AWS Control Tower: Mastering Multi-Account Security, Compliance, and Governance at Scale
AWS Control Tower provides organizations with a centralized governance layer that enables them to implement security best practices, operational controls, and compliance requirements at scale.
Published Mar 18, 2025
Securing, conforming, and managing multiple AWS accounts is akin to traveling on a highway with no traffic rules—without an organized strategy, organizations will be exposed to misconfigurations, security compromises, and regulatory non-compliance. As organizations grow their AWS footprint, they are likely to struggle with inconsistent security policies, isolated monitoring, and operational drudgery of dealing with a multitude of accounts.
AWS Control Tower solves for this by providing organizations with a centralized governance layer that enables them to implement security best practices, operational controls, and compliance requirements at scale. With its guardrails pre-configured, self-enforcing governance rules, and effortless multi-account management, Control Tower simplifies cloud security with reduced operational complexity.
This blog provides an in-depth overview of how AWS Control Tower enforces governance using Detective, Proactive, and Preventive Controls. It also explains real-world use cases and step-by-step implementation plans to help organizations secure their cloud environments effectively.
AWS Control Tower leverages an extensive collection of security and compliance rules known as Controls Library to construct a governance structure for AWS Organizations. Controls allow a system based on policies to manage security in a way that all the accounts within an AWS Organization meet industry best practices and regulatory requirements.
AWS Control Tower Controls Library falls into three broad categories:
- Detective Controls – Detect and alarm on security activity and compliance infringements.
- Proactive Controls – Authenticate security compliance prior to deploying resources.
- Preventive Controls – Impose security constraints to prevent unauthorized usage.
All of the above controls collectively provide ongoing compliance, operational security, and risk management among AWS accounts.
Once the Control Tower Landing Zone is turned on, all controls are controlled from the AWS Control Tower dashboard. Organizations are able to filter and customize controls by:
- Compliance Frameworks – CIS, NIST, PCI DSS, etc.
- Service Type – IAM, S3, EC2, VPC, etc.
- Control Type – Detective, Preventive, or Proactive.
AWS Control Tower allows companies to switch on governance controls at the Organizational Unit (OU) level. This means that all accounts within an OU inherit and use the selected controls by default.
Steps to turn on a control:
- Navigate to the Control Tower dashboard → Select "Controls."
- Use the filters to find the target control (e.g., service type or compliance framework).
- Click on Enable Control → Choose the Organizational Unit (OU).
- The selected control is enforced across on all accounts in the OU.
After you enable the controls, it will ensure that all resources and services in the accounts comply with organizational policies.
Detective Controls continuously scan AWS environments in real-time for security misconfiguration, policy violations, and anomalous behavior. Detective Controls provide real-time security intelligence to alert security teams of incidents to investigate, risk assessments to conduct, and corrective action to take.
The primary detective control mechanisms are:
- AWS Config – Tracks resource configurations and detects compliance issues.
- AWS CloudTrail – Logs API calls into a cloud-based, centralized vault for forensic analysis and security audits.
- Amazon GuardDuty – Leverages machine learning to detect unauthorized access attempts.
Use Case: AWS Config was utilized by an international fintech company to detect unauthorized security group update. The service notified on a misconfigured firewall rule that exposed an EC2 instance to the public internet, excluding the ability to carry out a data breach before exploitation.
In order to successfully implement detective controls:
- Enable AWS Config for continuous resource configuration tracking.
- Implement AWS Config Rules to detect non-compliant configurations.
- Enable CloudTrail Logging to record AWS API calls for forensic analysis.
- Use GuardDuty to detect unusual behavior and trigger security alerts.
- Leverage AWS Security Hub to consolidate security findings per account.
Detective controls offer visibility into security risk, so teams can react prior to threats escalating.
Proactive Controls make AWS resources conform to security policies before deployment, and misconfigurations never reach production. They are enforced by AWS CloudFormation Hooks and Service Control Policies (SCPs).
Use Case: A bank utilized AWS CloudFormation Hooks to enforce encryption for all S3 buckets before deployment to achieve PCI DSS compliance.
- Make CloudFormation Hooks enabled to validate infrastructure-as-code before deployment.
- Implement SCPs on the OU level to enforce security policies across AWS accounts.
- Proactive controls are tested on an item-by-item basis prior to deploying them organization-wide.
- Periodically update policies with current security trends and changes in compliance.
Proactive controls create a first line of defense, preventing security gaps from taking place.
Preventive Controls stop security attacks and policy violations from occurring in the first place. Preventive Controls stop non-compliant activity across AWS accounts.
Key Preventive Control services include:
- Service Control Policies (SCPs) – Stop AWS actions at the organization(OU) level.
- IAM Permission Boundaries – Limit the permissions given to IAM roles.
- AWS Organizations Policies – Enforce organization-wide security policies.
Use Case: A health care professional used SCPs to avoid the creation of public S3 buckets for HIPAA compliance.
- Define SCPs based on security policies and compliance needs.
- Implement SCPs hierarchically at the OU level for a centralized policy framework.
- Test SCPs before rolling them out more broadly to prevent any unintended access problems.
- Monitor policy effectiveness and adjust with evolving security requirements.
Preventive controls are an automated security layer, and AWS environments are compliant without the need for human interaction.
AWS Control Tower is a core governance offering that enables organizations to manage security, compliance, and operational policies for AWS accounts in a unified way.
Key Takeaways:
- Detective Controls provide security monitoring in real-time.
- Proactive Controls make it a point to prevent misconfigurations before deploying them.
- Preventive Controls enforce security policies and block unauthorized activity.
What’s next? Start by enabling AWS Control Tower and enforcing custom security controls appropriate for your organization.
Clement Pakkam Isaac is a Specialist Senior at Deloitte Consulting and an accomplished AWS Ambassador with 15 AWS certifications. As a recognized thought leader in cloud computing, Clement actively contributes to the AWS community by sharing insights, best practices, and innovations in cloud infrastructure, automation, and modernization.
With over 13 years of experience in technical consulting and leadership, Clement has architected and delivered large-scale cloud solutions for higher education and consumer industries. His expertise spans automation, infrastructure as code, resilience, observability, security, risk management, migration, modernization, and digital transformation.
As an AWS Ambassador, Clement plays a pivotal role in advancing cloud adoption by engaging with the broader cloud community through technical blogs, speaking engagements, and mentorship. His influence extends to guiding organizations in adopting cutting-edge AWS services, driving innovation through scalable and secure cloud solutions, and helping businesses achieve operational excellence in their cloud transformation journeys.