AWS IAM Identity Center (successor to AWS Single Sign-On) provides account assignment APIs and AWS CloudFormation support to automate access across AWS Organizations accounts. With those available APIs, this solution allows all access provided via the IAM Identity Center services to be automated via API / CloudFormation templates, and managed as code converting all currently manual activities.

AWS IAM Identity Center requires the AWS Organizations service enabled in your AWS account.

• Use AWS CodeCommit to securely source control your own IAM Identity Center code repository. Utilize CodePipeline to create and update CloudFormation stacks of IAM Identity Center and other AWS services.
  • The AWS CodePipeline will first deploy CloudFormation stacks to create a security S3 bucket, automation Lambda functions and other AWS resources.
  • Once the CloudFormation stack is completed, CodePipeline syncs all the mapping files to a Secure S3 bucket
  • Pipeline invokes the Lambda to create IAM Identity Center resources by referring the JSON files in the s3 bucket.
  • Amazon EventBridge triggers email notifications via Amazon Simple Notification Service (SNS) on manual changes to Identity Center and invokes Amazon Lambda function to remove manual changes revert back to baseline configuration.
• This solution works with both Control Tower and non Control Tower based landing zones.

1. AWS Organizations and IAM Identity Center are enabled.
2. S3 Data event is enabled for IAM Identity Center source S3 bucket in account's CloudTrail service.
   • Because this solution uses AWS S3 Object-level API to trigger the lambda automation and those Data events are enabled by default. Additional charges apply

This solution can be implemented in Organization Management account or a delegated administrator (recommended) acount for Identity Center. It is recommended to delegate administrator for Identity Center to a separate member account dedicated for identity and access management to reduce exposure to management account and for better control over account access. Follow the appropriate instructions below depending on where you configure Identity Center, Organization Management account or a member account delegated as an administrator for Identity Center.

Important note if you have AWS Control Tower enabled If your AWS IAM Identity Center user account is disabled, you'll get an error message when trying to provision new accounts in Account Factory. You can re-enable your IAM Identity Center user in the IAM Identity Center console.

AWS Control Tower also offers preconfigured groups to organize users that perform specific tasks in your accounts. AWS Control Tower creates these groups and assigns pre-configured permission sets to these groups and provisions them in the Organization Management account. You can also view the list of groups and corresponding permission sets.

AWS Control Tower requires these permission sets to exist for account creation and provisioning purposes. To ensure that this solution does not de-provision or delete the Control Tower permission sets, you must tag AWS Control Tower created permission sets with "key:ManagedBy" and "value:ControlTower" before deploying the solution. Additionally, update the value of "ControlTowerEnabled" to "true" as mentioned in the implementation steps below.

1. Clone this repository. cd into the repository root directory.
2. Create an AWS CodeCommit repository.
   • The name of CodeCommit repository will be used when we create pipeline with codepipeline-stack.template.
3. In your AWS Organization Management account, use the codepipeline-stack.template cloudformation template to provision the AWS Code Pipeline and related CICD resources in the same region that IAM Identity Center service is enabled.
4. Specify parameter values in identity-center-stacks-parameters.json file in the repository. Those parameters will be used by the CodePipeline to create other 2 CloudFormation stacks.
   • The value of "ICMappingBucketName" parameter is used by both codepipeline-stack.template and identity-center-stacks-parameters.json.
   • As you've chosen to manage Identity Center in Organization Management account, the value of AdminDelegated must be false.
   • If you have Control Tower enabled, change the value of "ControlTowerEnabled" to "true", else, keep it "false".
   • If you have an existing IAM role or a user to manage Identity Center without triggering notifications for manual changes, add the ARN of the existing IAM role or user to "ICAutomationAdminArn" and change the value of "createICAdminRole" to "false". If you do not have an existing IAM role or a user, leave the value of "ICAutomationAdminArn" empty '' and change the value of "createICAdminRole" to true and the solution will create an IAM role for you.
   • If you have an existing IAM role or a user to administer KMS key used to encrypt S3 bucket for Identity Center solution, without triggering notifications for manual changes, add the ARN of the existing IAM role or user to "ICKMSAdminArn" and change the value of "createICKMSAdminRole" to "false". If you do not have an existing IAM role or a user, leave the value of "ICKMSAdminArn" empty '' and change the value of "createICKMSAdminRole" to true and the solution will create an IAM role for you.
5. Create your own permission sets json defination files as well as the account assignment defination file "global-mapping.json" and "target-mapping.json".
6. Push the following files to your CodeCommit repository, e.g. Linux tree structure:

.
├── LICENSE
├── README.md
├── diagram
│   └── architecture_diagram.jpg
├── src
│   ├── codebuild
│   │   ├── buildspec-mapping.yml
│   │   ├── buildspec-param.yml
│   │   └── buildspec-zipfiles.yml
│   └── lambda-code
│       ├── identity-center-auto-assign
│       │   ├── auto-assignment.py
│       │   └── cfnresponse.py
│       └── identity-center-auto-permissionsets
│           ├── auto-permissionsets.py
│           └── cfnresponse.py
├── identity-center-automation.template
├── codepipeline-stack.template
├── identity-center-s3-bucket.template
└── identity-center-stacks-parameters.json
└── identity-center-mapping-info
    ├── global-mapping.json
    └── target-mapping.json
    └── permission-sets
        ├── example-1.json
        └── example-2.json
        └── ...
        └── example-99.json

7. The pipeline will automatically create 2 new CloudFormation stacks IdentityCenter-S3-Bucket-Stack and IdentityCenter-Automation-Stack in your account and upload your permission sets and mapping files to a centralized S3 bucket. The non-default parameters are specified in identity-center-stacks-parameters.json file.
8. The 'ReviewAndExecute' stage needs manual approval before the Pipeline invoke the Lambda function. Once the pipeline is completed, verify the permission sets and account mapping on the AWS IAM Identity Center service console.

Delegated administration provides a convenient way for assigned users in a registered member account to perform most IAM Identity Center administrative tasks. When you enable IAM Identity Center, your IAM Identity Center instance is created in the management account in AWS Organizations by default. This was originally designed this way so that IAM Identity Center can provision, de-provision, and update roles across all your organization's member accounts. Even though your IAM Identity Center instance must always reside in the management account, you can choose to delegate administration of IAM Identity Center to a member account in AWS Organizations, thereby extending the ability to manage IAM Identity Center from outside the management account. For more details, visit https://docs.aws.amazon.com/singlesignon/latest/userguide/delegated-admin.html#delegated-admin-tasks-member-account

Enabling delegated administration provides the following benefits: - Minimizes the number of people who require access to the management account to help mitigate security concerns - Allows select administrators to assign users and groups to applications and to your organization's member accounts

Delegated administrator cannot manage permission sets provisioned in the management account This solution works around this by skipping the permission sets provisioned in the management account and storing a list of skipped permission sets in a DynamoDB table "IC-SkippedPermissionSets". This is also true for Control Tower based landing zones.

As delegated admin is not allowed to manage permission sets provisioned in management account or assign a permission set to the management account, you must manually create a permission set in the management account, to use just for the management account. For more details, view best practices for delegated administrator for Identity Center.

This also recommended as a best practice:

Create permission sets for use only in the management account – This makes it easier to administer permission sets tailored just for users accessing your management account and helps to differentiate them from permission sets managed by your delegated administrator account.

