What is the AWS shared responsibility model for security?

 

Quick Insight

When you move workloads into AWS, you don’t outsource accountability. AWS secures the infrastructure, but you own the data, applications, and configurations. The Shared Responsibility Model makes this distinction clear. Understanding it is essential because it sets the boundaries between what AWS guarantees and what your enterprise must control.

Why This Matters

Executives sometimes assume that “moving to AWS” means security is fully handled. That’s a dangerous misconception. If a breach occurs because an S3 bucket was left public or an IAM policy was too broad, that’s not AWS’s failure—it’s yours. Regulators, boards, and customers hold enterprises accountable for protecting data, regardless of where it lives. The Shared Responsibility Model ensures clarity: AWS provides the secure foundation, but you are responsible for how it’s used.

Here’s How We Think Through This

  1. AWS’s Responsibilities

    • Physical security of data centers.

    • Core cloud infrastructure: compute, storage, and networking.

    • Underlying software and hardware patching.

    • Ensuring the platform itself meets global compliance standards.

  2. Your Responsibilities

    • Data protection: Encrypt data at rest and in transit.

    • Identity and access: Apply least privilege, enforce MFA, and monitor accounts.

    • Configuration management: Secure S3 buckets, VPCs, and IAM policies.

    • Application security: Harden code, manage dependencies, and scan for vulnerabilities.

    • Monitoring & response: Detect threats, review logs, and remediate incidents.

  3. Shared Areas

    • Patching guest operating systems on EC2.

    • Securing network configurations (firewalls, ACLs, security groups).

    • Compliance reporting—AWS provides certifications, but you must align your use cases.

What Is Often Seen in Cybersecurity

In practice, we often see organizations:

  • Assuming AWS handles everything, leading to exposed S3 buckets or over-permissive IAM policies.

  • Neglecting monitoring, with CloudTrail enabled but no one reviewing logs.

  • Failing audits, because compliance reports are available in AWS Artifact but never mapped to enterprise policies.

  • Overlooking patching on EC2 instances, assuming AWS takes care of OS-level updates when it does not.

The enterprises that succeed use the Shared Responsibility Model as a governance framework. They align roles, policies, and metrics so that everyone understands which side of the line they’re accountable for.

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