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Secure password transmission to an initialization script

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Updated at November 22, 2024

When creating a VM from an image with the Windows OS, you can use an initialization script. For example, you can set up username-password pairs for the administrator and other system users. To protect sensitive data, use Yandex Lockbox functionality instead of explicitly specifying settings in the script.

In this tutorial, you will create a VM with the Windows OS using an initialization script which will get username-password pairs of system users from Yandex Lockbox.

To create a VM and protect confidential information in the initialization script:

  1. Create a service account.
  2. Create a KMS key.
  3. Create a secret.
  4. Create a VM.
  5. Log in to Windows.

If you no longer need the resources you created, delete them.

Getting started

Sign up for Yandex Cloud and create a billing account:

  1. Go to the management console and log in to Yandex Cloud or create an account if you do not have one yet.
  2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one.

If you have an active billing account, you can go to the cloud page to create or select a folder for your infrastructure to operate in.

Learn more about clouds and folders.

The infrastructure support cost includes:

  • Fee for VMs (see Yandex Compute Cloud pricing).
  • Fee for image use (depends on the image).
  • Fee for using a KMS key (see KMS pricing).
  • Fee for using a secret (see Yandex Lockbox pricing).

Create a service account

  1. In the management console, select the folder where you want to create a service account.
  2. In the list of services, select Identity and Access Management.
  3. Click Create service account.
  4. Enter a name for the service account, e.g., win-secret-sa.
  5. Click Create.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

Run the command below to create a service account, specifying win-secret-sa as its name:

yc iam service-account create --name win-secret-sa

Where name is the service account name.

Result:

id: ajehr0to1g8b********
folder_id: b1gv87ssvu49********
created_at: "2024-03-15T09:03:11.665153755Z"
name: win-secret-sa

To create a service account, use the ServiceAccountService/Create gRPC API call or the create REST API method for the ServiceAccount resource.

Create a KMS key

  1. Create an encryption key:

    1. In the management console, select the folder where you want to create a key.
    2. Select Key Management Service.
    3. In the left-hand panel, select Symmetric keys.
    4. Click Create key and specify the key attributes:
      • Name: win-secret-key.
      • Encryption algorithm: AES-256.
      • Leave the other parameters at their default settings.
    5. Click Create.

    The key is created together with its first version: click the key in the list to open the page with its attributes.

    Run this command:

    yc kms symmetric-key create \
  --name win-secret-key \
  --default-algorithm aes-256

    Where:

    • --name: Key name.
    • --default-algorithm: Encryption algorithm: aes-128, aes-192, or aes-256.

    Terraform allows you to quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. Configuration files store the infrastructure description in the HashiCorp Configuration Language (HCL). Terraform and its providers are distributed under the Business Source License.

    For more information about the provider resources, see the documentation on the Terraform website or the mirror.

    If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

    If you don't have Terraform, install it and configure the Yandex Cloud provider.

    To create a key:

    1. Describe the parameters of the yandex_kms_symmetric_key resource in the configuration file:

      resource "yandex_kms_symmetric_key" "key-a" {
  name              = "<key_name>"
  description       = "<key_description>"
  default_algorithm = "AES_128"
  rotation_period   = "8760h"
  lifecycle {
    prevent_destroy = true
  }
}

      Where:

      • name: Key name. The name format is as follows:

        • The name must be from 3 to 63 characters long.
        • It may contain lowercase Latin letters, numbers, and hyphens.
        • The first character must be a letter and the last character cannot be a hyphen.

      • description: Key description.

      • default_algorithm: Encryption algorithm. The possible values are AES-128, AES-192, or AES-256.

      • rotation_period: Rotation period (how often to change key versions). To create a key without automatic rotation, do not specify the rotation_period parameter.

      Warning

      Deleting a KMS key destroys all data encrypted with that key: the data becomes unrecoverable after the key is deleted. The lifecycle block is necessary to prevent users from destroying keys (e.g., with the terraform destroy command).

      For more information about resource parameters in Terraform, see the provider documentation.

    2. Check the configuration using this command:

      terraform validate

      If the configuration is correct, you will get this message:

      Success! The configuration is valid.

    3. Run this command:

      terraform plan

      The terminal will display a list of resources with parameters. No changes will be made at this step. If the configuration contains any errors, Terraform will point them out.

    4. Apply the configuration changes:

      terraform apply

    5. Confirm the changes: type yes into the terminal and press Enter.

      All the resources you need will then be created in the specified folder. You can check the new resources and their configuration using the management console or these CLI commands:

      yc kms symmetric-key list

    Use the create REST API method for the SymmetricKey resource or the SymmetricKeyService/Create gRPC API call.

  2. Assign the kms.keys.encrypterDercrypter role to the win-secret-sa service account:

    1. Go to the Access rights tab on the key page.
    2. Go to the Access bindings tab.
    3. Find the win-secret-sa account in the list and click .
    4. Click Edit roles.
    5. Click Add role in the dialog box that opens and select the kms.keys.encrypterDercrypter role.