If you have already delegated an AWS account as administrator for Identity Center, follow the steps listed under Deployment in delegated administrator account section below. If you have not delegated an AWS account as administrator for Identity Center yet, perform the following steps to delegate a member account as an administrator for Identity Center:

1. Clone this repository. cd into the repository root directory.
2. In the Organization Management account, create a stack in AWS CloudFormation console at https://console.aws.amazon.com/cloudformation.
3. On the Specify stack details page, type a stack name in the Stack name box. You can choose any name, such as, delegate-IC-admin.
4. In the Parameters section, specify the following parameters:
   • delegate: true
   • accountid: 123456789012 (Account Id of the account you'd like to delegate as administrator)
5. Choose Next to proceed with setting options for your stack and create the stack.
6. Once the CloudFormation stack is created successfully, follow the steps under Deployment section below.

1. Create an AWS CodeCommit repository.
   • The name of CodeCommit repository will be used when we create pipeline with codepipeline-stack.template.
2. In your delegated administrator account, use the codepipeline-stack.template cloudformation template to provision the AWS Code Pipeline and related CICD resources in the same region that IAM Identity Center service is enabled.
3. Specify parameter values in identity-center-stacks-parameters.json file in the repository. Those parameters will be used by the CodePipeline to create other 2 CloudFormation stacks.
   • The value of "ICMappingBucketName" parameter is used by both codepipeline-stack.template and identity-center-stacks-parameters.json. Make sure to use the same S3 bucket name you specified in the codepipeline-stack.template parameters.
   • As you've chosen to manage Identity Center in a delegated administrator account, the value of "AdminDelegated" must be true.
   • If you have Control Tower enabled, change the value of "ControlTowerEnabled" to "true", else, keep it "false".
   • If you have an existing IAM role or a user to manage Identity Center without triggering notifications for manual changes, add the ARN of the existing IAM role or user to "ICAutomationAdminArn" and change the value of "createICAdminRole" to "false". If you do not have an existing IAM role or a user, leave the value of "ICAutomationAdminArn" empty '' and change the value of "createICAdminRole" to true and the solution will create an IAM role for you.
   • If you have an existing IAM role or a user to administer KMS key used to encrypt S3 bucket for Identity Center solution, without triggering notifications for manual changes, add the ARN of the existing IAM role or user to "ICKMSAdminArn" and change the value of "createICKMSAdminRole" to "false". If you do not have an existing IAM role or a user, leave the value of "ICKMSAdminArn" empty '' and change the value of "createICKMSAdminRole" to true and the solution will create an IAM role for you.
4. Create your own permission sets json defination files as well as the account assignment defination file "global-mapping.json" and "target-mapping.json".
5. Push the following files to your CodeCommit repository, e.g. Linux tree structure:

.
├── LICENSE
├── README.md
├── diagram
│   └── architecture_diagram.jpg
├── src
│   ├── codebuild
│   │   ├── buildspec-mapping.yml
│   │   ├── buildspec-param.yml
│   │   └── buildspec-zipfiles.yml
│   └── lambda-code
│       ├── identity-center-auto-assign
│       │   ├── auto-assignment.py
│       │   └── cfnresponse.py
│       └── identity-center-auto-permissionsets
│           ├── auto-permissionsets.py
│           └── cfnresponse.py
├── identity-center-automation.template
├── codepipeline-stack.template
├── identity-center-s3-bucket.template
└── identity-center-stacks-parameters.json
└── identity-center-mapping-info
    ├── global-mapping.json
    └── target-mapping.json
    └── permission-sets
        ├── example-1.json
        └── example-2.json
        └── ...
        └── example-99.json

6. The pipeline will automatically create 2 new CloudFormation stacks IdentityCenter-S3-Bucket-Stack and IdentityCenter-Automation-Stack in your account and upload your permission sets and mapping files to a centralized S3 bucket. The non-default parameters are specified in identity-center-stacks-parameters.json file.
7. The 'ReviewAndExecute' stage needs manual approval before the Pipeline invoke the Lambda function. Once the pipeline is completed, verify the permission sets and account mapping on the AWS IAM Identity Center service console.

Note: If you chose to create IAM role for Identity Center and KMS admin, the ARNs of those roles can be found in the output tab of the IdentityCenter-S3-Bucket-Stack in AWS CloudFormation console. To make manual changes to Identity Center without triggering notifications, you can assume the ICAdminRole role. View steps on how to assume a role.

