Encrypt recovery data in the database

Straipsnis
10/04/2022

Applies to: Configuration Manager (current branch)

When you create a BitLocker management policy, Configuration Manager deploys the recovery service to a management point. On the Client Management page of the BitLocker management policy, when you Configure BitLocker Management Services, the client backs up key recovery information to the site database. This information includes BitLocker recovery keys, recovery packages, and TPM password hashes. When users are locked out of their protected device, you can use this information to help them recover access to the device.

Given the sensitive nature of this information, you need to protect it. Configuration Manager requires an HTTPS connection between the client and the recovery service to encrypt the data in transit across the network. For more information, see Encrypt recovery data over the network.

Consider also encrypting this data when stored in the site database. If you install a SQL Server certificate, Configuration Manager encrypts your data in SQL.

If you don't want to create a BitLocker management encryption certificate, opt-in to plain-text storage of the recovery data. When you create a BitLocker management policy, enable the option to Allow recovery information to be stored in plain text.

Note

Another layer of security is to encrypt the entire site database. If you enable encryption on the database, there aren't any functional issues in Configuration Manager.

Encrypt with caution, especially in large-scale environments. Depending upon the tables you encrypt and the version of SQL, you may notice up to a 25% performance degradation. Update your backup and recovery plans, so that you can successfully recover the encrypted data.

Note

Configuration Manager never removes or deletes recovery information for devices from the database, even if the client is inactive or deleted. This behavior is for security reasons. It helps with scenarios where a device is stolen but later recovered. For large environments, the impact to the database size is about 9 KB of data per encrypted volume.

SQL Server encryption certificate

Use this SQL Server certificate for Configuration Manager to encrypt BitLocker recovery data in the site database. You can create a self-signed certificate using a script in SQL Server.

Alternatively, you can use your own process to create and deploy this certificate, as long as it meets the following requirements:

The name of the BitLocker management encryption certificate must be BitLockerManagement_CERT.
Encrypt this certificate with a database master key.
The following SQL Server users need Control permissions on the certificate:
- RecoveryAndHardwareCore
- RecoveryAndHardwareRead
- RecoveryAndHardwareWrite
Deploy the same certificate at every site database in your hierarchy.
Create the certificate with the latest version of SQL Server.
Important
- Certificates created with SQL Server 2016 or later are compatible with SQL Server 2014 or earlier.
- Certificates created with SQL Server 2014 or earlier aren't compatible with SQL Server 2016 or later.

Manage the encryption certificate on SQL Server upgrade

If your site database is on SQL Server 2014 or earlier, before you upgrade SQL Server to version 2016 or later, use the following procedure to rotate the certificate to a supported version.

On an instance of SQL Server running the latest available version, at least version 2016:
1. Create a new certificate
2. Back up the new certificate
On the SQL Server instance with the encrypted site database that you plan to upgrade:
1. Move the existing certificate on the site database server SQL Server instance to another name.
2. Restore the new certificate.
3. Rotate the new certificate in for the existing certificate. Use the provided SQL function [RecoveryAndHardwareCore].[RecryptKey]

Important

If you upgrade SQL Server before you rotate the certificate, contact Microsoft Support for assistance with a work around.

You can also use this process if your business requirements specify that you need to regularly renew this certificate.

Example scripts

These SQL scripts are examples to create and deploy a BitLocker management encryption certificate in the Configuration Manager site database.

