Validate Azure Stack Hub PKI certificates

Article
04/04/2023

The Azure Stack Hub Readiness Checker tool described in this article is available from the PowerShell Gallery. Use the tool to validate that generated public key infrastructure (PKI) certificates are suitable for pre-deployment. Validate certificates by leaving enough time to test and reissue certificates if necessary.

The Readiness Checker tool performs the following certificate validations:

Parse PFX
Checks for valid PFX file, correct password, and whether the public information is protected by the password.
Expiry Date
Checks for minimum validity of seven days.
Signature algorithm
Checks that the signature algorithm isn't SHA1.
Private Key
Checks that the private key is present and is exported with the local machine attribute.
Cert chain
Checks certificate chain is intact including a check for self-signed certificates.
DNS names
Checks the SAN contains relevant DNS names for each endpoint or if a supporting wildcard is present.
Key usage
Checks if the key usage contains a digital signature and key encipherment and checks if enhanced key usage contains server authentication and client authentication.
Key size
Checks if the key size is 2048 or larger.
Chain order
Checks the order of the other certificates validating that the order is correct.
Other certificates
Ensure no other certificates have been packaged in PFX other than the relevant leaf certificate and its chain.

Important

The PKI certificate is a PFX file and password should be treated as sensitive information.

Prerequisites

Your system should meet the following prerequisites before validating PKI certificates for an Azure Stack Hub deployment:

Microsoft Azure Stack Hub Readiness Checker.
SSL Certificate(s) exported following the preparation instructions.
DeploymentData.json.
Windows 10 or Windows Server 2016.

Perform core services certificate validation

Use these steps to validate the Azure Stack Hub PKI certificates for deployment and secret rotation:

Install AzsReadinessChecker from a PowerShell prompt (5.1 or above) by running the following cmdlet:
```
Install-Module Microsoft.AzureStack.ReadinessChecker -Force -AllowPrerelease
```

Create the certificate directory structure. In the example below, you can change <C:\Certificates\Deployment> to a new directory path of your choice.

New-Item C:\Certificates\Deployment -ItemType Directory

$directories = 'ACSBlob', 'ACSQueue', 'ACSTable', 'Admin Extension Host', 'Admin Portal', 'ARM Admin', 'ARM Public', 'KeyVault', 'KeyVaultInternal', 'Public Extension Host', 'Public Portal'

$destination = 'C:\Certificates\Deployment'

$directories | % { New-Item -Path (Join-Path $destination $PSITEM) -ItemType Directory -Force}

Note

AD FS and Graph are required if you're using AD FS as your identity system. For example:

$directories = 'ACSBlob', 'ACSQueue', 'ACSTable', 'ADFS', 'Admin Extension Host', 'Admin Portal', 'ARM Admin', 'ARM Public', 'Graph', 'KeyVault', 'KeyVaultInternal', 'Public Extension Host', 'Public Portal'

Place your certificate(s) in the appropriate directories created in the previous step. For example:
- C:\Certificates\Deployment\ACSBlob\CustomerCertificate.pfx
- C:\Certificates\Deployment\Admin Portal\CustomerCertificate.pfx
- C:\Certificates\Deployment\ARM Admin\CustomerCertificate.pfx

In the PowerShell window, change the values of RegionName, FQDN and IdentitySystem appropriate to the Azure Stack Hub environment and run the following cmdlet:

$pfxPassword = Read-Host -Prompt "Enter PFX Password" -AsSecureString 
Invoke-AzsHubDeploymentCertificateValidation -CertificatePath C:\Certificates\Deployment -pfxPassword $pfxPassword -RegionName east -FQDN azurestack.contoso.com -IdentitySystem AAD

Check the output and ensure that all certificates pass all tests. For example:

Invoke-AzsHubDeploymentCertificateValidation v1.2005.1286.272 started.
Testing: KeyVaultInternal\KeyVaultInternal.pfx
Thumbprint: E86699****************************4617D6
    PFX Encryption: OK
    Expiry Date: OK
    Signature Algorithm: OK
    DNS Names: OK
    Key Usage: OK
    Key Length: OK
    Parse PFX: OK
    Private Key: OK
    Cert Chain: OK
    Chain Order: OK
    Other Certificates: OK
Testing: ARM Public\ARMPublic.pfx
Thumbprint: 8DC4D9****************************69DBAA
    PFX Encryption: OK
    Expiry Date: OK
    Signature Algorithm: OK
    DNS Names: OK
    Key Usage: OK
    Key Length: OK
    Parse PFX: OK
    Private Key: OK
    Cert Chain: OK
    Chain Order: OK
    Other Certificates: OK
Testing: Admin Portal\AdminPortal.pfx
Thumbprint: 6F9055****************************4AC0EA
    PFX Encryption: OK
    Expiry Date: OK
    Signature Algorithm: OK
    DNS Names: OK
    Key Usage: OK
    Key Length: OK
    Parse PFX: OK
    Private Key: OK
    Cert Chain: OK
    Chain Order: OK
    Other Certificates: OK
Testing: Public Portal\PublicPortal.pfx