• If any change had been made through another approach without updating JSON mapping files in the source, such as deleting a permission set, will this solution be able to detect and fix those drifts?

  • A: Yes. The automation will use the mapping definitions in the s3 bucket as the single source of truth. When the lambda automation function runs, it compares the information in loaded mapping definitions and assignments in the current environment. So it's able to find and address the drifts by re-provisioning the missing assignments and removing the additional assignments from IAM Identity Center.

  The following s3 bucket policy will block all PutObject/DeleteObject actions to this IAM Identity Center s3 bucket, Except the privileged automation roles. This ensures no one other than privileged automation pipeline role is able to change the content of the mapping definition file in s3 bucket.

          - Sid: OnlyAllowObjectUpdateRole1
            Action:
              - s3:DeleteObject
              - s3:DeleteObjectVersion
              - s3:PutObject
              - s3:PutObjectAcl
            Effect: Deny
            Principal: "*"
            Resource:
              !Sub arn:aws:s3:::${rS3Bucket}/*
            Condition:
              ArnNotLike:
                aws:PrincipalArn:
                  - !Sub "arn:aws:iam::${AWS::AccountId}:role/ICAutoPipelineCodeBuildRole"
                  - !Ref ICAutomationAdminArn

• Another bucket policy blocks all PutBucketPolicy and DeleteBucketPolicy actions if those request are not from AWSCloudFormationStackSetExecutionRole or privileged automation role.

          - Sid: OnlyAllowObjectUpdateRole2
            Action:
              - s3:PutBucketPolicy
              - s3:DeleteBucketPolicy
            Effect: Deny
            Principal: "*"
            Resource:
              !Sub arn:aws:s3:::${rS3Bucket}
            Condition:
              ArnNotLike:
                aws:PrincipalArn:
                  - !Sub "arn:aws:iam::${AWS::AccountId}:role/ICAutoPipelineCodeBuildRole"
                  - !Ref ICAutomationAdminArn

• There are 2 optional AWS event rules in the identity-center-automation.template:

  • ICManualActionDetectionRule1
    • Monitor the APIs from source 'sso.amazonaws.com'
  • ICManualActionDetectionRule2
    • Monitor the APIs from source 'sso-directory.amazonaws.com'

These 2 event rules will trigger the lambda function when AWS detects manual write changes to IAM Identity Center. Those AWS events will also trigger the lambda function to send out Email notification to administrators via SNS service.

• The identity-center-auto-permissionsets Lambda function will make "ProvisionPermissionSet" IAM Identity Center API call to update assignment status after it detects any updates to the existing permission sets.

• This solution will detach the permission set from all mapped accounts before deleting.

• This solution detects the API calls "CreateAccount" and "InviteAccountToOrganization" and uses them to trigger the IAM Identity Center group assignment tasks.

• The solution covers this use case. For example, we can add following content to "target-mapping-definition.json" file, so that lambda function will perform 2 separate assignments so we can attach this IAM Identity Center group to account 111111111111 and 123456789012 with permission set A and attach the same IAM Identity Center group to account 888888888888 and 999999999999 with permission set B:

  [
      {
          "TargetGroupName": "Target_Group_A",
          "PermissionSetName": [
              "<Name_permission_set_A>"  ],
          "TargetAccountid": [
              "111111111111",
              "123456789012"
          ]
      },
      {
          "TargetGroupName": "Target_Group_B",
          "PermissionSetName": [
              "<Name_permission_set_B>" ],
          "TargetAccountid": [
              "888888888888",
              "999999999999"
          ]
      },
      {       ....
      }
  ]

• The new AD or Identity Center group can be added by updating the global or target mapping JSON file.

• The new AD or Identity Center group can be added by updating the global or target mapping JSON file.

• We need to first create a new permission set definition JSON file for the new permission set. Once the new permission set is created in the Management account, then update the Identity Center group mapping JSON file to trigger the lambda function.