    Run this command:

    yc resource-manager folder add-access-binding <folder_ID> \
   --role kms.keys.encrypterDercrypter \
   --subject serviceAccount:<service_account_ID>

    To assign the service account a role for the folder, use the setAccessBindings REST API method for the ServiceAccount resource or the ServiceAccountService/SetAccessBindings gRPC API call.

Create a secret

Create a secret in Yandex Lockbox and use it to save username-password pairs of users for whom accounts will be created in the Windows OS.

Warning

When choosing a password, make sure to comply with the password security requirements; otherwise, the account will not be created for the user.
The password must:

  • Contain eight or more characters.
  • Not contain the account name.
  • Contain characters from at least three of the following four groups:
    • Latin uppercase letters (A-Z)
    • Latin lowercase letters (a-z)
    • Digits (0-9)
    • Non-alphanumeric characters (!, ?, %, $, #, etc.)
  1. In the management console, select the folder where you want to create a secret.
  2. In the list of services, select Lockbox.
  3. Click Create secret.
  4. In the Name field, enter a name for the secret: win-secret.
  5. In the KMS key field, specify the win-secret-key key.
  6. Under Version:
    • In the Key field, enter the username for Administrator.
    • In the Value, enter the administrator password.
  7. Add more users if needed by clicking Add key/value and entering the username and password for the next user.
  8. Click Create.

  1. Run this command:

    yc lockbox secret create \
   --name win-secret \
   --kms-key-id <key_ID> \
   --payload "[{'key': 'Administrator', 'text_value': '<administrator_password>'},{'key': 'user1', 'text_value': '<user_password>'}]" \
   --cloud-id <cloud_ID> \
   --folder-id <folder_ID>

    Where:

    • --name: Secret name. This is a required parameter.
    • --kms-key-id: ID of the KMS key.
    • --description: Secret description. This is an optional parameter.
    • --payload: Contents of the secret as a YAML or JSON array.
    • --cloud-id: ID of the cloud where you want to create your secret.
    • --folder-id: ID of the folder where you want to create a secret.

If you don't have Terraform, install it and configure the Yandex Cloud provider.

  1. In the configuration file, describe the parameters of the resources you want to create:

    resource "yandex_lockbox_secret" "win_secret" {
   name                = "<secret_name>"
   folder_id           = "<folder_ID>"
   kms_key_id          = "<encryption_key_ID>"
}
resource "yandex_lockbox_secret_version" "win_secret_version" {
  secret_id = yandex_lockbox_secret.win_secret.id
  entries {
    key        = "Administrator"
    text_value = "<administrator_password>"
  }
  entries {
    key        = "user1"
    text_value = "<user_password>"
  }
}

    Where:

    • name: Secret name. This is a required parameter.
    • folder_id: ID of the folder where you want to create a secret. This is an optional parameter.
    • kms_key_id: ID of the Key Management Service encryption key. The specified Key Management Service key is used to encrypt your secret.
    • entries: Contents of the secret.

    Note

    We recommend using yandex_lockbox_secret_version_hashed: it stores values in Terraform state in hashed format. We continue supporting yandex_lockbox_secret_version.

    For more information about yandex_lockbox_secret_version_hashed, see the relevant provider documentation.

    Warning

    To improve security, you should set the password in the configuration file using the environment variable.

  2. Create resources:

    1. In the terminal, change to the folder where you edited the configuration file.

    2. Make sure the configuration file is correct using the command:

      terraform validate

      If the configuration is correct, the following message is returned:

      Success! The configuration is valid.

    3. Run the command:

      terraform plan

      The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.

    4. Apply the configuration changes:

      terraform apply

    5. Confirm the changes: type yes in the terminal and press Enter.

To create a secret, use the create REST API method for the Secret resource or the SecretService/Create gRPC API call.

  1. Assign the lockbox.payloadViewer role to the win-secret-sa service account:

    1. Go to the Access rights tab on the secret page.
    2. Go to the Access bindings tab.
    3. Find the win-secret-sa account in the list and click .
    4. Click Edit roles.
    5. Click Add role in the dialog box that opens and select the lockbox.payloadViewer role.

    Run this command:

    yc resource-manager folder add-access-binding <folder_ID> \
   --role lockbox.payloadViewer \
   --subject serviceAccount:<service_account_ID>

    To assign the service account a role for the folder, use the setAccessBindings REST API method for the ServiceAccount resource or the ServiceAccountService/SetAccessBindings gRPC API call.

Create a VM

Create a VM with the Windows OS having the administrator and user accounts.

