AWS Shared Responsibility Model – Amazon Web Services

Understanding the AWS Shared Responsibility Model is essential for aligning security and compliance obligations. The model delineates the division of labor between AWS and its customers in securing cloud infrastructure and applications. Under this framework, AWS guarantees the security of the cloud, encompassing physical infrastructure, networking, and virtualization layers, while customers safeguard their workloads, data, and configurations in the cloud. This segregation of duties streamlines operations, empowering organizations to innovate without compromising security.

This blog will examine the model’s core principles, key components, and the shifting responsibilities across different AWS services. Let us begin by defining the Shared Responsibility Model and its core purpose in the AWS ecosystem.

What is the Shared Responsibility Model?

The Shared Responsibility Model is a cloud security framework that outlines the security and compliance obligations of AWS and its customers. Under this framework, AWS assumes responsibility for securing the cloud infrastructure, encompassing physical facilities, network components, and virtualization layers. Meanwhile, customers are responsible for protecting resources within the cloud, including operating systems, applications, data, and the configuration of security controls such as Identity and Access Management (IAM) and security groups. The precise division of responsibilities varies by service model, with IaaS requiring more customer-controlled safeguards than higher-level PaaS or SaaS offerings. By clearly defining security of the cloud versus security in the cloud, the model helps organizations focus on their areas of accountability and streamline compliance efforts.

Having established what the Shared Responsibility Model entails, we can now examine its key elements in depth.

Elements of the AWS Shared Responsibility Model

The AWS Shared Responsibility Model partitions security and compliance tasks across distinct layers, ensuring clarity on which party is responsible for each component. At its core, the model distinguishes AWS’s duties for securing the underlying physical and virtual infrastructure from customers’ obligations to protect resources they deploy within the cloud. Security responsibilities encompass various elements, including physical data center protection, network and hypervisor security, operating system and application hardening, identity and access management, data classification and encryption, as well as logging and monitoring. Controls are further categorized as inherited, shared, or customer‑specific, guiding implementation and audit processes.

Security of the Cloud: AWS‑Managed Elements

1. Physical and Environmental Controls

AWS secures its global data centers with robust physical protections, including perimeter fencing, multi-factor entry, video surveillance, and environmental safeguards such as fire suppression and climate control.

2. Network and Virtualization Layers

AWS configures and maintains the network backbone, including routers, switches, and intrusion‑detection systems, alongside the virtualization stack (hypervisors and host OS) that isolates customer workloads.

3. Global Infrastructure Management

AWS ensures high availability through multiple Regions, Availability Zones, and edge locations, handling infrastructure updates, hardware maintenance, and compliance of the networking fabric.

Security in the Cloud: Customer‑Managed Elements

1. Data Protection and Encryption

Customers classify their data, select appropriate encryption methods (both at rest and in transit), manage keys via AWS Key Management Service (KMS) or external Hardware Security Modules (HSMs), and enforce access controls on storage services such as Amazon Simple Storage Service (S3) and Amazon DynamoDB.

2. Operating Systems and Applications

For IaaS offerings like EC2, customers install, configure, and patch guest operating systems and application software; they also implement vulnerability scanning, secure coding practices, and runtime hardening.

3. Identity and Access Management

Customers create and manage IAM users, roles, policies, and integrate MFA, SSO, and federated identities. AWS guarantees the availability and integrity of the IAM service itself, but customers are responsible for enforcing least-privilege access and credential rotation.

4. Network Configuration

Within VPCs, customers define subnets, configure security groups and network ACLs, manage route tables, and deploy host- and application-level firewalls or web application firewalls (WAFs) to segment and protect their workloads.

5. Logging and Monitoring

Customers enable and analyze CloudTrail, CloudWatch Logs, AWS Config Rules, GuardDuty, and Security Hub to detect configuration changes, anomalous activity, and compliance deviations in their environment.

Classification of IT Controls

1. Inherited Controls

Fully managed by AWS, customers inherit these protections. Examples include physical security, facility environmental controls, and baseline network infrastructure hardening.

2. Shared Controls

Responsibilities are split between AWS and the customer. For instance, AWS patches its infrastructure layers, while customers patch their guest operating systems and applications. AWS maintains device configurations, whereas customers configure their application environments. AWS trains its staff, while customers train theirs.

3. Customer‑Specific Controls

Solely the customer’s responsibility, such as implementing service and communication protection, zone security, data classification schemes, and application-level compliance controls.

Variation by Service Model

1. Infrastructure as a Service (IaaS)

AWS is responsible for the physical infrastructure, network, and virtualization; customers manage OS, middleware, runtime, applications, and data security.

