Disable Automatic IAM Role Grants for Default Service Accounts

01 Sign in to Google Cloud Management Console with the organizational unit credentials.

02 Click on the deployment selector from the top navigation bar, select ALL to list all the existing deployments, then choose the Google Cloud organization that you want to examine.

03 Navigate to Cloud Identity and Access Management (IAM) dashboard at https://console.cloud.google.com/iam-admin/iam.

04 In the navigation panel, select Organization Policies to access the list with the cloud organization policies available for your GCP organization.

05 Click inside the Filter by policy name or ID filter box, select Disable Automatic IAM Grants for Default Service Accounts to return only the “Disable Automatic IAM Grants for Default Service Accounts” organization policy.

06 Click on the name of the GCP organization policy returned at the previous step.

07 On the Policy details page, under Effective policy, check the Enforcement configuration attribute status. If the Enforcement attribute status is set to Not enforced, the policy is not enforced within your organization, therefore the restriction of auto enabling IAM role grant for default service accounts is not enabled for the selected Google Cloud organization.

08 While viewing the Disable Automatic IAM Grants for Default Service Accounts policy details page, click on the deployment selector from the top navigation bar and select the relevant project you wish to inspect.

09 On the Policy details page, under Effective policy, check the Enforcement configuration attribute status. If the Enforcement attribute status is set to Not enforced, the policy is not enabled for the chosen project.

10 Repeat steps no. 2 – 9 for each organization available in your Google Cloud account.

01 Run organizations list command (Windows/macOS/Linux) using custom query filters to list the ID of each GCP organization created within your Google Cloud account:

gcloud organizations list
  --format="table(name)"

02 The command output should return the requested organization identifiers (IDs):

ID
112233441122
123412341234

03 Run resource-manager org-policies describe command (Windows/macOS/Linux) using the ID of the GCP organization that you want to reconfigure as identifier parameter, to describe the enforcement configuration of the “Disable Automatic IAM Grants for Default Service Accounts” policy (i.e. "iam.automaticIamGrantsForDefaultServiceAccounts"), available for the selected organization:

gcloud alpha resource-manager org-policies describe
  "iam.automaticIamGrantsForDefaultServiceAccounts"
  --effective
  --organization=112233441122
  --format="table(booleanPolicy)"

04 The command request should return the requested configuration information:

BOOLEAN_POLICY
{}

05 Run resource-manager org-policies describe command (Windows/macOS/Linux) using the ID of the GCP project that you want to inspect:

gcloud alpha resource-manager org-policies describe
  "iam.automaticIamGrantsForDefaultServiceAccounts"
  --effective
  --project=myProject123
  --format="table(booleanPolicy)"

06 The command request should return the requested configuration information:

BOOLEAN_POLICY
{}

07 Repeat step no. 3 - 6 for each organization created within your Google Cloud account.

01 Sign in to Google Cloud Management Console with the organizational unit credentials.

02 Click on the deployment selector from the top navigation bar, select ALL to list all the existing deployments, then choose the Google Cloud organization that you want to reconfigure.

03 Navigate to Cloud Identity and Access Management (IAM) dashboard at https://console.cloud.google.com/iam-admin/iam.

04 In the navigation panel, select Organization Policies to access the list with the cloud organization policies available for your GCP organization.

05 Click inside the Filter by policy name or ID box, select Name and Disable Automatic IAM Grants for Default Service Accounts to list only the “Disable Automatic IAM Grants for Default Service Accounts” policy.

06 Click on the name of the GCP organization policy listed at the previous step.

07 On the Policy details page, click on the EDIT button from the dashboard top menu to edit the selected policy.

08 On the Edit policy configuration page, perform the following actions:

1. Under Applies to, select Customize to choose the type of the policy to apply (i.e. customized policy).
2. Under Enforcement, select On to enforce the "iam.automaticIamGrantsForDefaultServiceAccounts" constraint. This policy constraint disables the automatic IAM role grant for default service accounts in the selected Google Cloud organization.
3. Click SAVE to apply the changes and enforce the “Disable Automatic IAM Grants for Default Service Accounts” policy constraints.

09 Click on the deployment selector from the top navigation bar, select the project that you want to reconfigure and return to the same Edit policy configuration page. If required, follow the same navigation steps mentioned from steps 3 -7.

10 On the Edit policy configuration page, under Applies to select Inherit parent's policy and click save to apply policy to the individual project.

11 If required, repeat steps no. 2 – 10 to enable the policy for other organizations and projects available in your Google Cloud environment.

01 Run resource-manager org-policies enable-enforce command (Windows/macOS/Linux) using the ID of the Google Cloud Platform (GCP) organization that you want to reconfigure as identifier parameter, to enforce the “Disable Automatic IAM Grants for Default Service Accounts” policy (i.e. "iam.automaticIamGrantsForDefaultServiceAccounts") for the selected GCP organization:

gcloud alpha resource-manager org-policies enable-enforce
  "iam.automaticIamGrantsForDefaultServiceAccounts"
  --organization=112233441122

02 The command request should return the reconfigured organization policy metadata:

booleanPolicy:
  enforced: true
constraint: constraints/iam.automaticIamGrantsForDefaultServiceAccounts
etag: aabbccddabcd
updateTime: '2020-07-14T12:00:00.000Z'

03 Run resource-manager org-policies enable-enforce command (Windows/macOS/Linux) using the ID of the Google Cloud Platform (GCP) project that you want to reconfigure.:

gcloud alpha resource-manager org-policies enable-enforce
  "iam.automaticIamGrantsForDefaultServiceAccounts"
  --project=myproject123

04 The command request should return the reconfigured organization policy metadata:

booleanPolicy:
  enforced: true
constraint: constraints/storage.uniformBucketLevelAccess
etag: aabbccddabcd
updateTime: '2020-07-15T20:00:00.000Z'

05 If required, repeat step no. 1 - 4 to enforce the policy for other GCP organizations and projects created within your Google Cloud environment.