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Palo Alto WAF vs. AWS WAF vs. open-appsec WAF

Troy Hunt, the founder of Have I Been Pwned, has made the following observation:

“The success of a web application is based on having cutting-edge technology and providing a solution resistant to the never-ending battle of evolving threats we face. The only way to stay ahead is to continuously update our knowledge and be aware of new threats."

We agree with Troy; however, just relying on updating our knowledge of new threats might not be the total solution for protecting our web applications.

A more practical approach would be deploying a Web Application Firewall (WAF) that provides a holistic security approach to defending our web apps against known and unknown attacks. Hence, this would keep our apps safe and secure and also ensure smooth content delivery.

Read this article to get all the information you need to choose between Palo Alto WAF, AWS WAF, and open-appsec WAF, which is a contemporary open-source WAF with machine learning capabilities.

We’ll start by comparing the three WAFs.

Difference Between Palo Alto WAAS, AWS WAF, and open-appsec WAF: A Tabular Comparison


Palo Alto Web Application and API Security (WAAS)


open-appsec WAF

Machine-Learning App Security Approach

Not available

Not available natively but can be acquired through the AWS marketplace

Leverages machine learning techniques for safeguarding web applications and APIs

Type of System Configuration Used

Uses Web UI

System configuration is carried out using managed and custom rules in the Web UI

Uses declarative configuration and WebUI (SaaS)

System Maintenance Complexity

Complex system maintenance due to its use of rules and exceptions

Complex system maintenance due to the need for fine-tuning caused by policies, rules, and exceptions

Simple system maintenance due to the absence of rules, policies, and exceptions

Intrusion Prevention System

Not available

Not available natively but can be acquired through the AWS marketplace

Uses an open-source Snort 3.0 engine and an NSS-certified intrusion prevention system

Free Version and Pricing

No free version, but it offers a free trial

Need to contact them to get a pricing quotation

No free version, but it offers a 30-day free trial

AWS WAF pricing is based on three factors:

  1. 1. The number of Access Control Lists (ACL)

  2. 2. The number of rules you add to the ACLs

  3. 3. The number of incoming web requests

Offers a free, open-source version

Pricing plan consists of two paid versions: Premium and Enterprise Edition


Not open-sourced

Not open-sourced


Malicious Bot Prevention

Uses custom bot rules to identify and protect against bot attacks

Has a managed bot rule group called Fraud Control Account Takeover Prevention (ATP) to protect against malicious bot attacks

Uses machine learning models and app behavioral analysis to identify malicious bot traffic

Web Latency

Doesn’t increase web latency

Doesn't increase web latency

Doesn’t increase web latency

Zero-Day Detection

No feature dedicated to protecting web apps against zero-day attacks

Doesn’t effectively protect against zero-day attacks

Uses offline and online machine learning models and advanced threat prevention techniques to protect web apps against zero-day attacks

False Positives

Doesn’t detect a lot of false positives

Doesn’t detect a lot of false positives

Its second online and unsupervised machine learning model is dedicated to eliminating false positives

What Is Palo Alto WAF?

Palo Alto WAAS tool is a web application security tool that protects cloud-native applications and API. At its core, Palo Alto WAAS was designed to protect web applications and APIs deployed in public or private cloud architectures. It also safeguards applications and APIs deployed directly on hosts, as containers, application embedded, or serverless functions. It uses both agent-based and agentless deployment for cloud-native applications.

Moreover, the Palo Alto WAAS tool provides three essential elements to the web applications and APIs they cover: OWASP Top 10, DOS, and BOT protection, which provides your web applications a well-rounded layer of defense against today's threats. It does this by allowing its users to set rules, policies, and exceptions that can be used to monitor web traffic and block malicious ones. It also provides in-depth visibility into request activities in an app environment, making it an efficient threat management tool.

