Enhancing AWS Security with Security Groups Chaining

Ayush Agrawal
5 min readAug 4, 2023

Amazon Web Services (AWS) provides a robust set of tools for securing your cloud infrastructure. One such powerful feature is Security Groups Chaining, which allows you to create a layered security approach by chaining multiple security groups together. This blog will explore the concept of Security Groups Chaining, and its benefits, and provide real-world examples of use cases where this security model proves valuable. We will also look at step by step implementation.

Understanding Security Groups Chaining

Security Groups Chaining involves linking multiple security groups to form a chain of security layers. Each security group is a set of inbound and outbound rules that control traffic to and from AWS resources, such as EC2 instances, load balancers, and RDS databases. By chaining security groups together, you can create more granular and customizable access controls, enhancing security while simplifying management.

Benefits of Using Security Groups Chaining

  1. Improved Security: Security Groups Chaining allows you to create a fine-grained network security model. Each security group in the chain can be tailored to specific requirements, minimizing the risk of unauthorized access and creating defence-in-depth.
  2. Simplified Rule Management: Rather than applying complex rules directly to resources, you can create individual security groups with specific rules. This simplifies rule management, making it easier to add or remove specific access permissions without impacting other resources.
  3. Granular Control: With Security Groups Chaining, you gain greater control over traffic flow. Different security groups in the chain can define varying levels of access, offering granular control over inbound and outbound traffic.
  4. Easy Scalability: As your AWS infrastructure grows, Security Groups Chaining scales effortlessly. You can add new security groups to the chain or adjust existing rules without affecting other components of the architecture.
  5. Auditable Access: Security Groups Chaining facilitates better auditing capabilities. Each security group in the chain serves as an additional layer of access control, enabling you to monitor and track traffic flow at different levels.

Examples of Use Cases

  1. Multi-Tier Web Application: Consider a multi-tier web application with frontend, application, and database layers. You can create separate security groups for each layer and chain them together. The frontend security group might allow inbound HTTP/HTTPS traffic from the internet, while the application security group permits access from the frontend group and the database group allows access from the application group. This ensures a clear segregation of traffic between layers, limiting unnecessary exposure and improving security.
  2. Load Balancer with Microservices: For a microservices-based architecture, you can create individual security groups for each microservice and chain them to the load balancer’s security group. This approach enforces strict access control for each microservice while enabling smooth traffic flow through the load balancer.
  3. DMZ and Internal Networks: In scenarios where you have a demilitarized zone (DMZ) and internal networks, Security Groups Chaining helps in implementing different levels of access control. Security groups for DMZ resources can allow limited access to internal network resources while maintaining strict security boundaries.

Step-by-Step implementation guide

Step-by-Step implementation guide for using Security Groups Chaining in a multi-tier architecture with web, application, and data layers in AWS:

Step 1: Sign in to AWS Management Console

Navigate to the AWS Management Console (https://aws.amazon.com/) and sign in to your AWS account.

Step 2: Create Security Groups

  1. Navigate to EC2 Dashboard: From the AWS Management Console, click on “Services” and then select “EC2” under the Compute section.
  2. Create Security Groups:
  • Create a Security Group for the Web Layer: Click on “Security Groups” in the left-hand navigation pane and then click on “Create Security Group.” Name it “Web-SG” and set the description accordingly. For the inbound rules, allow incoming traffic on ports 80 (HTTP) and 443 (HTTPS) from 0.0.0.0/0 (anywhere).
  • Create a Security Group for the Application Layer: Follow the same steps as above but name it “App-SG” and set the description accordingly. For the inbound rules, allow incoming traffic from “Web-SG” on the specific port(s) required for the application.
  • Create a Security Group for the Data Layer: Again, follow the same steps, name it “Data-SG,” and set the description accordingly. For the inbound rules, allow incoming traffic from “App-SG” on the specific port(s) required for the database connection.

Step 3: Chain Security Groups

  1. Edit Security Group Rules:
  • Select “Web-SG” and click on the “Inbound Rules” tab. Click on “Edit inbound rules.”
  • Add Inbound Rule: Click on “Add rule” and choose “Type” as “HTTP.” Set “Source” as “Anywhere,” and this allows traffic from the internet to the web layer.
  • Add Inbound Rule for HTTPS: Click on “Add rule” again and choose “Type” as “HTTPS.” Set “Source” as “Anywhere” to allow secure traffic from the internet.

2. Chain Security Groups for Application Layer:

  • Select “App-SG” and click on the “Inbound Rules” tab. Click on “Edit inbound rules.”
  • Add Inbound Rule: Click on “Add rule” and choose “Type” as “Custom TCP Rule.” Set the “Port Range” for the specific port(s) required for the application. Choose “Source” as “Security group ID” and select “Web-SG” from the dropdown. This allows traffic from the web layer to the application layer.

3. Chain Security Groups for Data Layer:

  • Select “Data-SG” and click on the “Inbound Rules” tab. Click on “Edit inbound rules.”
  • Add Inbound Rule: Click on “Add rule” and choose “Type” as “Custom TCP Rule.” Set the “Port Range” for the specific port(s) required for the database connection. Choose “Source” as “Security group ID” and select “App-SG” from the dropdown. This allows traffic from the application layer to the data layer.

Step 4: Apply Security Groups to Resources

  1. Associate Security Groups:
  • Launch EC2 Instances: Create EC2 instances for the web, application, and data layers, ensuring that they are placed in their respective subnets.
  • Associate Security Groups: When launching each instance, select the appropriate security group(s) for each layer. The web instances should have “Web-SG,” application instances should have both “Web-SG” and “App-SG,” and database instances should have “App-SG” and “Data-SG.”

Step 5: Test and Monitor

  1. Test Access: After applying the Security Groups Chaining, test access to your web application to ensure that traffic flows correctly between the chained security groups.
  2. Monitor Traffic Flow: Use AWS CloudWatch or other monitoring tools to track network traffic between the security groups. Regularly review and update security group rules based on your evolving requirements.

Security Groups Chaining offers a robust method to enhance AWS security by creating layered access controls for your resources. Its benefits, such as improved security, granular control, and simplified management, make it a valuable tool for architects and administrators. Through real-world examples, we demonstrated how Security Groups Chaining can be applied to various use cases, providing a scalable and auditable security model. By implementing Security Groups Chaining effectively, you can bolster the security posture of your AWS infrastructure, protecting critical assets from potential threats and vulnerabilities.

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Ayush Agrawal

Solutions Architect, AWS India, Founder of an Edtech startup(Acquired)