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1.3 Ensure Access Review is Set Up for External Users in Azure AD Privileged Identity Management (Manual)
Profile Applicability
• Level 2
Description
This recommendation extends guest access review by utilizing the Azure AD Privileged Identity Management feature provided in Azure AD Premium P2.
Azure AD is extended to include Azure AD B2B collaboration, allowing you to invite people from outside your organization to be guest users in your cloud account and sign in with their own work, school, or social identities. Guest users allow you to share your company's applications and services with users from any other organization, while maintaining control over your own corporate data.
Work with external partners, large or small, even if they don't have Azure AD or an IT department. A simple invitation and redemption process lets partners use their own credentials to access your company's resources a a guest user.
Rationale
Guest users in the Azure AD are generally required for collaboration purposes in Office 365, and may also be required for Azure functions in enterprises with multiple Azure tenants. Guest users should be reviewed on a regular basis, at least annually. Guest users should not be granted administrative roles where possible.
Guest users are typically added outside your employee on-boarding/off-boarding process and could potentially be overlooked indefinitely, leading to a potential vulnerability.
Guest users should be reviewed on a monthly basis to ensure that inactive and unneeded accounts are removed.
Impact
Until you have a business need to provide guest access to any user, avoid creating guest users. If guest accounts are being used, they should be removed when no longer required.
Audit
From Azure Portal
From the Azure Portal home page click the portal menu in the top left.
Select
Azure Active Directory
Select
Users
in the left column under theManage
heading.Next to the search box select the
filter
option.Search for and select
User Type
In the third drop down
Value
selectGuest
.Review the guest users in your
Active Directory
.
From Azure CLI
Run the following command:
az ad user list -Filter "UserType eq 'Guest'"
From Azure Powershell
Run the following command:
Get-AzureADUser -Filter "UserType eq 'Guest'"
Remediation
From Azure Portal
From the Azure Portal home page click the portal menu in the top left.
Select
Azure Active Directory
Select
Users
in the left column under theManage
heading.Next to the search box select the
filter
option.Search for and select
User Type
In the third drop down
Value
selectGuest
.Review the guest users in your Active Directory.
For those you wish to delete, select the checkbox on the left then the
Delete
option in the top row.
From Azure CLI
With the information from the audit procedure, to remove a Guest user run the following command with their User Principal Value.
Remove-AzureADUser -ObjectId "<UserPrincipalName@emailaddress.com"
From Azure Powershell
With the information from the audit procedure, to remove a Guest user run the following command with their User Principal Value.
Remove-AzureADUser -ObjectId "<UserPrincipalName@emailaddress.com>"
References
https://docs.microsoft.com/en-us/azure/active-directory/b2b/user-properties
https://docs.microsoft.com/en-us/azure/active-directory/fundamentals/add-users-azure-active-directory#delete-a-user
https://docs.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-privileged-access#pa-3-review-and-reconcile-user-access-regularly
https://docs.microsoft.com/en-us/azure/active-directory/governance/manage-guest-access-with-access-reviews
https://www.microsoft.com/en-us/security/business/identity-access-management/azure-ad-pricing