Features of Palo Alto WAAS

  • OWASP Top 10 Protection As highlighted earlier, Palo Alto's WAAS offers protection against the OWASP Top 10 attacks by allowing its users to create customizable rules and corresponding actions to requests that contain these threats. It identifies and protects web-facing services and API from attacks, supports auto-scaling, and OWASP Top 10 protection in ephemeral environments, ensuring effective and adaptable security.

  • API Security Palo Alto's WAAS provides precise, customizable web application and API security rules, including protection against API-related Layer 7 threats. It provides access control based on geo-location or IP and uses OpenAPI, Swagger files, or manual customization to ensure secure API behavior. Additionally, through file upload controls and file extension whitelist, it ensures a safe transfer of files. It profiles API risks to identify and prioritize vulnerabilities. Finally, it allows its users to customize alerts and attack-blocking options to create tailored security for APIs.

  • Bot Risk Management This feature offers visibility into bot activities, discerning between good and bad bots. Palo Alto WAAS alerts and blocks suspicious bot movements, including headless browsers, web scraping, credential stuffing, etc. It offers the option to allow, audit, block, and ban different bot categories, giving granular control over them. It does this by using static and active methods to detect bots. Its static detection method examines incoming HTTP requests and analyzes them to determine whether it was sent by a bot. While its active detection uses Javascript and Prisma Session Cookies to detect and classify bots.

What Is AWS WAF?

AWS WAF is an effective security solution that protects web applications and APIs using policies, managed and custom rules, and exceptions. One major advantage of AWS-managed rules is that once configured, it allows IT security teams to concentrate on code development.

Additionally, AWS WAF allows for flexibility in rule formation, where users can create custom rules and policies using either a visual rule builder or JSON code. This grants you granular control over your web app's security and allows you to create tailored defenses to your app's unique needs. Plus, AWS WAF offers a rate-limiting feature for pervasive bots and a dashboard that provides real-time visibility into bot activities, allowing users to isolate and block harmful bot traffic.

Features of AWS WAF

  • Web Traffic Filtering AWS WAF allows rule creation that monitors incoming traffic to your web server, ensuring a safer app environment. These rules, based on IP addresses, HTTP headers, bodies, or custom URLs, protect apps from attacks and vulnerabilities. Moreover, AWS WAF allows users to reuse rules across applications, providing efficient and consistent defense against common exploits.

  • Account Takeover Fraud Prevention (ATP): This feature monitors an app's login page to detect unauthorized access and prevent security breaches. It checks incoming requests against a database of stolen credentials to safeguard against attacks like credential stuffing, brute force attempts, and other login page attacks. It also tracks the success and failure rates of login attempts, using this data to block suspicious IP addresses or client sessions temporarily. ATP operates asynchronously, ensuring web latency remains unaffected.

  • Real-Time Visibility This feature offers real-time metrics on app traffic activity, including IP addresses, geo-locations, URLs, User-Agents, and referrers. It can be integrated with Amazon CloudWatch and allows users to set alarms when rule thresholds are exceeded or specific attacks occur. This integration records allowed, blocked, and passed requests every two weeks, ensuring that users have comprehensive visibility into their application's traffic and potential threats.

Pros and Cons of the AWS WAF



Doesn't increase web latency

Complex troubleshooting process

Provides effective protection against DDoS attacks

Complex configuration and documentation process

Offers tailored web application security using managed and custom rules

A lot of add-on options can lead to an increase in spending

open-appsec WAF

Are you looking for a way to block attacks on your web application before they happen? Look no further, as open-appsec uses machine learning to continuously detect and preemptively block threats before they can do any damage. Its code has also been published on GitHub, and the effectiveness of its WAF has been successfully proven in numerous tests by third parties. Try open-appsec in the Playground today.

This is an open-source WAF that uses machine learning to detect and block malicious requests accurately, with minimal false positives. It is user-friendly, scalable, and can be installed as an extension to NGINX reverse proxy, a Kubernetes Ingress Controller, Envoy, or API Gateways. It also supports integration with GraphQL, Terraform, and Helm.

