Securing a rapidly expanding AWS environment requires more than just IAM users, roles, and policies. As teams, accounts, and workloads grow, a more foundational approach is necessary — a means to centrally govern, restrict, and secure all resources across accounts.
That “hidden backbone” is AWS Organizations.
In this guide, we clarify how AWS Organizations integrates with IAM, SCPs, ABAC, managed policies, and resource policies, providing practical examples that you can apply in real environments.
🚀 Features for AWS Organizations:
AWS Organizations does more than just create multiple AWS accounts. It serves as the control plane for:
- Manage your AWS accounts
- Define and manage your organization
- Secure and monitor your accounts
- Control access and permissions
- Share resources across accounts
- Audit your environment for compliance
- Centrally manage billing and costs
🚀 Use cases for AWS Organizations:
Automate the creation of AWS accounts and categorize workloads
You can automate the creation of AWS accounts to quickly launch new workloads. Add the accounts to user-defined groups for instant security policy application, touchless infrastructure deployments, and auditing.
Define and enforce audit and compliance policies
You can implement service control policies (SCPs) to ensure that your users engage only in actions that align with your security and compliance requirements.
Provide tools and access for your Security teams while encouraging development
Create a security group with read-only access to all resources.
Share common resources across accounts
Organizations makes it easy for you to share critical central resources across your accounts.
It is the foundation of an enterprise-grade AWS security model.
1. How AWS Organizations Works With IAM
AWS Organizations and IAM are often misunderstood. Here’s the simplest mental model:
IAM = What a principal can do inside an account
(Users, roles, groups)
SCP = What is allowed at the organizational level
(Sets the boundary of maximum permissions)
Example of the interaction
IAM says: “You can delete S3 buckets.”
SCP says: “No one is allowed to delete S3 buckets.”
Final result: Bucket deletion is denied.
SCPs never grant access — they only restrict access.
2. Managing Access Permissions in an Organization
AWS Organizations provides multiple tools for governing security.
a) Service Control Policies (SCPs)
SCPs apply at:
- the root organization
- OU (Organizational Unit)
- individual accounts
They define maximum permissions, regardless of IAM.
Useful for enforcing:
- mandatory encryption
- mandatory logging
- region restrictions
- disallowing IAM user creation
- preventing CloudTrail deletion
- protecting guardrails
b) IAM Roles for Cross-Account Access
Instead of creating admin users in each account, you create one central IAM role per use case.
Examples:
- SecurityAuditRole for the security team
- AutomationRole for CI/CD pipelines
- BillingRole for finance
- Roles are assumed cross-account using the AWS CLI or AWS SSO.
c) IAM Identity Center (AWS SSO)
The recommended identity solution.
It provides:
- Centralized users and groups
- MFA enforced everywhere
- Fine-grained permission sets
- Automatic access provisioning per account
This eliminates IAM users entirely.
3. AWS Managed Policies
AWS provides prebuilt policies so you don’t reinvent the wheel.
Common managed policies:
- SecurityAudit → read-only security insights
- AdministratorAccess → full control (use carefully)
- ViewOnlyAccess → non-intrusive visibility
- AmazonS3FullAccess
- AWSLambdaExecute
Advantages
✔ Automatically updated by AWS
✔ Quick to apply
✔ Good starting point for least privilege
Caution
Many managed policies are too broad.
Prefer custom policies for production.
4. Attribute-Based Access Control (ABAC) with Tags
Attribute-based access control enables you to use tags attached to AWS resources and identities to manage access. For instance, a user can access a resource only if both share the same tag value.
Perfect for:
- multi-team platforms
- dynamic environments
- large-scale automation
5. Identity-Based IAM Policy
Identity policies attach to:
- IAM users
- IAM roles
- IAM groups
They grant permissions.
Identity policies = grant permissions
SCPs = restrict permissions
6. Resource-Based Policy
Resource policies protect resources like:
- S3 buckets
- KMS keys
- Lambda functions
- SQS queues
- API Gateway APIs
They allow access from:
- other AWS accounts
- specific IAM roles or services
- external integrations
🔥Final thoughts
AWS Organizations serves as the critical foundation for securing, managing, and scaling large AWS environments.
By integrating IAM, SCPs, resource policies, managed policies, and ABAC, you establish a comprehensive security model that is:
- Centralized
- Least-privilege by default
- Automated
- Compliant
- Enterprise-ready
Reference: AWS Documentation
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