About the shared accounts
Three special AWS accounts are associated with AWS Control Tower; the management account, the audit account, and the log archive account. These accounts usually are referred to as shared accounts, or sometimes as core accounts.
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You can select customized names for the audit and log archive accounts when you're setting up your landing zone. For information about changing an account name, see Externally changing AWS Control Tower resource names.
You also can specify an existing AWS account as an AWS Control Tower security or logging account, during the initial landing zone setup process. This option eliminates the need for AWS Control Tower to create new, shared accounts. (This is a one-time selection.)
For more information about the shared accounts and their associated resources, see Resources created in the shared accounts.
Management account
This AWS account launches AWS Control Tower. By default, the root user for this account and the IAM user or IAM administrator user for this account have full access to all resources within your landing zone.
Note
As a best practice, we recommend signing in as an IAM Identity Center user with Administrator privileges when performing administrative functions within the AWS Control Tower console, instead of the signing in as the root user or IAM administrator user for this account.
For more information about the roles and resources available in the management account, see Resources created in the shared accounts.
Log archive account
The log archive shared account is set up automatically when you create your landing zone, if you do not specifically bring another AWS account.
This account contains a central Amazon S3 bucket for storing a copy of all AWS CloudTrail and AWS Config log files for all other accounts in your landing zone. As a best practice, we recommend restricting log archive account access to teams responsible for compliance and investigations, and their related security or audit tools. This account can be used for automated security audits, or to host custom AWS Config Rules, such as Lambda functions, to perform remediation actions.
Amazon S3 bucket policy
For AWS Control Tower landing zone version 3.3 and later, accounts must meet an
aws:SourceOrgID condition for any write permissions to your
Audit bucket. This condition ensures that CloudTrail only can write logs on behalf of
accounts within your organization to your S3 bucket; it prevents CloudTrail logs
outside your organization from writing to your AWS Control Tower S3 bucket. For more
information, see AWS Control Tower landing zone version 3.3.
For more information about the roles and resources available in the log archive account, see Log archive account resources
Note
These logs cannot be changed. All logs are stored for the purposes of audit and compliance investigations related to account activity.
Audit account
This shared account is set up automatically when you create your landing zone, if you do not specifically bring another account.
The audit account should be restricted to security and compliance teams with auditor (read-only) and administrator (full-access) cross-account roles to all accounts in the landing zone. These roles are intended to be used by security and compliance teams to:
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Perform audits through AWS mechanisms, such as hosting custom AWS Config rule Lambda functions.
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Perform automated security operations, such as remediation actions.
The audit account also receives notifications through the Amazon Simple Notification Service (Amazon SNS) service. Three categories of notification can be received:
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All Configuration Events – This topic aggregates all CloudTrail and AWS Config notifications from all accounts in your landing zone.
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Aggregate Security Notifications – This topic aggregates all security notifications from specific CloudWatch events, AWS Config Rules compliance status change events, and GuardDuty findings.
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Drift Notifications – This topic aggregates all the drift warnings discovered across all accounts, users, OUs, and SCPs in your landing zone. For more information on drift, see Detect and resolve drift in AWS Control Tower.
Audit notifications that are triggered within a member account also can send alerts to a local Amazon SNS topic. This functionality allows account administrators to subscribe to audit notifications that are specific to an individual member account. As a result, administrators can resolve issues that affect an individual account, while still aggregating all account notifications to your centralized audit account. For more information, see Amazon Simple Notification Service Developer Guide.
For more information about the roles and resources available in the audit account, see Audit account resources.
For more information about programmatic auditing, see Programmatic roles and trust relationships for the AWS Control Tower audit account.
Important
The email address you provide for the audit account receives AWS Notification - Subscription Confirmation emails from every AWS Region supported by AWS Control Tower. To receive compliance emails in your audit account, you must choose the Confirm subscription link within each email from each AWS Region supported by AWS Control Tower.
