AWS WAF (Web Application Firewall) and Application Security

Amazon’s AWS WAF web application firewall service is built specifically to protect cloud apps from a whole range of Internet threats. Learn how it works.

We all know that web applications are vulnerable to attacks, and that deploying your application from the cloud can theoretically expose it to even greater risk. To help secure their web apps, administrators will often use IDS (Intrusion Detection System) or IPS (Intrusion Prevention System) solutions, or a Web Application Firewall. In this post we’re going to focus on WAFs and, in particular, Amazon’s AWS WAF application-level firewall service.

Because it monitors traffic at the application layer, WAF will often be the preferred choice for securing your applications. Let’s see how it works, and how Amazon’s version can take it even further.

Categories of web attacks

Before talking about AWS WAF, it makes sense to review some of the more common vulnerabilities facing web applications.

  • DDoS attacks

This is probably the most common attack of them all. Attackers overload an application by sending bulk requests to the web servers. This slows down the application and makes it unavailable for genuine requests. This can significantly hurt the value of a brand and also affect business.

  • SQL injections

An attacker can run malicious SQL queries on websites or applications using SQL based databases. If the databases aren’t secured, attackers can access confidential account and business information.

Here’s an example of SQL injection:

SELECT id FROM users WHERE username=’username’ AND password=’passwordOR 1=1’

The above statement – even using an incorrect username or password – will always return a result.

  • Cross site scripting

If your application is vulnerable to cross site scripting then the attacker can run or inject malicious scripts, generally in the form of a browser side script. If your end user is accessing a vulnerable application, his browser has no way to know that the script should not be trusted, and will execute it. These scripts can even rewrite the content of the HTML page.

These threats should certainly give us some worry. But hey, all is not lost. The web application firewall is there to help. There are many WAF tools available on the market like ModSecurity, WebCastellum, OpenWAF, and Barracuda. But now there’s also AWS WAF.

What is AWS WAF?

Now, as we all know, AWS is riding on top of the cloud computing wave. Customers are migrating all kinds of applications to AWS’s infrastructure. But the basic challenges of security remain the same: how can you protect your web applications from all the vulnerabilities we’ve discussed (along with those we didn’t mention)? Can I use the traditional WAF tools with the cloud? Will they work with my AWS infrastructure?

Yes and yes. But let’s take it one step at a time. Let’s consider a simple use case. Imagine that you have an application with some web servers, app servers, and a database, all deployed in the AWS cloud. You’d obviously like to secure your application from web attacks. How should you proceed?

The traditional approach would be to set up a firewall in front of your web servers to monitor application traffic before it hits the servers. If you’re using AWS, then most probably, it would sit between Amazon’s load balancer and the servers. You could also place it in front of the load balancer.

Watch this short video which is part of the Cloud Academy’s Protecting Web Apps with AWS WAF, Shield & Firewall Manager Course.

 

Design considerations

  • Choosing an appropriate WAF solution and managing its availability can really drive you crazy.
  • Setup and configuration can be very complex.
  • Making sure your WAF solution can keep up with your application as it scales can be a challenge.
  • Web traffic monitoring may not be simple.

To address these issues, Amazon has given us AWS WAF, this will protect AWS-powered web applications served by AWS services like Amazon CloudFront from attacks happening at application layer.

AWS WAF is a web application firewall that helps protect your web applications from common web exploits that could affect application availability, compromise security, or consume excessive resources. AWS WAF gives you control over which traffic to allow or block to your web application by defining customizable web security rules.

How AWS WAF works

Now, instead of provisioning and maintaining your own WAF servers, you can just set up WAF from the AWS console. This will let you define your traffic filtering rules without needing to invest time ensuring proper configuration and availability.

To get started, you only need to create web ACLs. A web ACL contains at least one rule in which you specify conditions that will either block or allow incoming requests. Assuming you’re working with CloudFront, once the web ACL is ready, you can simply attach it to your application’s distribution. It’s important to understand a few key web ACL elements, like Conditions and Rules:

WAF Conditions

For your rules to work, you will need to specify the filter condition for your web ACL:
AWS WAF IP match conditions
AWS WAF SQL injection match conditions

WAF Rules

Once you are done with configuring conditions, you can create a rule and attach it to your web ACL. You can attach more than one rule to an ACL.
AWS WAF creating rulesA Web ACL, with conditions and rules, looks like this:
AWS WAF Web ACL example
AWS WAF Default action
You’re now ready to associate your new web ACL with an AWS service.

Pricing

With AWS WAF, you pay only for what you use. There are no minimum fees and no upfront commitments. Your costs will depend on three major variables:

  • Number of Web ACLs: each Web ACL will cost you $5/month.
  • Number of Rules: $1.00 per rule per web ACL per month.
  • Request Count: $0.60 per million web requests.

Things to know about AWS WAF

  • Since AWS WAF is integrated with AWS CloudFront – which supports custom origins outside of AWS – it can even be used to protect websites not hosted on AWS.
  • You can configure custom error pages.
  • Real time metrics can be monitored from CloudWatch.
  • AWS WAF can inspect HTTPS traffic.

I hope this post helped give you a clear picture of AWS’s Web application firewall and its implementation.

If you’ve got any thoughts of your own, why not add them to the comments?

Avatar

Written by

Vineet Badola

Working as a cloud professional for last 6 years in various organizations, I have experience in three of the most popular cloud platforms, AWS IaaS, Microsoft Azure and Pivotal Cloud Foundry PaaS platform. Having around 10 years of IT experience in various roles and I take great interest in learning and sharing my knowledge on newer technologies. Wore many hats as developer, lead, architect in cloud technologies implementation. During Leisure time I enjoy good soothing music, playing TT and sweating out in Gym. I believe sharing knowledge is my way to make this world a better place.


