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AWS Firewall Manager helps automate security group management: 3 scenarios
In this post, we walk you through scenarios that use AWS Firewall Manager to centrally manage security groups across your AWS Organizations implementation. Firewall Manager is a security management tool that helps you centralize, configure, and maintain AWS WAF rules, AWS Shield Advanced protections, and Amazon Virtual Private Cloud (Amazon VPC) security groups across AWS Organizations.
A multi-account strategy provides the highest level of resource isolation, and helps you to efficiently track costs and avoid running into any API limits. Creating a separate account for each project, business unit, and development stage also enforces logical separation of your resources.
As organizations innovate, developers are constantly updating applications and, in the process, setting up new resources. Managing security groups for new resources across multiple accounts becomes complex as the organization grows. To enable developers to have control over the configuration of their own applications, you can use Firewall Manager to automate the auditing and management of VPC security groups across multiple Amazon Web Services (AWS) accounts.
Firewall Manager enables you to create security group policies and automatically implement them. You can do this across your entire organization, or limit it to specified accounts and organizational units (OU). Also, Firewall Manager lets you use AWS Config to identify and review resources that don’t comply with the security group policy. You can choose to view the accounts and resources that are out of compliance without taking corrective action, or to automatically remediate noncompliant resources.
Scenarios where AWS Firewall Manager can help manage security groups
Scenario 1: Central security group management for required security groups
Let’s consider an example where you’re running an ecommerce website. You’ve decided to use Organizations to centrally manage billing and several aspects of access, compliance, security, and sharing resources across AWS accounts. As shown in the following figure, AWS accounts that belong to the same team are grouped into OUs. In this example, the organization has a foundational OU, and multiple business OUs—ecommerce, digital marketing, and product.
Figure 1: Overview of ecommerce website
The business OUs contain the development, test, and production accounts. Each of these accounts is managed by the developers in charge of development, test, and production stages used for the launch of the ecommerce website.
The product teams are responsible for configuring and maintaining the AWS environment according to the guidance from the security team. An intrusion detection system (IDS) has been set up to monitor infrastructure for security activity. The IDS architecture requires that an agent be installed on instances across multiple accounts. The IDS agent running on the Amazon Elastic Compute Cloud (Amazon EC2) instances protects their infrastructure from common security issues. The agent collects telemetry data used for analysis, and communicates with the central IDS instance that sits in the AWS security account. The central IDS instance analyzes the telemetry data and notifies the administrators with its findings.
For the host-based agent to communicate with the central system correctly, each Amazon EC2 instance must have specific inbound and outbound ports and specific destinations defined as allowed. To enable our product to focus on their applications, we want to use automation to ensure that the right network configuration is implemented so that instances can communicate with the central IDS.
You can address the preceding problem with Firewall Manager by implementing a common security group policy for required accounts. With Firewall Manager, you create a common IDS security group in the central security account and replicate it across other accounts in the ecommerce OU, as shown in the following figure.
Figure 2: Security groups central management with Firewall Manager
Changes made to these security groups can be seamlessly propagated to all the accounts. The changes can be tracked from the Firewall Manager console as shown in figure 3. Firewall Manager propagates changes to the security groups based on the tags attached to the Amazon EC2 instance.
As shown in figure 3, with Firewall Manager you can quickly view the compliance status for each policy by looking at how many accounts are included in the scope of the policy and how many out of those are compliant or non-compliant. Firewall Manager is also integrated with AWS Security Hub, which can trigger security automation based on findings.
Figure 3: Firewall Manager findings
Scenario 2: Clean-up of unused and redundant security groups
Firewall Manager can also help manage the clean-up of unused and redundant security groups. In a development environment, instances are often terminated post testing, but the security groups associated with those instances might remain. We want to only remove the security groups that are no longer in use to avoid causing issues with running applications.
Figure 4: Ecommerce OU, accounts, and security groups
In our example, developers are testing features in a test account. In this scenario, once the testing is completed, the instances are terminated and the security groups remain in the account. The preceding figure shows unused security groups like Test1, Test2, and Test3 in the test account.
A Firewall Manager usage audit security group policy monitors your organization for unused and redundant security groups. You can configure Firewall Manager to automatically notify you of unused, redundant, or non-compliant security groups, and to automatically remove them. These actions are applied to existing and new accounts that are added to your organization.
Scenario 3: Audit and remediate overly permissive security groups across all AWS accounts
The security team is responsible for maintaining the security of the AWS environment and must monitor and remediate overly permissive security groups across all AWS accounts. Auditing security groups for overly permissive access is a critical security function and can become inefficient and time consuming when done manually.
You can use Firewall Manager content audit security group policy to provide auditing and enforcement of your organization’s security policy for risky security groups, most commonly known as allowed or blocked security group rules. This enables you to set guardrails and monitor for overly permissive rules centrally. For example, we set an allow list policy to allow secure shell access only from authorized IP addresses on the corporate network.
Firewall Manager enables you to create security group policies to protect all accounts across your organization. These policies are applied to accounts or to OUs that contain specific tags, as shown in figure 5. Using the Firewall Manager console, you can get a quick view of the non-compliant security groups across accounts in your organization. Additionally, Firewall Manager can be configured to send notifications to the security administrators or automatically remove non-compliant security groups.
In the policy scope, you can choose the AWS accounts this policy applies to, the resource type, and which resource to include based on the resource tags, as shown in figure 5.
Figure 5: Edit tags for policy scope
Conclusion
This post shares a few core use cases that enable security practitioners to build the capability to centrally manage security groups across AWS Organizations. Developers can focus on building applications, while the audit and configuration of network controls is automated by Firewall Manager. The key use cases we discussed are:
- Common security group policies
- Content audit security groups policies
- Usage audit security group policies
Firewall Manager is useful in a dynamic and growing multi-account AWS environment. Follow the Getting Started with Firewall Manager guide to learn more about implementing this service in your AWS environment.
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