10 Cloud computing has transformed how organizations deploy infrastructure, manage data, and deliver applications. As businesses adopt public, private, and hybrid cloud environments, a common question arises: what is the shared responsibility model? The shared responsibility model defines how security and compliance responsibilities are divided between a cloud service provider (CSP) and the customer. It clarifies who is responsible for protecting infrastructure, platforms, applications, and data in cloud environments. Understanding this model is essential for IT leaders, security teams, compliance officers, and storage architects. Misunderstanding it can lead to data breaches, regulatory violations, and operational risk. This article explains what the shared responsibility model is, how it works across service types (IaaS, PaaS, SaaS), and what it means for organizations managing modern cloud and hybrid environments. What is the shared responsibility model? The shared responsibility model is a cloud security framework that divides responsibilities between: The cloud provider, responsible for securing the underlying cloud infrastructure. The customer, responsible for securing their data, applications, access controls, and configurations. In simple terms: The provider secures the cloud. The customer secures what they put in the cloud. The exact division of responsibility depends on the cloud service model being used — Infrastructure as a Service (IaaS), Platform as a Service (PaaS), or Software as a Service (SaaS). Why the shared responsibility model matters Traditional on-premises environments place nearly all security responsibilities on the organization. In the cloud, some of those responsibilities shift to the provider. However, not all of them. Confusion often arises when organizations assume that moving workloads to the cloud means the provider handles all security concerns. That is not the case. Misconfigurations, weak identity policies, unsecured data, and improper access controls remain the customer’s responsibility. Many cloud security incidents stem from gaps in understanding the shared responsibility model rather than failures of cloud infrastructure itself. A clear understanding of what the shared responsibility model is helps organizations: Reduce security risk Maintain compliance Protect sensitive data Align security strategy with cloud architecture Avoid incorrect assumptions about provider coverage Security of the cloud vs. security in the cloud To fully understand what the shared responsibility model is, it helps to distinguish two core concepts: Security of the cloud (provider responsibility) Cloud providers are responsible for securing: Physical data centers Hardware and networking infrastructure Hypervisors and virtualization layers Core cloud services This includes physical security, power, cooling, hardware maintenance, and the foundational software that runs cloud services. Security in the cloud (customer responsibility) Customers are responsible for: Data protection Identity and access management (IAM) Application security Network configuration Encryption configuration Compliance management Backup and recovery policies Even when providers offer security tools, the customer must configure and manage them correctly. How the shared responsibility model differs by service type The shared responsibility model shifts depending on the type of cloud service being consumed. 1. Infrastructure as a Service (IaaS) In IaaS environments, the provider delivers virtualized infrastructure such as compute, storage, and networking. Provider responsibilities: Physical data centers Networking infrastructure Storage hardware Virtualization layer Customer responsibilities: Operating systems Applications Runtime environments Data Access control Encryption configuration Firewall settings IaaS offers flexibility but requires customers to manage more components. The security boundary sits lower in the stack. 2. Platform as a Service (PaaS) In PaaS environments, the provider manages the infrastructure and platform components, including operating systems and runtime environments. Provider responsibilities: Infrastructure Operating systems Middleware Runtime Customer responsibilities: Applications Data Identity management Access control Configuration settings With PaaS, customers manage fewer components than IaaS, but they remain responsible for securing application logic and data. 3. Software as a Service (SaaS) In SaaS environments, the provider delivers fully managed applications. Provider responsibilities: Infrastructure Platform Application management Updates and patches Customer responsibilities: Data governance User access control Account management Data sharing policies Regulatory compliance Even though the provider manages most of the stack, customers still control how data is used, accessed, and shared. What is the shared responsibility model in hybrid and multi-cloud environments? Most organizations operate in hybrid or multi-cloud environments. This adds complexity to the shared responsibility model. Each cloud provider may define responsibilities slightly differently. In hybrid environments, organizations must also account for: On-premises infrastructure Private cloud systems Edge environments