Managing Veeam backup encryption using IBM Cloud key management

Veeam Backup and Replication offers the ability to encrypt your backups using passwords, which function as a kind of envelope encryption key for the encryption keys protecting the actual data. Veeam works hard to protect these passwords from exposure, to the degree that Veeam support cannot recover your passwords. You can ensure the resiliency of these keys either with a password–encrypted backup of your Veeam configuration; or by using Veeam Backup Enterprise Manager, which can protect and recover these passwords using an asymmetric key pair managed by Enterprise Manager. However, neither of these offerings allows integration with an external key manager for key storage and lifecycle. As a result, you must implement automation if you want to achieve Veeam backup encryption without your administrators and operators having direct knowledge of your encryption passwords. Veeam provides a set of PowerShell encryption cmdlets for this purpose.

In this article, I will demonstrate how you can use IBM Cloud Key Protect or IBM Cloud Hyper Protect Crypto Services (HPCS) to create and manage your Veeam encryption passwords.

Authenticating with the IBM Cloud API

Our first step is to use an IBM Cloud service ID API key to authenticate with IBM Cloud IAM and obtain a limited–time token that we will provide as our authorization for Key Protect or HPCS APIs. For this purpose we will use IBM Cloud’s recently released private endpoint for the IAM token service, which allows us to avoid connection to the public internet provided we have enabled VRF and service endpoints in our account.

# Variables

$apikey = '...'

# URIs and script level settings

$tokenURI = 'https://private.iam.cloud.ibm.com/identity/token'
$ErrorActionPreference = 'Stop'
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

# Exchange IBM Cloud API key for token

$headers = @{Accept='application/json'}
$body = @{grant_type='urn:ibm:params:oauth:grant-type:apikey'; apikey=$apikey}
$tokenResponse = Invoke-RestMethod -Uri $tokenURI -Method POST -Body $body -Headers $headers

# Bearer token is now present in $tokenResponse.access_token

This token will be used in each of the following use cases.

Generating a password

In order to generate a new password for use with Veeam, we will use this token to call the Key Protect or HPCS API to generate an AES256 key and “wrap” (that is, encrypt) it with a root key. The service ID associated with our API key above needs Reader access to the Key Protect or HPCS instance to perform this operation. The following example uses the Key Protect private API endpoint; if you are using HPCS you will have a private API endpoint specific to your instance that looks something like https://api.private.us-south.hs-crypto.cloud.ibm.com:12345. In this script we use a pre–selected Key Protect or HPCS instance (identified by $kms) and root key within that instance (identified by $crk).

# Variables

$kms = 'nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnnn'
$crk = 'nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnnn'

# URIs and script level settings

$kmsURIbase = 'https://private.us-south.kms.cloud.ibm.com/api/v2/keys/'
$ErrorActionPreference = 'Stop'
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

# Perform wrap operation with empty payload to generate an AES 256 key that will be used as password

$headers = @{Accept='application/json'; 'content-type'='application/vnd.ibm.kms.key_action_wrap+json'; 'bluemix-instance'=$kms; Authorization=("Bearer " + $tokenResponse.access_token); 'correlation-id'=[guid]::NewGuid()}
$body = @{}
$wrapResponse = Invoke-RestMethod -Uri ($kmsURIbase + $crk + "/actions/wrap") -Method POST -Body (ConvertTo-Json $body) -Headers $headers

# Plaintext key is present in $wrapResponse.plaintext, and wrapped key in $wrapResponse.ciphertext

After generating the key, we create a new Veeam password with that content. The output of the wrap operation includes both the plaintext key itself and also the wrapped form of the key. Our password can only be extracted from this wrapped ciphertext by someone who has sufficient access to the root key. We should store this wrapped form somewhere for recovery purposes; for the purposes of this example I am storing it as the password description together with a name for the password, $moniker, which in the full script is collected earlier from the script parameters.

$plaintext = ConvertTo-SecureString $wrapResponse.plaintext -AsPlainText -Force
$wdek = $wrapResponse.ciphertext
Remove-Variable wrapResponse

# Store this key as a new Veeam encryption key. Retain it in base64 format for simplicity.

Add-VBREncryptionKey -Password $plaintext -Description ($moniker + " | " + $wdek)

Write-Output ("Created new key " + $moniker)

You can see the full example script create-key.ps1 in GitHub.

