What is AWS Organizations SCP, and how does it enhance control over accounts?

AWS Organizations Service Control Policies (SCPs) are a feature within AWS Organizations, which is a service that allows you to centrally manage and govern multiple AWS accounts. SCPs are a critical component of AWS Organizations and play a key role in enhancing control and security over AWS accounts within an organization. Here's how AWS Organizations SCPs work and how they enhance control:

1. Centralized Policy Management:

   • SCPs allow you to create and apply fine-grained policies at the organization level. These policies are centrally managed and define the guardrails for what actions can be performed within member accounts.

2. Hierarchy of Accounts:

   • In AWS Organizations, accounts are organized into an organizational hierarchy. You can have a root account, which is the top-level account, and multiple organizational units (OUs) that group accounts together.

3. Inheritance of Policies:

   • SCPs can be attached to the root of the organization or individual OUs. Policies attached at the root apply to all accounts within the organization. When you attach an SCP to an OU, it affects all the accounts within that OU and any nested OUs, allowing for fine-grained control.

4. Permission Boundaries:

   • SCPs act as permission boundaries, explicitly allowing or denying access to AWS services and actions. They are used to complement IAM policies and provide an additional layer of control.

5. Deny Overrides Allow:

   • SCPs have an "explicit deny" rule, which means that if an SCP denies access to a particular action, it takes precedence over any "allow" policies attached to an IAM entity (e.g., user or role).

6. Policy Syntax:

   • SCPs are defined using a simple JSON policy syntax. You can explicitly specify which AWS services and actions are allowed or denied. This level of granularity allows you to tailor policies to your organization's specific needs.

7. Prevent Unauthorized Actions:

   • SCPs are particularly useful for preventing unauthorized or accidental actions. For example, you can create an SCP that restricts accounts from creating publicly accessible S3 buckets or launching specific EC2 instance types.

8. Security and Compliance:

   • SCPs help organizations enforce security and compliance standards consistently across all member accounts. They are valuable for industries with regulatory requirements.

9. Dynamic and Evolving Control:

   • SCPs can be updated and refined as your organization's requirements change. This flexibility allows you to adapt to new services and features while maintaining control.

10. Audit and Visibility:

    • AWS Organizations provides audit and visibility features to track and understand how SCPs are affecting access and actions within your organization.

AWS Organizations SCPs are a critical tool for organizations with multiple AWS accounts. They enable centralized policy management, fine-grained control, and the enforcement of security and compliance standards across your AWS environment. By using SCPs in combination with IAM policies, you can implement a robust security and access control strategy for your organization's accounts.