Log location (contains PII): C:\Users\[*redacted*]\AppData\Local\Temp\AzsReadinessChecker\AzsReadinessChecker.log
Report location (contains PII): C:\Users\[*redacted*]\AppData\Local\Temp\AzsReadinessChecker\AzsReadinessCheckerReport.json
Invoke-AzsHubDeploymentCertificateValidation Completed

To validate certificates for other Azure Stack Hub services, change the value for -CertificatePath. For example:

# App Services
Invoke-AzsHubAppServicesCertificateValidation -CertificatePath C:\Certificates\AppServices -pfxPassword $pfxPassword -RegionName east -FQDN azurestack.contoso.com

# DBAdapter
Invoke-AzsHubDBAdapterCertificateValidation -CertificatePath C:\Certificates\DBAdapter -pfxPassword $pfxPassword -RegionName east -FQDN azurestack.contoso.com

# EventHubs
Invoke-AzsHubEventHubsCertificateValidation -CertificatePath C:\Certificates\EventHubs -pfxPassword $pfxPassword -RegionName east -FQDN azurestack.contoso.com

Each folder should contain a single PFX file for the certificate type. If a certificate type has multi-certificate requirements, nested folders for each individual certificate are expected and name-sensitive. The following code shows an example folder/certificate structure for all certificate types, and the appropriate value for -CertificatePath.

C:\>tree c:\SecretStore /A /F
    Folder PATH listing
    Volume serial number is 85AE-DF2E
    C:\SECRETSTORE
    \---AzureStack
        +---CertificateRequests
        \---Certificates
            +---AppServices         # Invoke-AzsCertificateValidation `
            |   +---API             # -CertificatePath C:\Certificates\AppServices
            |   |       api.pfx     
            |   |
            |   +---DefaultDomain
            |   |       wappsvc.pfx
            |   |
            |   +---Identity
            |   |       sso.pfx
            |   |
            |   \---Publishing
            |           ftp.pfx
            |
            +---DBAdapter           # Invoke-AzsCertificateValidation `
            |       dbadapter.pfx   # -CertificatePath C:\Certificates\DBAdapter
            |                       
            |
            +---Deployment          # Invoke-AzsCertificateValidation `
            |   +---ACSBlob         # -CertificatePath C:\Certificates\Deployment
            |   |       acsblob.pfx 
            |   |
            |   +---ACSQueue
            |   |       acsqueue.pfx
           ./. ./. ./. ./. ./. ./. ./.    <- Deployment certificate tree trimmed.
            |   \---Public Portal
            |           portal.pfx
            |
            \---EventHubs           # Invoke-AzsCertificateValidation `
                    eventhubs.pfx   # -CertificatePath C:\Certificates\EventHubs

Known issues

Symptom: Tests are skipped

Cause: AzsReadinessChecker skips certain tests if a dependency isn't met:

Other certificates are skipped if certificate chain fails.

Testing: ACSBlob\singlewildcard.pfx
     Read PFX: OK
     Signature Algorithm: OK
     Private Key: OK
     Cert Chain: OK
     DNS Names: Fail
     Key Usage: OK
     Key Size: OK
     Chain Order: OK
     Other Certificates: Skipped
Details:
The certificate records '*.east.azurestack.contoso.com' do not contain a record that is valid for '*.blob.east.azurestack.contoso.com'. Please refer to the documentation for how to create the required certificate file.
The other certificates check was skipped because cert chain and/or DNS names failed. Follow the guidance to remediate those issues and recheck. 

Log location (contains PII): C:\Users\username\AppData\Local\Temp\AzsReadinessChecker\AzsReadinessChecker.log
Report location (contains PII): C:\Users\username\AppData\Local\Temp\AzsReadinessChecker\AzsReadinessCheckerReport.json
Invoke-AzsCertificateValidation Completed

Resolution: Follow the tool's guidance in the details section under each set of tests for each certificate.

Symptom: HTTP CRL checking fails despite having an HTTP CDP written to x509 extensions.

Cause: Currently, the AzsReadinessChecker can't check for HTTP CDP in some languages.

Resolution: Run validation with OS language set to EN-US.

Certificates

Directory	Certificate
ACSBlob	`wildcard_blob_<region>_<externalFQDN>`
ACSQueue	`wildcard_queue_<region>_<externalFQDN>`
ACSTable	`wildcard_table_<region>_<externalFQDN>`
Admin Extension Host	`wildcard_adminhosting_<region>_<externalFQDN>`
Admin Portal	`adminportal_<region>_<externalFQDN>`
ARM Admin	`adminmanagement_<region>_<externalFQDN>`
ARM Public	`management_<region>_<externalFQDN>`
KeyVault	`wildcard_vault_<region>_<externalFQDN>`
KeyVaultInternal	`wildcard_adminvault_<region>_<externalFQDN>`
Public Extension Host	`wildcard_hosting_<region>_<externalFQDN>`
Public Portal	`portal_<region>_<externalFQDN>`

Next steps

Once your certificates are validated by AzsReadinessChecker, you're ready to use them for Azure Stack Hub deployment or post-deployment secret rotation.

For deployment, securely transfer your certificates to your deployment engineer so that they can copy them onto the deployment virtual machine host as specified in Azure Stack Hub PKI requirements - Mandatory certificates.
For secret rotation, see Rotate secrets in Azure Stack Hub. Rotation of value-add resource provider certificates is covered in the Rotate external secrets section.

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