Re–wrap a password

Because Veeam does not directly integrate with an external key manager, we have extra work to do if we want to respond to rotation of the root key, or to cryptographic erasure. The following code uses the rewrap API call to regenerate the wrapped form of our key in case the root key has been rotated. This ensures that our backup copy of the key is protected by the latest version of the root key.

# Perform rewrap operation to rewrap our key
# If this operation fails, it is possible your root key has been revoked and you should destroy the Veeam key

$headers = @{Accept='application/json'; 'content-type'='application/vnd.ibm.kms.key_action_rewrap+json'; 'bluemix-instance'=$kms; Authorization=("Bearer " + $tokenResponse.access_token); 'correlation-id'=[guid]::NewGuid()}
$body = @{ciphertext=$wdek}
$rewrapResponse = Invoke-RestMethod -Uri ($kmsURIbase + $crk + "/actions/rewrap") -Method POST -Body (ConvertTo-Json $body) -Headers $headers

Note that this API call will fail with a 4xx error in cases that include the revocation of the root key. In this case, if the root key has been purposely revoked, it is appropriate for you to remove your Veeam password to accomplish the cryptographic erasure. However, assuming that the rewrap is successful, we should update our saved copy of the wrapped form of the key to this latest value. In this example, $key is a PSCryptoKey object that was earlier collected from the Get-VBREncryptionKey cmdlet, and represents the key whose description will be updated:

$newWdek = $rewrapResponse.ciphertext
Remove-Variable rewrapResponse

# Update the existing description of the Veeam encryption key to reflect the updated wrapped version

Set-VBREncryptionKey -EncryptionKey $key.Description -Description ($moniker + " | " + $newWdek)

Write-Output ("Rewrapped key " + $moniker)

You can see the full example script rewrap-key.ps1 in GitHub.

Recover a password

Within a single site the above approach is sufficient. For additional resilience, you can use Veeam backup copy jobs to copy your data to a remote location. If you have a Veeam repository in a remote site and you lose the VBR instance and repositories in your primary site, Veeam enables you to recover VBR in the remote site from an encrypted configuration backup, after which you can restore backups from the repository in that site.

However, you need to plan carefully for recovery not only of your data but also your encryption keys. Ideally, you would choose to protect both the Veeam configuration backup and the VM backups using keys that are protected by IBM Cloud Key Protect or HPCS. This means that for configuration backups and for remote backups, you should choose a Key Protect or HPCS key manager instance in the remote location so that your key management in the remote site is not subject to the original site failure. You might therefore be using two key manager instances: one local key manager instance for keys to protect your local backup jobs used for common recovery operations, and another remote instance for keys to protect your configuration backup and your copy backup jobs used in case of disaster.

This also implies that the key used to protect your configuration backups should be preserved in an additional location than your VBR instance and in a form other than a Veeam key object; in fact, the Veeam configuration restore process requires you to enter the password–key manually. You should store the key in its secure wrapped form, ideally alongside your Veeam configuration backup. You will then need to unwrap the key when you restore the configuration. In this example, the wrapped form of the key is expected to be one of the script arguments, and this underscores the need to protect this key with a key manager that will still be available in case of the original site failure:

# Perform unwrap operation

$headers = @{Accept='application/json'; 'content-type'='application/vnd.ibm.kms.key_action_unwrap+json'; 'bluemix-instance'=$kms; Authorization=("Bearer " + $tokenResponse.access_token); 'correlation-id'=[guid]::NewGuid()}
$body = @{ciphertext=$args[0]}
$unwrapResponse = Invoke-RestMethod -Uri ($kmsURIbase + $crk + "/actions/unwrap") -Method POST -Body (ConvertTo-Json $body) -Headers $headers

Write-Output ("Plaintext key: " + $unwrapResponse.plaintext)

Because this exposes your key to your administrator or operator, after restoring VBR from configuration backup, you should generate a new key for subsequent configuration backups.

You can see the full example script unwrap-key.ps1 in GitHub.

Summary

In this article, I’ve showed how you can use IBM Cloud key management APIs to generate and manage encryption keys for use with Veeam Backup and Replication. You can see full examples of the scripts excerpted above in GitHub. These scripts are a basic example that are intended to be extended and customized for your own environment. You should take special care to consider how you manage and protect your IBM Cloud service ID API keys, and how you save and manage the wrapped form of the keys generated by these scripts. Most likely you would store all of these in your preferred secret manager.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s