Colocation facilities The responsibility boundary shifts depending on workload location. In multi-cloud architectures, security teams must understand the shared responsibility model for each provider and maintain consistent policies across environments. Governance frameworks must align controls across platforms to reduce risk. Common misconceptions about the shared responsibility model Misconception 1: “The cloud provider handles all security.” Cloud providers secure infrastructure. Customers must secure configurations, access controls, and data. Misconception 2: “Compliance is the provider’s responsibility.” Providers may offer compliance certifications, but customers are responsible for ensuring their workloads meet regulatory requirements such as GDPR, HIPAA, or industry-specific standards. Misconception 3: “If data is encrypted by default, we are fully protected.” Encryption features exist, but customers must manage keys, access policies, and lifecycle controls properly. Misconception 4: “Backups are automatic.” Many cloud services provide durability, but backup strategy, retention policies, and disaster recovery planning remain customer responsibilities. Key areas of customer responsibility To fully understand what the shared responsibility model is, organizations should focus on the primary areas where they retain responsibility: 1. Identity and access management (IAM) Role-based access control Multi-factor authentication Least privilege policies Credential lifecycle management IAM misconfigurations are a leading cause of cloud breaches. 2. Data protection Encryption at rest and in transit Key management Data classification Retention and deletion policies Data governance remains entirely within the customer domain. 3. Configuration management Network segmentation Firewall rules Storage access policies Logging and monitoring settings Cloud services are secure when configured properly. Misconfiguration introduces risk. 4. Backup and disaster recovery High availability does not replace backup strategy. Customers must define: Recovery time objectives (RTO) Recovery point objectives (RPO) Cross-region replication Offline or immutable backups 5. Monitoring and incident response Threat detection Audit logging Alerting Incident response workflows Cloud-native monitoring tools help, but customers must actively use them. How the shared responsibility model supports compliance Compliance frameworks often require documented controls for: Access management Data retention Audit logging Encryption Change management Cloud providers supply compliant infrastructure. Customers must implement compliant configurations. Auditors typically assess how organizations fulfill their portion of the shared responsibility model. Clear documentation of responsibilities reduces audit friction and regulatory risk. Evolving considerations: cloud storage and cyber resilience As data volumes grow, storage environments become central to the shared responsibility model. Customers must ensure: Object storage access policies are tightly controlled Buckets are not publicly exposed unless intended Versioning and immutability are configured correctly Ransomware protection strategies are in place Modern cloud architectures increasingly rely on object storage across hybrid environments. Security policies must extend consistently across public and private storage systems. Cyber resilience strategies — including immutable storage, air-gapped backups, and secure replication — fall within customer responsibility, even when the storage infrastructure itself is provider-managed. Best practices for managing shared responsibility Organizations can reduce risk by adopting structured approaches: 1. Map responsibilities clearly Document which team owns which layer of the stack. Align internal teams (security, DevOps, infrastructure) around responsibility boundaries. 2. Implement infrastructure as code (IaC) Codifying configurations reduces drift and minimizes human error. 3. Enforce least privilege access Regularly audit permissions. Remove unnecessary access. 4. Automate compliance checks Use cloud-native and third-party tools to continuously monitor configuration posture. 5. Educate teams Ensure that development, security, and operations teams understand what the shared responsibility model is and how it applies to their environment. Summary: what is the shared responsibility model? The shared responsibility model is a framework that defines how security and operational responsibilities are divided between a cloud provider and the customer. The provider secures the infrastructure. The customer secures their data, applications, identities, and configurations. The exact division depends on whether the organization is using IaaS, PaaS, or SaaS. In hybrid and multi-cloud environments, responsibilities multiply and require careful governance. A strong understanding of the shared responsibility model helps organizations reduce risk, maintain compliance, and build resilient cloud architectures. Cloud adoption does not eliminate security responsibilities. It changes them. Clear ownership, consistent policy enforcement, and proactive governance ensure that organizations manage their portion of responsibility effectively across modern cloud environments.