2. Platform as a Service (PaaS)

AWS adds management of operating systems and runtimes; customers focus on application configuration, data encryption, and access controls.

3. Software as a Service (SaaS)

AWS handles nearly the entire stack; customers primarily manage user access, application-specific settings, and data governance.

With those elements clarified, it’s time to examine how responsibilities are distributed across different AWS service categories.

AWS Shared Responsibility Model Categorized by Service

Below is an examination of how AWS and its customers share security and compliance responsibilities across various cloud service models. We break down responsibilities for Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). For each model, AWS secures various components of the stack, ranging from physical data centers to application runtimes. At the same time, customers protect the layers they control, from operating systems and applications to data and user access.

Infrastructure as a Service (IaaS)

Infrastructure as a Service provides foundational building blocks like virtual machines, storage volumes, and networking delivered with high flexibility and control. Under IaaS, AWS secures the cloud components: physical facilities, network hardware, and the hypervisor that isolates customer workloads. AWS manages firmware, host operating systems, virtualization software, and physical security controls such as perimeter fencing, video surveillance, and environmental safeguards. Customers, meanwhile, secure in the cloud elements: they install, configure, and patch guest operating systems, apply middleware and application patches, and configure network controls like security groups and network ACLs. For example, when deploying an Amazon EC2 instance, customers are responsible for all guest OS updates, application security, and firewall settings, whereas AWS maintains the underlying compute infrastructure. This delineation ensures customers can tailor OS-level security and network segmentation without burdening AWS with workload-specific configurations.

Platform as a Service (PaaS)

Platform as a Service abstracts operating systems and runtimes, enabling customers to focus on application logic and data. AWS manages the underlying infrastructure, OS, and runtime components. For instance, within AWS Elastic Beanstalk, AWS automatically applies platform updates and patches across supported environments. Similarly, Amazon Relational Database Service (RDS) handles database engine patching, OS hardening, and underlying storage durability, while customers configure database users, schemas, and encryption settings. In these services, AWS secures middleware and runtime stacks, manages scaling, and ensures high availability across multiple Availability Zones. Customers retain responsibility for securing their application code, managing data encryption (both at rest and in transit), enforcing IAM policies for service access, and monitoring application-level logs. This shared approach reduces operational overhead, empowering developers to deploy features rapidly with AWS handling platform maintenance and compliance of foundational layers.

Software as a Service (SaaS)

Software as a Service offerings deliver fully managed applications, shifting nearly the entire security stack to AWS. Under SaaS, AWS is responsible for the application codebase, runtime environment, data storage infrastructure, and the continuous deployment pipeline. For services like Amazon QuickSight or AWS WorkDocs, AWS handles software updates, patch management, and infrastructure security, including the underlying servers and network configurations. Customers’ duties focus on data governance within the application, setting user permissions, managing sharing settings, and applying encryption or data classification policies. By inheriting core controls, such as physical security and network hardening, customers can focus on securing their files and user interactions, rather than managing these controls themselves. This minimizes administrative burden and accelerates time‑to‑value, while still enabling organizations to enforce least‑privilege access and meet specific compliance requirements at the application layer.

Conclusion

Mastering AWS’s Shared Responsibility Model enables businesses to effectively demarcate and manage security tasks, combining AWS’s infrastructure protections with customer-driven safeguards. By categorizing controls and adapting responsibilities across IaaS, PaaS, and SaaS, organizations can streamline compliance, mitigate risks, and accelerate innovation with confidence in their cloud environment.

If you want to dive deeper into AWS and build your expertise, you can explore the AWS Certification Training Course to gain a comprehensive understanding of AWS services, infrastructure, and deployment strategies. For more detailed insights, check out our What is AWS and AWS Tutorial. If you are preparing for an interview, explore our AWS Interview Questions.

FAQs

1. What is the AWS shared responsibility model?

It’s a security framework where AWS secures the cloud (hardware and infrastructure), and customers secure what they put in the cloud, including data, applications, operating systems, and configurations.

2. What is an example of AWS shared controls?

Patch management — AWS patches the infrastructure, while customers patch their operating systems and applications.

3. Which of the following are correct statements regarding the AWS shared responsibility model?

• AWS handles the infrastructure.
• Customers handle their data and apps.
• Responsibilities vary by service type, including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).
• Controls can be inherited, shared, or customized for specific customers.

4. What are the components of the AWS shared responsibility model?

• AWS-managed: Data centers, hardware, network, hypervisor
• Customer-managed: OS, data, IAM, app configs
• Control types: Inherited, shared, customer-specific