Windows Sandbox configuration

Windows Sandbox supports simple configuration files, which provide a minimal set of customization parameters for Sandbox. This feature can be used with Windows 10 build 18342 or later.

Windows Sandbox configuration files are formatted as XML and are associated with Sandbox via the .wsb file extension. To use a configuration file, double-click it to open it in the sandbox. You can also invoke it via the command line as shown here:

C:\Temp> MyConfigFile.wsb

A configuration file enables the user to control the following aspects of Windows Sandbox:

  • vGPU (virtualized GPU): Enable or disable the virtualized GPU. If vGPU is disabled, the sandbox will use Windows Advanced Rasterization Platform (WARP).
  • Networking: Enable or disable network access within the sandbox.
  • Mapped folders: Share folders from the host with read or write permissions. Note that exposing host directories may allow malicious software to affect the system or steal data.
  • Logon command: A command that's executed when Windows Sandbox starts.
  • Audio input: Shares the host's microphone input into the sandbox.
  • Video input: Shares the host's webcam input into the sandbox.
  • Protected client: Places increased security settings on the RDP session to the sandbox.
  • Printer redirection: Shares printers from the host into the sandbox.
  • Clipboard redirection: Shares the host clipboard with the sandbox so that text and files can be pasted back and forth.
  • Memory in MB: The amount of memory, in megabytes, to assign to the sandbox.

Keywords, values, and limits

vGPU: Enables or disables GPU sharing.

<vGPU>value</vGPU>

Supported values:

  • Enable: Enables vGPU support in the sandbox.
  • Disable: Disables vGPU support in the sandbox. If this value is set, the sandbox will use software rendering, which may be slower than virtualized GPU.
  • Default This is the default value for vGPU support. Currently this means vGPU is disabled.

Note

Enabling virtualized GPU can potentially increase the attack surface of the sandbox.

Networking: Enables or disables networking in the sandbox. You can disable network access to decrease the attack surface exposed by the sandbox.

<Networking>value</Networking>

Supported values:

  • Disable: Disables networking in the sandbox.
  • Default: This is the default value for networking support. This value enables networking by creating a virtual switch on the host and connects the sandbox to it via a virtual NIC.

Note

Enabling networking can expose untrusted applications to the internal network.

Mapped folders: An array of folders, each representing a location on the host machine that will be shared into the sandbox at the specified path. At this time, relative paths are not supported. If no path is specified, the folder will be mapped to the container user's desktop.

<MappedFolders>
  <MappedFolder> 
    <HostFolder>absolute path to the host folder</HostFolder> 
    <SandboxFolder>absolute path to the sandbox folder</SandboxFolder> 
    <ReadOnly>value</ReadOnly> 
  </MappedFolder>
  <MappedFolder>  
    ...
  </MappedFolder>
</MappedFolders>

HostFolder: Specifies the folder on the host machine to share into the sandbox. Note that the folder must already exist on the host, or the container will fail to start.

SandboxFolder: Specifies the destination in the sandbox to map the folder to. If the folder doesn't exist, it will be created. If no sandbox folder is specified, the folder will be mapped to the container desktop.

ReadOnly: If true, enforces read-only access to the shared folder from within the container. Supported values: true/false. Defaults to false.

Note

Files and folders mapped in from the host can be compromised by apps in the sandbox or potentially affect the host.

Logon command: Specifies a single command that will be invoked automatically after the sandbox logs on. Apps in the sandbox are run under the container user account.

<LogonCommand>
  <Command>command to be invoked</Command>
</LogonCommand>

Command: A path to an executable or script inside the container that will be executed after login.

Note

Although very simple commands will work (such as launching an executable or script), more complicated scenarios involving multiple steps should be placed into a script file. This script file may be mapped into the container via a shared folder, and then executed via the LogonCommand directive.

Audio input: Enables or disables audio input to the sandbox.

<AudioInput>value</AudioInput>

Supported values:

  • Enable: Enables audio input in the sandbox. If this value is set, the sandbox will be able to receive audio input from the user. Applications that use a microphone may require this capability.
  • Disable: Disables audio input in the sandbox. If this value is set, the sandbox can't receive audio input from the user. Applications that use a microphone may not function properly with this setting.
  • Default: This is the default value for audio input support. Currently this means audio input is enabled.

Note

There may be security implications of exposing host audio input to the container.

