Cloud Security Basics: Understanding the Shared Responsibility Model for AWS, Azure, and GCP

As organizations migrate critical systems to the cloud, security expectations have fundamentally shifted. One of the most misunderstood yet essential concepts in cloud security is the Shared Responsibility Model.

Whether your infrastructure runs on AWS, Microsoft Azure, or Google Cloud Platform (GCP), security is never fully outsourced. Cloud providers deliver secure platforms, but customers remain accountable for how those platforms are configured, accessed, and operated.

Misunderstanding this division of responsibilities is a leading cause of cloud security gaps, audit findings, and compliance failures.

What Is the Shared Responsibility Model?

The Shared Responsibility Model defines how security responsibilities are divided between the cloud provider and the customer.

Cloud providers are responsible for security of the cloud protecting the infrastructure that runs the cloud itself. Customers are responsible for security in the cloud securing what they deploy and manage within that infrastructure.

Although AWS, Azure, and GCP use slightly different terminology, the underlying principle remains consistent across all major providers. This distinction becomes especially critical during audits, where assumptions about control ownership often break down.

What Cloud Providers Secure: "Security of the Cloud"

Cloud providers focus on securing the platform foundation:

• Physical infrastructure — Data centers, server hardware, and networking equipment
• Environmental controls — Power, cooling, fire suppression, and physical access security
• Platform foundation — Hypervisor layers, core networking, and managed service infrastructure
• Compliance certifications — SOC 2, ISO 27001, FedRAMP attestations for their infrastructure

These controls are continuously monitored and independently audited, forming the baseline security foundation all customers inherit.

What Customers Are Responsible For: "Security in the Cloud"

Everything configured and operated inside the cloud environment remains the customer's responsibility. This is where most security and compliance gaps occur.

Customer responsibilities include:

• Identity and access management — User accounts, roles, permissions, and multi-factor authentication
• Network configuration — Security groups, firewall rules, VPC design, and segmentation
• Application security — Code vulnerabilities, runtime protection, and secure development
• Data protection — Encryption at rest and in transit, key management, and classification
• Logging and monitoring — Security event detection, log retention, and incident response
• Patch management — Operating system and application updates (for IaaS workloads)
• Compliance evidence — Demonstrating controls are implemented and operating effectively

Even with fully managed services, customers must ensure secure configuration and regulatory compliance.

How Responsibility Shifts Across Service Models

The shared responsibility model operates on a spectrum:

Infrastructure as a Service (IaaS) — Customers have maximum responsibility, including operating systems, applications, and network configurations.

Platform as a Service (PaaS) — Providers handle infrastructure (like OS patching), but customers control access policies, data encryption, and application security.

Software as a Service (SaaS) — Providers manage nearly everything, but customers remain responsible for identity governance, access control, and data classification.

Key principle: As you move toward managed services, providers assume more infrastructure responsibilities—but customer accountability for data, access, and compliance never disappears.

Why This Matters for Compliance

During SOC 2, ISO 27001, HIPAA, or other assessments, organizations must demonstrate that:

• Cloud access is properly controlled and regularly reviewed
• Systems are configured according to security baselines
• Sensitive data is encrypted and protected
• Security controls operate continuously, not just during audits
• Configuration changes are logged and monitored

Simply inheriting a cloud provider's certifications is insufficient. You must provide independent evidence that your portion of shared responsibility is actively managed.

The Scaling Challenge: Why Manual Approaches Break Down

As cloud environments grow, they become exponentially harder to govern. Multiple accounts, regions, and teams introduce complexity that static documentation cannot manage.

Common challenges:

• Fragmented ownership — Different teams with inconsistent security practices
• Configuration drift — Security settings change without detection
• Scattered evidence — Audit artifacts across multiple tools and repositories
• Manual monitoring — Point-in-time reviews miss issues between audits

These gaps increase operational risk and audit pressure as organizations scale.

Operationalizing Shared Responsibility with Continuous Compliance

Effective management requires more than annual reviews. Organizations need real-time visibility and the ability to detect and remediate issues as they arise.

Continuous compliance enables teams to:

• Monitor cloud configurations in real time
• Automatically collect audit evidence
• Identify drift and gaps early
• Maintain year-round audit readiness

This approach aligns cloud security governance with the pace of modern cloud operations.

How Quantarra Brings Clarity to Cloud Accountability

Quantarra helps organizations translate shared responsibility into clearly defined, measurable, and auditable controls.

The platform provides:

• Multi-cloud visibility — Unified monitoring across AWS, Azure, and GCP
• Framework mapping — Automatic alignment to SOC 2, ISO 27001, HIPAA, and NIST CSF 
• Continuous evidence collection — Real-time documentation of control effectiveness
• Risk-based prioritization — Focus on gaps posing the greatest compliance risk

By centralizing visibility and automating evidence collection, Quantarra reduces ambiguity around cloud accountability and supports continuous audit readiness as environments evolve.

Conclusion: Shared Responsibility Requires Shared Understanding

Cloud providers deliver secure infrastructure, but security outcomes depend on how organizations configure and use it.

Understanding the Shared Responsibility Model is essential for secure cloud adoption at scale, meeting regulatory obligations, passing audits with confidence, and building customer trust.

Organizations that treat cloud security as a continuous process—not a one-time setup—are better positioned to scale confidently and remain audit-ready throughout the year.

Want to Strengthen Cloud Security Without Adding Complexity?

Discover how continuous compliance platforms help teams manage cloud responsibility with clarity and confidence across AWS, Azure, and GCP.

Learn more: quantarra.io