Related Posts

Alisha Reyes
Alisha Reyes
— April 9, 2020

New on Cloud Academy: AWS Solutions Architect – Associate Exam Prep, Azure Courses, Google Associate Cloud Engineer Exam Prep, Programming Labs, and Much More

Free content on Cloud Academy More and more customers are relying on our technology and content to keep upskilling their people in these months, and we are doing our best to keep supporting them. While the world fights the COVID-19 pandemic, we wanted to make a small contribution to he...

Read more
  • AWS
  • Azure
  • Google Cloud Platform
  • programming
Joe Nemer
Joe Nemer
— April 3, 2020

Breaking News: All AWS Certification Exams Now Available Online

Remote proctoring for all AWS certifications Cloud Academy is an Advanced AWS Technology Partner, and we are happy to announce all AWS certification exams are available online!  What does this mean for you? You can stay focused on your certification goal. Or you can start a certifica...

Read more
  • AWS
  • AWS certification
  • AWS Certifications
Connie Benton
Connie Benton
— April 1, 2020

How To Build a Career with AWS Certifications

From Iaas and PaaS solutions to digital marketing, cloud computing reshapes the world of technology. As the influence of this technology grows, so does investment. Tens of billions of dollars are being spent on cloud computing-related services each year. This influx is continuing to inc...

Read more
  • AWS
  • Certifications
Vijayakumar Athithan
Vijayakumar Athithan
— March 27, 2020

What is Cognito in AWS?

Web applications usually allow a valid username and password combination for successful sign in to the application. Modern authentication flows incorporate more approaches to ensure user authentication. When using AWS, this is no exception, thanks to the abilities and features offered b...

Read more
  • AWS
  • AWS Cognito
  • Solutions Architect
Avatar
Andrew Larkin
— March 20, 2020

The 12 AWS Certifications: Which is Right for You and Your Team?

As companies increasingly shift workloads to the public cloud, cloud computing has moved from a nice-to-have to a core competency in the enterprise. This shift requires a new set of skills to design, deploy, and manage applications in cloud computing. As the market leader and most ma...

Read more
  • AWS
  • AWS Certifications
Alisha Reyes
Alisha Reyes
— March 17, 2020

Cloud Academy’s Blog Digest: How Do AWS Certifications Increase Your Employability, How to Become a Microsoft Certified Azure Data Engineer, and more

With everything going on right now, it's likely that the only thing you've been reading lately is related to the coronavirus pandemic. It's important to stay informed during these times, but it's also good to jump into something that can take your mind off of the current situation for j...

Read more
  • AWS
  • Azure
  • blog digest
  • Certifications
  • Cloud Academy
  • programming
  • Security
Avatar
Cloud Academy Team
— March 13, 2020

Which Certifications Should I Get?

As we mentioned in an earlier post, the old AWS slogan, “Cloud is the new normal” is indeed a reality today. Really, cloud has been the new normal for a while now and getting credentials has become an increasingly effective way to quickly showcase your abilities to recruiters and compan...

Read more
  • AWS
  • Azure
  • Certifications
  • Cloud Computing
  • Google Cloud Platform
Alisha Reyes
Alisha Reyes
— March 7, 2020

New on Cloud Academy: Intro to GitOps; AWS Courses; Java, Python, Amazon Linux 2, Ubuntu, & Docker Playgrounds; and much more

New Lab Playgrounds This month, our Content Team released six new "playground labs." Our playground labs provide a safe and secure sandbox environment for you to explore your own ideas, follow along with Cloud Academy courses, or answer your own questions — all without having to instal...

Read more
  • AWS
  • Azure
  • gitops
  • Google Cloud Platform
  • lab playground
  • programming
Alisha Reyes
Alisha Reyes
— March 6, 2020

New on Cloud Academy: Intro to GitOps; AWS Courses; Java, Python, Amazon Linux 2, Ubuntu, & Docker Playgrounds; and much more

New Lab Playgrounds This month, our Content Team released six new "playground labs." Our playground labs provide a safe and secure sandbox environment for you to explore your own ideas, follow along with Cloud Academy courses, or answer your own questions — all without having to instal...

Read more
  • AWS
  • Azure
  • gitops
  • Google Cloud Platform
  • lab playground
  • programming
Patrick Navarro
Patrick Navarro
— March 4, 2020

AWS Certifications: How Do They Increase Your Employability and Progress Your Career?

AWS certifications are no walk in the park. They’re designed to validate in-depth, specialist knowledge and comprehensive experience, often requiring months of dedicated studying to earn even for those already working with the cloud platform. But the rewards that AWS professionals ca...

Read more
  • AWS
  • AWS certification
  • certification
Avatar
Chandan Patra
— February 21, 2020

Elasticsearch vs. CloudSearch: AWS Cloud Search Choices

Elasticsearch vs. CloudSearch: What's the main difference? Let's compare AWS-based cloud tools: Elasticsearch vs. CloudSearch. While both services use proven technologies, Elasticsearch is more popular, open source, and has a flexible API to use for customization; in comparison, CloudS...

Read more
  • AWS
  • Azure
  • cloudsearch
  • elasticsearch
Avatar
Andrew Larkin
— February 13, 2020

Cloud Academy Content Roadmap Updates

Welcome to our Q1 2020 roadmap. This is the content we plan to build over the next three months, between February 1 - and April 30, 2020. Let's look at some of our roadmap highlights. Atlassian Bamboo for CI/CD We had a lot of requests for practical guides on how to apply DevOps tool...

Read more
  • Artificial Intelligence
  • AWS
  • Azure
  • Docker
  • Google Cloud Platform
  • Kubernetes
  • Machine Learning