Video input: Enables or disables video input to the sandbox.

<VideoInput>value</VideoInput>

Supported values:

  • Enable: Enables video input in the sandbox.
  • Disable: Disables video input in the sandbox. Applications that use video input may not function properly in the sandbox.
  • Default: This is the default value for video input support. Currently this means video input is disabled. Applications that use video input may not function properly in the sandbox.

Note

There may be security implications of exposing host video input to the container.

Protected client: Applies additional security settings to the sandbox Remote Desktop client, decreasing its attack surface.

<ProtectedClient>value</ProtectedClient>

Supported values:

  • Enable: Runs Windows sandbox in Protected Client mode. If this value is set, the sandbox runs with extra security mitigations enabled.
  • Disable: Runs the sandbox in standard mode without extra security mitigations.
  • Default: This is the default value for Protected Client mode. Currently, this means the sandbox doesn't run in Protected Client mode.

Note

This setting may restrict the user's ability to copy/paste files in and out of the sandbox.

Printer redirection: Enables or disables printer sharing from the host into the sandbox.

<PrinterRedirection>value</PrinterRedirection>

Supported values:

  • Enable: Enables sharing of host printers into the sandbox.
  • Disable: Disables printer redirection in the sandbox. If this value is set, the sandbox can't view printers from the host.
  • Default: This is the default value for printer redirection support. Currently this means printer redirection is disabled.

Clipboard redirection: Enables or disables sharing of the host clipboard with the sandbox.

<ClipboardRedirection>value</ClipboardRedirection>

Supported values:

  • Disable: Disables clipboard redirection in the sandbox. If this value is set, copy/paste in and out of the sandbox will be restricted.
  • Default: This is the default value for clipboard redirection. Currently copy/paste between the host and sandbox are permitted under Default.

Memory in MB: Specifies the amount of memory that the sandbox can use in megabytes (MB).

<MemoryInMB>value</MemoryInMB>

If the memory value specified is insufficient to boot a sandbox, it will be automatically increased to the required minimum amount.

Example 1
The following config file can be used to easily test downloaded files inside the sandbox. To achieve this, networking and vGPU are disabled, and the sandbox is allowed read-only access to the shared downloads folder. For convenience, the logon command opens the downloads folder inside the sandbox when it's started.

Downloads.wsb

<Configuration>
  <VGpu>Disable</VGpu>
  <Networking>Disable</Networking>
  <MappedFolders>
    <MappedFolder>
      <HostFolder>C:\Users\Public\Downloads</HostFolder>
      <SandboxFolder>C:\Users\WDAGUtilityAccount\Downloads</SandboxFolder>
      <ReadOnly>true</ReadOnly>
    </MappedFolder>
  </MappedFolders>
  <LogonCommand>
    <Command>explorer.exe C:\users\WDAGUtilityAccount\Downloads</Command>
  </LogonCommand>
</Configuration>

Example 2

The following config file installs Visual Studio Code in the sandbox, which requires a slightly more complicated LogonCommand setup.

Two folders are mapped into the sandbox; the first (SandboxScripts) contains VSCodeInstall.cmd, which will install and run Visual Studio Code. The second folder (CodingProjects) is assumed to contain project files that the developer wants to modify using Visual Studio Code.

With the Visual Studio Code installer script already mapped into the sandbox, the LogonCommand can reference it.

VSCodeInstall.cmd

REM Download Visual Studio Code
curl -L "https://update.code.visualstudio.com/latest/win32-x64-user/stable" --output C:\users\WDAGUtilityAccount\Desktop\vscode.exe

REM Install and run Visual Studio Code
C:\users\WDAGUtilityAccount\Desktop\vscode.exe /verysilent /suppressmsgboxes

VSCode.wsb

<Configuration>
  <MappedFolders>
    <MappedFolder>
      <HostFolder>C:\SandboxScripts</HostFolder>
      <ReadOnly>true</ReadOnly>
    </MappedFolder>
    <MappedFolder>
      <HostFolder>C:\CodingProjects</HostFolder>
      <ReadOnly>false</ReadOnly>
    </MappedFolder>
  </MappedFolders>
  <LogonCommand>
    <Command>C:\Users\WDAGUtilityAccount\Desktop\SandboxScripts\VSCodeInstall.cmd</Command>
  </LogonCommand>
</Configuration>