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Set-SecureBootUEFI

  • Reference
Module:
SecureBoot

Sets the Secure Boot-related UEFI variables.

Syntax

Set-SecureBootUEFI
   -Name <String>
   [-ContentFilePath <String>]
   [-SignedFilePath <String>]
   -Time <String>
   [-AppendWrite]
   [-OutputFilePath <String>]
   [<CommonParameters>]
Set-SecureBootUEFI
   -Name <String>
   [-Content <Byte[]>]
   [-SignedFilePath <String>]
   -Time <String>
   [-AppendWrite]
   [-OutputFilePath <String>]
   [<CommonParameters>]

Description

The Set-SecureBootUEFI cmdlet takes a formatted content object that is created by running the Format-SecureBootUEFI cmdlet and a signed file, combines the two and then attempts to set the package in one of the Secure Boot variables. The supported Secure Boot variables include Platform Key (PK), Key Exchange Key (KEK), Signature Database (DB), and Forbidden Signature Database (DBX).

If successful, this cmdlet returns a UEFIEnvironmentVariable object. Otherwise, it displays an error.

This cmdlet runs on both UEFI and BIOS (non-UEFI) computers. If the computer does not support Secure Boot or is a non-UEFI computer, this cmdlet displays the following:

Cmdlet not supported on this platform.

If you do not run Windows PowerShell® in administrator mode, this cmdlet displays the following:

Unable to set proper privileges. Access was denied.

If you supply a signed file to this cmdlet that is not valid, this cmdlet displays the following:

Incorrect authentication data.

Examples

Example 1: Set the DBX UEFI variable

PS C:\> $ObjectFromFormat = ( Format-SecureBootUEFI -Name DBX -SignatureOwner 12345678-1234-1234-1234-123456789abc -Algorithm SHA256 -Hash 0011223344556677889900112233445566778899001122334455667788990011 -SignableFilePath GeneratedFileToSign.bin -Time 2011-11-01T13:30:00Z -AppendWrite ) 
PS C:\> .\signtool.exe sign /fd sha256 /p7 .\ /p7co 1.2.840.113549.1.7.1 /p7ce DetachedSignedData /a /f PrivateKey.pfx GeneratedFileToSign.bin
PS C:\> $ObjectFromFormat | Set-SecureBootUEFI -SignedFilePath GeneratedFileToSign.bin.p7
Name       : dbx 
Bytes      : {161, 89, 192, 165...} 
Attributes : NON VOLATILE 
             BOOTSERVICE ACCESS 
             RUNTIME ACCESS 
             TIME BASED AUTHENTICATED WRITE ACCESS

This example sets the information obtained from the Format-SecureBootUEFI cmdlet to the DBX UEFI variable.

The first command supplies a path to the signed package to be authenticated. The file named GeneratedFileToSign.bin is a digest created by the Format-SecureBootUEFI cmdlet that needs to be signed according to the UEFI specification.

The second command runs the SignTool.exe tool from the current directory to sign the digest. The SignTool.exe tool can be downloaded from Windows Software Development Kit (SDK) for Windows 8 on MSDN.

The third command sets the information.

Example 2: Set the DBX UEFI variable by using a signed package

PS C:\> Set-SecureBootUEFI -ContentFilePath FormattedVariable.bin -SignedFilePath GeneratedFileToSign.bin.p7
Name       : dbx 
Bytes      : {161, 89, 192, 165...} 
Attributes : NON VOLATILE 
             BOOTSERVICE ACCESS 
             RUNTIME ACCESS 
             TIME BASED AUTHENTICATED WRITE ACCESS

This command sets the formatted data that was written to file FormattedVariable.bin to the DBX UEFI variable. This cmdlet supplies a path to the signed package to be authenticated.

Example 3: Set the DBX UEFI variable by using unsigned data

PS C:\> $objectFromFormat = ( Format-SecureBootUEFI -Name DB -SignatureOwner 12345678-1234-1234-1234-123456789abc -Time 2011-11-01T13:30:00Z -CertificateFilePath db.cer -FormatWithCert )
PS C:\> $objectFromFormat | Set-SecureBootUEFI
Name       : db 
Bytes      : {161, 89, 192, 165...} 
Attributes : NON VOLATILE 
             BOOTSERVICE ACCESS 
             RUNTIME ACCESS 
             TIME BASED AUTHENTICATED WRITE ACCESS

This example creates formatted data that is not signed and sets the unsigned data into the UEFI variable named db.

Parameters

-AppendWrite

Indicates that the contents of the current variable are appended instead of overwritten.

Type:SwitchParameter
Aliases:append
Position:Named
Default value:None
Required:False
Accept pipeline input:True
Accept wildcard characters:False

-Content

Specifies the byte contents of the variable that is being set.

Type:Byte[]
Position:Named
Default value:None
Required:False
Accept pipeline input:True
Accept wildcard characters:False

-ContentFilePath

Specifies the file that contains the contents that is being set to the environment variable.

If you specify only the name, the file must be in the current working directory. Otherwise, specify the full path of the file.

Type:String
Aliases:f
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Name

Specifies the name of the UEFI environment variable. The acceptable values for this parameter are: PK, KEK, DB, and DBX.

Type:String
Aliases:n
Accepted values:PK, KEK, db, dbx
Position:Named
Default value:None
Required:True
Accept pipeline input:True
Accept wildcard characters:False

-OutputFilePath

Specifies the name of the file created that contains the contents of what is set. If you specify this parameter, instead of setting the variable, the cmdlet stores the contents in this file.

The file is created in the specified path location.

Type:String
Aliases:of
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-SignedFilePath

Specifies the signed data that is paired with the contents that are being set to the environment variable.

If you specify only the name, the file must be in the current working directory. Otherwise, specify the full path of the file.

Type:String
Aliases:s
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Time

Specifies the timestamp that is used in the signature. Format this value as follows so that it is accepted as a DateTime object:

"2011-11-01T13:30:00Z"

Type:String
Aliases:t
Position:Named
Default value:None
Required:True
Accept pipeline input:True
Accept wildcard characters:False

Inputs

Microsoft.SecureBoot.Commands.UEFIFormattedVariable

This command accepts a UEFIFormattedVariable object that contains the information for the Name, Time, Content, and AppendWrite parameters.

Outputs

Microsoft.SecureBoot.Commands.UEFIEnvironmentVariable

This cmdlet returns a UEFIEnvironmentVariable object that contains the following properties:

  • Name
  • Guid
  • Bytes
  • Attributes