The AWS Shared Responsibility Model is a foundational concept for anyone deploying workloads on Amazon Web Services. It defines the distribution of security duties between AWS and its customers, helping teams design controls, manage risk, and meet compliance requirements. At a high level, AWS is responsible for security “of the cloud” — the infrastructure, services, and foundational components — while customers are responsible for security “in the cloud” — their data, identities, applications, and configurations. From governance to day-to-day operations, understanding this division is critical to building a resilient cloud environment.

What the AWS Shared Responsibility Model Covers

The model covers the entire stack from hardware and facilities to software and data. It clarifies that the exact split of responsibilities depends on the AWS service model you choose. The core principle remains the same: AWS secures the infrastructure and managed services, and customers secure what they put in the cloud and how they use the services.

AWS Responsibilities: Security of the Cloud

AWS takes primary responsibility for the security of the cloud itself. This includes physical security of data centers, hardware, infrastructure, and the foundational services that support your workloads. Specifically, AWS manages:

• Physical facilities and hardware: buildings, servers, storage devices, power, cooling, and physical access controls.
• Foundational software and virtualization layers: hypervisors, core network components, and the security of AWS-managed services (e.g., IAM, S3, EC2, RDS) as 제공되는;
• Security of the cloud services’ controls: patching of the underlying platform, baseline configurations, and service-level protections that apply to the managed services themselves.
• Compliance for the underlying infrastructure: AWS maintains certifications and audits for the cloud environment and provides evidence to customers as needed.

In practice, this means that when you spin up an EC2 instance, AWS handles the security of the physical host, the virtualization layer, and the AWS-managed services. The specifics can vary by service model, which is why it is important to understand how the division shifts across IaaS, PaaS, and SaaS offerings.

Customer Responsibilities: Security in the Cloud

Customers own responsibility for the parts of the stack they control. This includes data classification, encryption, access control, application security, and network configurations. In concrete terms, customers are responsible for:

• Data protection: encryption at rest and in transit, data loss prevention, and data lifecycle management.
• Identity and access management: defining roles, least-privilege access, MFA, and secure credential handling.
• Platform and application security: securing guest operating systems (when applicable), patch management for customer-managed software, and secure development practices.
• Network security: configuring VPCs, subnets, security groups, route tables, and firewall rules to control traffic flow.
• Logging, monitoring, and incident response: enabling and supervising logs (e.g., CloudTrail, CloudWatch), alerting, and response processes.
• Compliance and governance: maintaining policies, risk assessments, and evidence for audits, including data residency and retention requirements.

For different service models, the line between AWS and customer responsibilities shifts. In IaaS (e.g., EC2), customers handle more of the guest OS and application security. In PaaS (e.g., RDS, Elastic Beanstalk), AWS assumes more responsibility for the runtime environment, while customers still protect their data and manage access and configuration. In SaaS offerings (e.g., Amazon WorkSpaces or some third-party SaaS on AWS), AWS covers much of the stack, but customers remain accountable for data governance and user access.

How the Model Applies Across AWS Services

The exact split is service-dependent. Here are a few practical examples to illustrate how the AWS Shared Responsibility Model scales across service categories:

• IaaS (Infrastructure as a Service) such as EC2 and EBS: AWS manages the security of the cloud infrastructure; you manage the operating system, middleware, and applications in the guest environment, along with data protection and access control.
• PaaS (Platform as a Service) such as RDS, Elastic Beanstalk, or Lambda: AWS handles more of the runtime and platform security; you focus on data, access policies, and the security of your applications and integrations.
• SaaS (Software as a Service) delivered on AWS: AWS handles the majority of the stack; you are responsible for configuring security settings for your users, data handling, and integration with other systems.

Recognizing these differences helps teams design blueprints that align with service choices. It also informs how you implement compliance controls, risk assessments, and vendor risk management across the cloud estate.

Key Areas of Responsibility Within the AWS Shared Responsibility Model

Identity and Access Management (IAM)

Identity and access control are among the most critical controls in the AWS Shared Responsibility Model. Implement least-privilege policies, enforce multi-factor authentication, rotate credentials, and use role-based access rather than long-lived user credentials. Regularly review access logs and implement break-glass procedures for emergency access.

Data Protection

Protect data both at rest and in transit. Choose appropriate encryption mechanisms, manage keys securely (for example, with AWS Key Management Service), and establish data classification schemes. Consider data lifecycle policies and backup strategies aligned with regulatory requirements.

Network Security

Design network architectures that segment workloads, apply strict ingress/egress controls, and minimize exposure. Use VPCs, subnets, security groups, network ACLs, and private connectivity where appropriate. Regularly test configurations and monitor anomalous traffic patterns.

Application and OS Security

For customer-managed resources, ensure timely patching of operating systems and applications, secure software development practices, and vulnerability scanning. When using PaaS or SaaS, rely on the provider for platform security while validating your own data handling and access configurations.

Monitoring, Logging, and Incident Response

Enable comprehensive monitoring and logging. Use AWS services like CloudTrail for API activity, CloudWatch for metrics, and GuardDuty for threat detection. Establish incident response playbooks, train teams, and regularly run tabletop exercises to validate readiness.

Compliance and Governance

Translate regulatory requirements into cloud-specific controls. Maintain an up-to-date control framework, perform regular audits, and leverage AWS compliance programs and artifacts. Documentation, evidence collection, and change management processes are crucial to demonstrate adherence to standards.

Shared Controls and Compliance Programs

AWS supports a broad range of compliance programs and provides controls that are shared with customers. This means AWS can provide the framework, tooling, and evidence for many controls, while customers must implement and validate the data, access, and configuration controls specific to their workloads. A solid governance model—comprising policy definitions, risk assessments, and independent reviews—helps ensure alignment with industry standards such as ISO 27001, PCI DSS, HIPAA, or GDPR.

Practical Steps to Align with the AWS Shared Responsibility Model

1. Map your workload to the appropriate service model (IaaS, PaaS, SaaS) to identify who owns which controls.
2. Define data classifications and data handling requirements from the outset.
3. Implement a robust IAM strategy with least privilege, MFA, and regular access reviews.
4. Encrypt sensitive data at rest and in transit; manage keys securely.
5. Design network architectures with segmentation, least exposure, and defense-in-depth.
6. Enable comprehensive logging and monitoring, and integrate alerts with incident response processes.
7. Establish governance and change-management practices that align with compliance requirements.
8. Use AWS-native security services (GuardDuty, Inspector, Macie, Config, WAF/Shield) to strengthen detection and assessment capabilities.
9. Adopt a multi-account strategy (e.g., AWS Organizations) to isolate environments and enforce policies.
10. Regularly review the AWS Shared Responsibility Model in light of new services and organizational changes.

Common Pitfalls and How to Avoid Them

• Assuming AWS handles data governance end-to-end — always implement your own data protection and classification standards.
• Underestimating the importance of identity management — ensure roles, permissions, and MFA are consistently applied.
• Overlooking monitoring and log retention — enable and centralize logs for auditing and forensics.
• Neglecting to validate configurations after service changes — automate configuration checks and continuous compliance tests.
• Misaligning service choices with security needs — choose IaaS, PaaS, or SaaS based on security responsibilities and risk tolerance.

Conclusion

The AWS Shared Responsibility Model is a practical compass for cloud security and compliance. By clearly distinguishing what AWS protects and what you must protect, organizations can design stronger architectures, implement disciplined governance, and reduce risk across cloud ecosystems. When teams understand the model and apply it consistently across services, workloads become more secure, auditable, and adaptable to evolving requirements.