Furthermore, open-appsec WAF protects web apps against OWASP Top 10 threats, common web application and API attacks, and zero-day exploits. It ensures simplified WAF maintenance as it eliminates the need for signatures and exception handling, which are common in traditional WAFs.

Now we'll explore its unique features in more detail.

Features of open-appsec WAF

  • Machine-Learning Threat Prevention With this feature, open-appsec WAF proactively safeguards against OWASP Top 10 attacks and zero-day threats, like Log4Shell and Spring4Shell, without the need for system updates or signatures. This eliminates the constant fine-tuning or exception handling often seen in traditional WAFs. It ensures the safety of web apps and APIs using two machine learning models – supervised and non-supervised. The supervised model operates offline, trained with millions of malicious and benign requests. This large amount of data enables the model to distinguish between legitimate and malicious requests, offering protection against known attacks. On the other hand, the non-supervised model operates online and performs its analyses in real-time. It uses contextual analysis to examine requests, considering factors such as the application's structure and user activity within the web app. This model learns how users typically interact with your web app and uses this knowledge to identify requests that deviate from normal operations. Both models contribute to open-appsec WAF’s continuous analysis of HTTP/S requests within your web apps and APIs, marking requests as malicious or benign based on transaction user behavior, crowd behavior, and content risks.

  • API Discovery and Security open-appsec WAF uses machine learning and OpenAPI schema validation to unveil all your APIs and harden your app's attack surface. It ensures that your API's activities are within secure confines. It aims to concentrate your security team's efforts and resources on specified APIs to enhance vulnerability management. This subsequently increases security and reduces potential API threats, improving your system's overall security.

  • Infrastructure-As-A-Code and API This open-appsec WAF feature simplifies deployment, updates, and configuration in cloud-native environments. It seamlessly integrates into an application's CI/CD pipeline, using declarative infrastructure-as-code or API. It also offers flexible management options and can be configured and controlled through declarative configuration. Additionally, it can be deployed and managed using Helm Charts, Kubernetes Annotations, Terraform, or extensive GraphQL API.

Pros and Cons of open-appsec WAF



Simplifies system maintenance by removing the need for managing rules and threat signatures

Is a fairly new WAF

Has a free version

Has a medium-sized community


Offers preemptive protection against attacks

Our verdict

Palo Alto WAAS is best known for its effective security against OWASP Top 10 attacks and other known attacks and its swift integration with the wider Prisma product set. AWS WAF provides lots of flexible security options through its AWS marketplace, while open-appsec WAF protects against known, unknown, and zero-day attacks.

Frequently Asked Questions

Does Palo Alto Firewall have a WAF?

Palo Alto Networks offer a firewall named Palo Alto Next-Generation Firewall and a web application firewall called Palo Alto Web Application and API Security.

What is the difference between Palo Alto NGFW and WAF?

Palo Alto's Next-Generation Firewall (NGFW) provides network-level security, focusing on traffic flow, intrusion prevention, and identifying and controlling applications and users based on deep packet inspection.

On the other hand, Palo Alto's Prisma Cloud Web Application and API Security (WAAS) serves as a web application firewall (WAF), focusing specifically on HTTP/HTTPS traffic, protecting web apps and APIs from common exploits and threats.

The NGFW generally delivers broad network protection, while the WAAS provides more specialized web application and API protection.

Is WAF outdated?

The concept of using Web Application Firewalls (WAF) to ensure app security is not outdated. However, traditional WAFs may struggle to keep up with the evolving landscape of web application threats and the complexity of modern applications.

Today, the focus is on contemporary WAFs like open-appsec, which uses advanced techniques like machine learning, AI, and behavioral analysis to better protect against threats. These contemporary WAFs are designed to handle the complexities of modern web applications, APIs, and microservices architecture, and to fend off zero-day attacks.


Experiment with open-appsec for Linux, Kubernetes or Kong using a free virtual lab

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