How to run a process as non-admin from an elevated PowerShell console?

Question

Maybe there is a way to do it with Start-Process cmdlet that I cannot find? The other related Q/A's I found on StackOverflow such as this, this and this all give a solution to do this with a custom C# code. My question is specifically, is there any straightforward way to do this in PowerShell? i.e. you are in an elevated PS console and want to run a process as non-admin.

Answer 1

You can specify the TrustLevel with runas.exe, effectively running "restricted"

runas /trustlevel:0x20000 "powershell.exe -command 'whoami /groups |clip'"

You should see in the output from whoami that the Administrators group in your token is marked as "Used for Deny only"

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Answer 2

When you dig into this problem, as mentioned by the linked tasks, there is no way to run a UAC "non" elevated process from a elevated process. Since this is exactly what I required and the runas solution didn't work for me I converted the code workaround supplied by Microsoft to use a scheduled task to Start a "non" elevated process.

Example of running powershell.exe as a "non" elevated process from a elevated powershell prompt:

$apppath = "powershell.exe"
$taskname = "Launch $apppath"
$action = New-ScheduledTaskAction -Execute $apppath
$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date)
Register-ScheduledTask -Action $action -Trigger $trigger -TaskName $taskname | Out-Null
Start-ScheduledTask -TaskName $taskname
Start-Sleep -s 1
Unregister-ScheduledTask -TaskName $taskname -Confirm:$false

The above powershell commands only work on Windows Server 2012 / Windows 8 and greater only.

Or you can use the SCHTASKS.EXE application instead to cover most versions of windows:

$apppath = "powershell.exe"
$taskname = "Launch $apppath"
schtasks /create /SC ONCE /ST 23:59 /TN $taskname /TR $apppath
schtasks /run /tn $taskname
Start-Sleep -s 1
schtasks /delete /tn $taskname /F