  1. Create a file named init.ps1 and save the following code in it:

    #ps1

# logging
Start-Transcript -Path "$ENV:SystemDrive\provision2.txt" -IncludeInvocationHeader -Force
"Bootstrap script started" | Write-Host

# SECRET'S ID:
$SecretID = "<secret_id>"

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
$SecretURL = "https://payload.lockbox.api.cloud.yandex.net/lockbox/v1/secrets/$SecretID/payload"

"Secret ID is $SecretID"
"Payload URL is $SecretURL"

$YCToken = (Invoke-RestMethod -Headers @{'Metadata-Flavor'='Google'} -Uri "http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/token").access_token
if (!$YCToken) {
    throw "Service Account doesn't connected to VM. Please, add Service account with roles lockbox.payloadViewer and kms.key.encryptorDecryptor to VM and try again."
}

# Creating parameters for REST-invokations
$Headers = @{
    Authorization="Bearer $YCToken"
}

$Params = @{
    Uri = $SecretURL
    Method = "GET"
    Headers = $Headers
}

# Getting secret via REST invoke
$Secret = Invoke-RestMethod @Params
$SecretAdministratorPlainTextPassword = $Secret.entries[0].textValue

# inserting value's from terraform
if (-not [string]::IsNullOrEmpty($SecretAdministratorPlainTextPassword)) {
    "Set local administrator password" | Write-Host
    $SecretAdministratorPassword = $SecretAdministratorPlainTextPassword | ConvertTo-SecureString -AsPlainText -Force
    # S-1-5-21domain-500 is a well-known SID for Administrator
    # https://docs.microsoft.com/en-us/troubleshoot/windows-server/identity/security-identifiers-in-windows
    $Administrator = Get-LocalUser | Where-Object -Property "SID" -like "S-1-5-21-*-500"
    $Administrator | Set-LocalUser -Password $SecretAdministratorPassword
}

# Creating new users if any
if($Secret.entries.count -gt 1) {
    foreach($User in $Secret.entries[1..($Secret.entries.count-1)]){
        $SecretUserPassword = $User.textValue | ConvertTo-SecureString -AsPlainText -Force
        New-LocalUser -Name $User.key -Password $SecretUserPassword -FullName $User.key
        Add-LocalGroupMember -Group Users -Member $User.key
        Add-LocalGroupMember -Group "Remote Desktop Users" -Member $User.key
    }
}

"Bootstrap script ended" | Write-Host

  2. In the init.ps1 file, replace the <secret_id> placeholder with the real ID of the secret where you saved the user accounts.

  3. Create a VM:

    1. In the management console, open the folder to create your VM in.
    2. At the top right, click Create resource.
    3. In the list that opens, select Virtual machine instance.
    4. Under General information:
      • Enter the VM name, e.g., win-test.
      • Select an availability zone to place your VM in.
    5. Under Boot disk image, select the image with the Windows OS.
    6. Under Access, specify the data for access to the VM:
    7. Under Metadata:
      • In the field with the Key placeholder, enter user-data.
      • In the field with the Value placeholder, paste the contents of the init.ps1 file.
    8. Click Create VM.

    Run this command:

    yc compute instance create --name win-test --hostname windows10 --zone ru-central1-a --create-boot-disk image-id=<imade_id> --cores 2 --core-fraction 100 --memory 4 --metadata-from-file user-data=init.ps1  --network-interface subnet-name=<subnet_name>,nat-ip-version=ipv4 --service-account-name win-test-sa --platform standard-v3

    Where:

    • imade_id: ID of the image with the Windows OS.
    • subnet_name: Subnet name in the folder where you want to place the VM.

Log in to Windows

To check that the data from the secret was successfully used to create users, log in to the VM's OS:

  1. In the management console, select the folder the VM belongs to.

  2. Select Compute Cloud.

  3. Select the win-test VM.

  4. Go to the Serial console tab.

  5. Under Serial consoleAdvanced settings, select COM2 and click Connect. The command line will prompt you to enter commands:

    SAC>

  6. View the list of open channels:

    SAC>ch
Channel List

(Use "ch -?" for information on using channels)

# Status  Channel Name
0 (AV)    SAC
1 (AV)    Cmd0001

  7. To switch to a channel, press ESC+TAB or run the command:

    SAC>ch -sn Cmd0001
Name:                  Cmd0001
Description:           Command
Type:                  VT-UTF8
Channel GUID:          e203fb79-d80d-11ea-87e3-c2679e14957d
Application Type GUID: 63d02271-8aa4-11d5-bccf-00b0d014a2d0

Press <esc><tab> for next channel.
Press <esc><tab>0 to return to the SAC channel.
Use any other key to view this channel.

  8. Press Enter and specify the following in the given order:

    • Username.
    • Domain if the domain account is used for logging in. Otherwise, enter the hostname or leave empty.
    • Password.
    Please enter login credentials.
Username: Administrator
Domain  :
Password: ***************

  9. If you log in successfully, an instance of the command line interpreter will start:

    C:\Windows\system32>

    If you log in successfully, it means that the data from the secret was used to create the VM.

How to delete the resources you created

To stop paying for the resources you created:

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