AWS Organizations SCPs Now Support Full IAM Language

08/10/2025

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AWS Organizations SCPs Now Support Full IAM Language

A Game-Changer for AWS Security: SCPs Get a Major IAM Upgrade

Managing permissions across a large AWS Organization can be a complex undertaking. For years, Service Control Policies (SCPs) have served as the primary tool for setting broad security guardrails, but they came with significant limitations. Today, that has fundamentally changed. AWS has updated SCPs to support the full feature set of the IAM policy language, unlocking a new level of granular control and clarity for cloud governance.

This is more than a minor update; it’s a complete overhaul of how you can enforce security and compliance at scale. Let’s explore what this means for your AWS security posture.

The Old Way: Navigating SCP Limitations

Previously, SCPs used a simplified, restrictive version of the IAM policy syntax. While effective for broad strokes, they lacked the precision needed for many modern security scenarios.

The most significant challenge was the absence of an explicit Deny statement. To prevent an action, administrators had to construct complex Allow policies that used NotAction or NotResource. This often resulted in policies that were difficult to read, hard to maintain, and prone to misconfiguration. The lack of Condition elements also meant you couldn’t create nuanced rules based on context like IP addresses, required tags, or specific regions.

The New Era: Full IAM Power in Your SCPs

With this landmark update, SCPs are now on par with standard IAM policies, giving you access to the complete toolkit for defining permissions.

Here are the most impactful changes:

Explicit Deny Statements: You can now use a direct Deny statement in your SCPs. This is the most intuitive and secure way to block specific actions or services across your organization. A clear Deny is always easier to understand and audit than a convoluted Allow with multiple exceptions.
Powerful Condition Elements: This is perhaps the biggest win for security teams. You can now use Condition keys to create highly specific rules. For example, you can now enforce policies that:
- Restrict actions to specific AWS Regions (e.g., aws:RequestedRegion).
- Require specific tags on newly created resources (e.g., aws:RequestTag/CostCenter).
- Prevent the use of certain EC2 instance types (e.g., ec2:InstanceType).
- Limit access based on the principal’s tags (e.g., aws:PrincipalTag).
Granular Resource Specifications: While SCPs don’t grant permissions, they do set the maximum boundary. The ability to use more detailed Resource elements in Deny statements allows you to create more targeted restrictions without affecting unrelated resources.
Multiple Policy Statements: You are no longer limited to a single statement. You can now combine multiple Allow and Deny statements within a single, well-structured SCP, making your policies more organized and readable.

Why This Is a Game-Changer for Cloud Governance

This update transforms SCPs from blunt instruments into precision tools, offering substantial benefits for security, operations, and compliance.

Unprecedented Granularity and Control: The ability to use Condition keys allows you to implement security controls that were previously impossible at the organizational level. Enforcing regional compliance or mandating a tagging strategy is now straightforward.
Improved Clarity and Maintainability: Policies using explicit Deny statements are vastly easier to read, write, and audit. This reduces the risk of human error and simplifies the process of demonstrating compliance.
Consistent Policy Management: By aligning SCP syntax with IAM policy syntax, AWS has flattened the learning curve. Your team can now apply their existing IAM knowledge directly to organizational guardrails, promoting consistency and reducing training overhead.
Simplified Compliance Enforcement: Need to ensure no resources are deployed outside of approved regions? Or that every S3 bucket has encryption enabled? You can now build these non-negotiable rules directly into your SCPs, ensuring that no account in your organization can bypass them.

Actionable Security Tips: Putting the New SCPs to Work

To start leveraging these powerful new features, consider implementing the following security guardrails:

Audit and Refactor Your Existing SCPs: Review your current policies. Many complex Allow statements with NotAction can likely be rewritten as simple, clear Deny statements.

Enforce Regional Controls: If your business operates only in specific AWS Regions, you can create a powerful SCP to deny all actions outside of them. This is a critical step in preventing accidental deployments and reducing your attack surface.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "DenyActionsOutsideApprovedRegions",
      "Effect": "Deny",
      "NotAction": "iam:*",
      "Resource": "*",
      "Condition": {
        "StringNotEquals": {
          "aws:RequestedRegion": ["us-east-1", "eu-west-2"]
        }
      }
    }
  ]
}

Mandate Resource Tagging: Enforce good governance by denying the creation of key resources (like EC2 instances or S3 buckets) if they don’t include a specific tag, such as CostCenter or Project.
Restrict High-Risk or High-Cost Services: Explicitly deny the use of large, expensive EC2 instance types or block access to entire services that are not approved for use within your organization.

This evolution of Service Control Policies marks a significant step forward for AWS security. By embracing the full power of the IAM policy language, you can build a more secure, compliant, and well-governed cloud environment. Now is the time to review your organizational policies and start implementing these more powerful and precise controls.

Source: https://aws.amazon.com/blogs/security/unlock-new-possibilities-aws-organizations-service-control-policy-now-supports-full-iam-language/