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Action a PS Encoded Script

The proper way to Action a PowerShell script is to either convert it to a ONE LINER, or simply Encode the contents. In this example, I want to create a Scheduled Task with the following results

  • Export third party drivers to C:\Exported Drivers

  • Log to C:\Windows\Logs\Drivers

  • Run as SYSTEM for Standard Users

Action Script

The following script is what would be run to export the drivers to C:\ExportedDrivers and to write a Transcript to C:\Windows\Logs\Drivers

$TaskName = 'Export-WindowsDriverOnline'
#======================================================================================
#   Logs
#======================================================================================
$TaskLogs = "$env:SystemRoot\Logs\Drivers"
if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
$TaskLogName = "$((Get-Date).ToString('yyyy-MM-dd-HHmmss'))-$TaskName.log"
Start-Transcript -Path (Join-Path $TaskLogs $TaskLogName)
#======================================================================================
#   Main
#======================================================================================
#if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
Export-WindowsDriver -Online -Destination $env:SystemDrive\ExportedDrivers
#======================================================================================
#   Complete
#======================================================================================
Stop-Transcript

Encoding the Command

Its easy enough to put the script into a Variable $TaskScript and convert the Variable to $EncodedCommand

#======================================================================================
#   Script
$TaskScript = @'
$TaskName = 'Export-WindowsDriverOnline'
#======================================================================================
#   Logs
#======================================================================================
$TaskLogs = "$env:SystemRoot\Logs\Drivers"
if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
$TaskLogName = "$((Get-Date).ToString('yyyy-MM-dd-HHmmss'))-$TaskName.log"
Start-Transcript -Path (Join-Path $TaskLogs $TaskLogName)
#======================================================================================
#   Main
#======================================================================================
#if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
Export-WindowsDriver -Online -Destination $env:SystemDrive\ExportedDrivers
#======================================================================================
#   Complete
#======================================================================================
Stop-Transcript
'@
#======================================================================================
#   Encode the Script
$EncodedCommand = [System.Convert]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes($TaskScript))

Splat the Action

The following example is how to Action the $EncodedCommand in the Scheduled Task

$Action = @{
    Execute = 'powershell.exe'
    Argument = "-ExecutionPolicy ByPass -EncodedCommand $EncodedCommand"
}

Full Script

Once I have that information, I can complete the script for creating my Scheduled Task

#======================================================================================
#   Task Properties
$TaskName = 'Export-WindowsDriverOnline'
$TaskPath = '\Corporate\Drivers'
$Description = @"
Exports third party drivers to $env:SystemDrive\ExportedDrivers
Transcripts are stored in $env:SystemRoot\Logs\Drivers  
Runs as SYSTEM and does not display any progress or results  
PowerShell Encoded Script  
Version 21.1.19
"@
#======================================================================================
#   Script
$TaskScript = @'
$TaskName = 'Export-WindowsDriverOnline'
#======================================================================================
#   Logs
#======================================================================================
$TaskLogs = "$env:SystemRoot\Logs\Drivers"
if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
$TaskLogName = "$((Get-Date).ToString('yyyy-MM-dd-HHmmss'))-$TaskName.log"
Start-Transcript -Path (Join-Path $TaskLogs $TaskLogName)
#======================================================================================
#   Main
#======================================================================================
#if (!(Test-Path $TaskLogs)) {New-Item $TaskLogs -ItemType Directory -Force | Out-Null}
Export-WindowsDriver -Online -Destination $env:SystemDrive\ExportedDrivers
#======================================================================================
#   Complete
#======================================================================================
Stop-Transcript
'@
#======================================================================================
#   Encode the Script
$EncodedCommand = [System.Convert]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes($TaskScript))
#======================================================================================
#   Splat the Task
$Action = @{
    Execute = 'powershell.exe'
    Argument = "-ExecutionPolicy ByPass -EncodedCommand $EncodedCommand"
}
$Principal = @{
    UserId = 'SYSTEM'
    RunLevel = 'Highest'
}
$Settings = @{
    AllowStartIfOnBatteries = $true
    Compatibility = 'Win8'
    MultipleInstances = 'Parallel'
    ExecutionTimeLimit = (New-TimeSpan -Minutes 60)
}
$ScheduledTask = @{
    Action = New-ScheduledTaskAction @Action
    Principal = New-ScheduledTaskPrincipal @Principal
    Settings = New-ScheduledTaskSettingsSet @Settings
    Description = $Description
}
#======================================================================================
#   Build the Task
New-ScheduledTask @ScheduledTask | Register-ScheduledTask -TaskName $TaskName -TaskPath $TaskPath -Force
#======================================================================================
#   Apply Authenticated User Permissions
$Scheduler = New-Object -ComObject "Schedule.Service"
$Scheduler.Connect()
$GetTask = $Scheduler.GetFolder($TaskPath).GetTask($TaskName)
$GetSecurityDescriptor = $GetTask.GetSecurityDescriptor(0xF)
if ($GetSecurityDescriptor -notmatch 'A;;0x1200a9;;;AU') {
    $GetSecurityDescriptor = $GetSecurityDescriptor + '(A;;GRGX;;;AU)'
    $GetTask.SetSecurityDescriptor($GetSecurityDescriptor, 0)
}

Results

The Task gets created properly with the Encoded script

Running the Task works flawlessly in exporting the drivers

And everything is logged in the PowerShell Transcript, including the Encoded Script

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