Create certificate

This sample script does the following actions:

Creates a certificate
Sets the permissions
Creates a database master key

Before you use this script in a production environment, change the following values:

Site database name (CM_ABC)
Password to create the master key (MyMasterKeyPassword)
Certificate expiry date (20391022)

USE CM_ABC
IF NOT EXISTS (SELECT name FROM sys.symmetric_keys WHERE name = '##MS_DatabaseMasterKey##')
BEGIN
    CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'MyMasterKeyPassword'
END

IF NOT EXISTS (SELECT name from sys.certificates WHERE name = 'BitLockerManagement_CERT')
BEGIN
    CREATE CERTIFICATE BitLockerManagement_CERT AUTHORIZATION RecoveryAndHardwareCore
    WITH SUBJECT = 'BitLocker Management',
    EXPIRY_DATE = '20391022'

    GRANT CONTROL ON CERTIFICATE ::BitLockerManagement_CERT TO RecoveryAndHardwareRead
    GRANT CONTROL ON CERTIFICATE ::BitLockerManagement_CERT TO RecoveryAndHardwareWrite
END

Note

The certificate expiration date isn't checked or enforced by SQL Server when the certificate is used for database encryption as is the case here.

If your business requirements specify that you regularly renew this certificate, use the same process to Manage the encryption certificate on SQL Server upgrade.

Back up certificate

This sample script backs up a certificate. When you save the certificate to a file, you can then restore it to other site databases in the hierarchy.

Before you use this script in a production environment, change the following values:

Site database name (CM_ABC)
File path and name (C:\BitLockerManagement_CERT_KEY)
Export key password (MyExportKeyPassword)

USE CM_ABC
BACKUP CERTIFICATE BitLockerManagement_CERT TO FILE = 'C:\BitLockerManagement_CERT'
    WITH PRIVATE KEY ( FILE = 'C:\BitLockerManagement_CERT_KEY',
        ENCRYPTION BY PASSWORD = 'MyExportKeyPassword')

Important

Always back up the certificate. In case you need to recover the site database, you may need to restore the certificate to regain access to the recovery keys.

Store the exported certificate file and associated password in a secure location.

Restore certificate

This sample script restores a certificate from a file. Use this process to deploy a certificate that you created on another site database.

Before you use this script in a production environment, change the following values:

Site database name (CM_ABC)
Master key password (MyMasterKeyPassword)
File path and name (C:\BitLockerManagement_CERT_KEY)
Export key password (MyExportKeyPassword)

USE CM_ABC
IF NOT EXISTS (SELECT name FROM sys.symmetric_keys WHERE name = '##MS_DatabaseMasterKey##')
BEGIN
    CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'MyMasterKeyPassword'
END

IF NOT EXISTS (SELECT name from sys.certificates WHERE name = 'BitLockerManagement_CERT')
BEGIN

CREATE CERTIFICATE BitLockerManagement_CERT AUTHORIZATION RecoveryAndHardwareCore
FROM FILE  = 'C:\BitLockerManagement_CERT'
    WITH PRIVATE KEY ( FILE = 'C:\BitLockerManagement_CERT_KEY',
        DECRYPTION BY PASSWORD = 'MyExportKeyPassword')

GRANT CONTROL ON CERTIFICATE ::BitLockerManagement_CERT TO RecoveryAndHardwareRead
GRANT CONTROL ON CERTIFICATE ::BitLockerManagement_CERT TO RecoveryAndHardwareWrite
END

Verify certificate

Use this SQL script to verify that SQL Server successfully created the certificate with the required permissions.

USE CM_ABC
declare @count int
select @count = count(distinct u.name) from sys.database_principals u
join sys.database_permissions p on p.grantee_principal_id = u.principal_id or p.grantor_principal_id = u.principal_id
join sys.certificates c on c.certificate_id = p.major_id
where u.name in('RecoveryAndHardwareCore', 'RecoveryAndHardwareRead', 'RecoveryAndHardwareWrite') and
c.name = 'BitLockerManagement_CERT' and p.permission_name like 'CONTROL'
if(@count >= 3) select 1
else select 0

If the certificate is valid, the script returns a value of 1.

Next steps

Deploy BitLocker management client

Bendrinti naudojant

Encrypt recovery data in the database

SQL Server encryption certificate

Manage the encryption certificate on SQL Server upgrade

Example scripts

Create certificate

Back up certificate

Restore certificate

Verify certificate

See also

Next steps

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