its CDN and edge computing services for unified security, performance, and delivery capabilities.

Learn more about how the Fastly Next-Gen WAF can provide advanced protection for your applications, APIs, and microservices with flexible deployment options and cutting-edge detection capabilities.