The Developer’s Guide To Palo Alto Networks Cloud NGFW for AWS

Photo by Glen Carrie on Unsplash

Busy modernizing your applications? One thing you can’t cut corners on is the security aspect. Today, we will discuss network security — inserting inbound, outbound, and VPC-to-VPC security for your traffic flows, to be precise, ​​without compromising DevOps speed and agility. When it comes to network security for cloud-native applications, it’s challenging to find a cloud-native security solution that provides the best in class NGFW security while consuming security as a cloud-native service. This means developers have to compromise security and find a solution that fits their development needs. That’s no longer the case — today, we will look at how you can have your cake and eat it too!

Infrastructure-as-Code is one of the key pillars in the application modernization journey, and there is a wide range of tools you can choose from. Terraform is one of the industry’s widely adopted infrastructure-as-code tools to shift from manual, error-prone provisioning to automated provisioning at scale. And, we firmly believe that it is crucial to be able to provision and manage your cloud-native security using Terraform next to your application code where it belongs. We have decided to provide launch day Terraform support for Palo Alto Networks Cloud NGFW for AWS with our brand new cloudngfwaws Terraform provider, allowing you to perform day-0, day-1, and day-2 tasks. You can now consume our Cloud NGFW with the tooling you are already using without leaving the interfaces you are familiar with; it’s that simple!

Getting Started

Prerequisites

AWS Architecture

We will focus on securing an architecture similar to the topology below. Note the unused Firewall Subnet — later, we will deploy the Cloud NGFW endpoints into this subnet and make the necessary routing changes to inspect traffic through the Cloud NGFW.

Application Architecture

Authentication and Authorization

Enable Programmatic Access

To use the Terraform provider, you must first enable the Programmatic Access for your Cloud NGFW tenant. You can check this by navigating to the Settings section of the Cloud NGFW console. The steps to do this can be found here.

You will authenticate against your Cloud NGFW by assuming roles in your AWS account that are allowed to make API calls to the AWS API Gateway service. The associated tags with the roles dictate the type of Cloud NGFW programmatic access granted — Firewall Admin, RuleStack Admin, or Global Rulestack Admin.

The following Terraform configuration will create an AWS role which we will utilize later when setting up the cloudngfwaws Terraform provider.

Setting Up The Terraform Provider

In this step, we will configure the Terraform provider by specifying the ARN of the role we created in the previous step. Alternatively, you can also specify individual Cloud NGFW programmatic access roles via lfa-arn, lra-arn, and gra-arn parameters.

Note how Terraform provider documentation specifies Admin Permission Type required for each Terraform resource as Firewall, Rulestack, or Global Rulestack. You must ensure the Terraform provider is configured with an AWS role(s) that has sufficient permission(s) to use the Terraform resources in your configuration file.

Rulestacks and Cloud NGFW Resources

There are two fundamental constructs you will discover throughout the rest of this article — Rulestacks and Cloud NGFW resources.

A rulestack defines the NGFW traffic filtering behavior, including advanced access control and threat prevention — simply a set of security rules and their associated objects and security profiles.

Cloud NGFW resources are managed resources that provide NGFW capabilities with built-in resilience, scalability, and life-cycle management. You will associate a rulestack to an NGFW resource when you create one.

Deploying Your First Cloud NGFW Rulestack

First, let’s start by creating a simple rulestack, and we are going to use the BestPractice Anti Spyware profile. BestPractice profiles are security profiles that come built-in, which will make it easier for you to use security profiles from the start. If required, you can also create custom profiles to meet your demands.

The next step is to create a security rule that only allows HTTP-based traffic and associate that with the rulestack we created in the previous step. Note that we use the App-ID web-browsing instead of traditional port-based enforcement.

Committing Your Rulestack

Once the rulestack is created, we will commit the rulestack before assigning it to an NGFW resource.

Note: cloudngfwaws_commit_rulestack should be placed in a separate plan as the plan that configures the rulestack and its contents. If you do not, you will have perpetual configuration drift and need to run your plan twice so the commit is performed.

Deploying Your First Cloud NGFW Resource

Traffic to and from your resources in VPC subnets is routed through to NGFW resources using NGFW endpoints. How you want to create these NGFW endpoints is determined based on the endpoint mode you select when creating the Cloud NGFW resource.

  • ServiceManaged — Creates NGFW endpoints in the VPC subnets you specify
  • CustomerManaged — Creates just the NGFW endpoint service in your AWS account, and you will have the flexibility to create NGFW endpoints in the VPC subnets you want later.

In this example, we are going to choose the ServiceManaged endpoint mode. Also, notice how we have specified the subnet_mapping property. These are the subnets where your AWS resources live that you want to protect.

In production, you may want to organize these Terraform resources into multiple stages of your pipeline — first, create the rulestack and its content, and proceed to the stage where you will commit the rulestack and create the NGFW resource.

At this point, you will have a Cloud NGFW endpoint deployed into your Firewall subnet.

You can retrieve the NGFW endpoint ID to Firewall Subnet mapping via cloudngfwaws_ngfw Terraform data resource. This information is required during route creation in the next step.

Routing Traffic via Cloud NGFW

The final step is to add/update routes to your existing AWS route tables to send traffic via the Cloud NGFW. The new routes are highlighted in the diagram below. Again, you can perform this via aws_route or aws_route_table Terraform resource.

Learn more about Cloud NGFW

In this article, we discovered how to deploy Cloud NGFW in the Distributed model. You can also deploy Cloud NGFW in a Centralized model with AWS Transit Gateway. The Centralized model will allow you to run Cloud NGFW in a centralized “inspection” VPC and connect all your other VPCs via Transit Gateway.

We also discovered how to move away from traditional port-based policy enforcement and move towards application-based enforcement. You can find a comprehensive list of available App-IDs here.

There is more you can do with Cloud NGFW.

  • Threat prevention — Automatically stop known malware, vulnerability exploits, and command and control infrastructure (C2) hacking with industry-leading threat prevention.
  • Advanced URL Filtering — Stop unknown web-based attacks in real-time to prevent patient zero. Advanced URL Filtering analyzes web traffic, categorizes URLs, and blocks malicious threats in seconds.

Cloud NGFW for AWS is a regional service. Currently, it is available in the AWS regions enumerated here. To learn more, visit the documentation and FAQ pages. To get hands-on experience with this, please subscribe via the AWS Marketplace page.

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Migara Ekanayake

Migara Ekanayake

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Interested in all-things-automation, cyber security, and programming languages