1. Example of permission set file (random account ids):

   Note: This solution(version 1.1.0 or newer) supports 1)customer managed policy and 2) session duration feature in the permission set definition file:

   1. Only use the "CustomerPolicies" object in the definition file if you need to apply customer managed policy to your permission set. When you create a permission the set with a customer managed policy, you MUST create an IAM policy with the same name and path in each AWS account where IAM Identity Center assigns your permission set. If you are specifying a custom path, make sure to specify the same path in each AWS account.
   2. You can apply custom permission set session duration for selected permission by adding "Session_Duration" in the mapping file (e.g 1-example-admin). You can set your own default permission set "SessionDuration" in the identity-center-automation.template or using identity-center-stacks-parameters.json file, current default value is 1 hour.
      • To change the "Session_Duration" on existing permission set:
        • Option 1) Recreate the permission set using CICD pipeline
        • Option 2) Update the both "Session_Duration" and "Description" section in the definition file and re-run the pipeline.

{
    "Name": "1-example-admin",
    "Description": "1-example-admin",
    "Session_Duration": "PT12H",
    "Tags": [
        {
            "Key": "identity-center-solution",
            "Value": "example"
        }
    ],
    "ManagedPolicies": [
        {
            "Name": "AdministratorAccess",
            "Arn": "arn:aws:iam::aws:policy/AdministratorAccess"
        }
    ],
    "CustomerPolicies": [
        {
            "Name": "customer-managed-policy-1",
            "Path": "/IAM-path-example/"
        },
        {
            "Name": "customer-managed-policy-2",
            "Path": "/"
        }
    ],
    "InlinePolicies": []
}

2. Example of global mapping file:

[
    {
        "GlobalGroupName": "Example_1-global-admin",
        "PermissionSetName": [
            "1-example-admin"
        ],
        "TargetAccountid": "Global"
    },
    {
        "GlobalGroupName": "Example_2-global-reader",
        "PermissionSetName": [
            "2-example-readonly"
        ],
        "TargetAccountid": "Global"
    },
]

3. Example of target mapping file:

[
    {
        "TargetGroupName": "Example_9-splunk-admin",
        "PermissionSetName": [
            "9-ops-enterprisemonitoring"
        ],
        "TargetAccountid": [
            "123456789012"
        ]
    },
	  {
        "TargetGroupName": "Example_10-network-engineering",
        "PermissionSetName": [
            "10-ops-networking"
        ],
        "TargetAccountid": [
            "123456789012",
			"111111111111",
			"222222222222",
			"333333333333"
        ]
    }
]

• Tearing down Identity Center resources could interrupt your access to AWS accounts. Please make sure you have other IAM roles or users to login the accounts. The following steps will only remove the resources that provisioned by this solution. You will need to manually remove other permission sets or SIdentity CenterSO assigments that are created outside this automation.
  1. Replace all the mapping information with an empty list "[]" in global-mapping.json and target-mapping.json files. Then re-run the pipeline to let lambda remove all the Identity Center assignments.
  2. Delete all the permission set JSON files in the "permissions-set" folder Then re-run the pipeline to automatically remove all permission sets.
  3. Delete CloudFormation stack that was created with identity-center-automation.template.
  4. Delete CloudFormation stack that was created with identity-center-s3-bucket.template
  5. Delete CloudFormation stack that was created with code-pipeline-stack.template

1. For the issue with AWS CloudFormation stack, you can view the error message in the stack events and refer to Troubleshooting CloudFormation.
2. For AWS CodePipeline issue, you can review the error messages on the CodePipeline console. For IAM related issue, please check Troubleshooting AWS CodePipeline identity and access.
3. The default log groups for the automation lambda functions are /aws/lambda/ic-permissionsets-enabler, /aws/lambda/ic-auto-assignment-enabler and /aws/lambda/ic-alert-SNSnotification.

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