PowerShell - Invoke Command on Remote Machines/Computers - powershell

Question

There's plenty of forums/material regarding the subject line, but cannot seem to get an answer for my problem.
I'm trying to execute a script from the main server (SRV01) that will clean the temp folders on the secondary servers (SRV02, SRV03).
Here is the script:
#Set the machines on the network to run the script on
$VDST = #("SRV02", "SRV03")
#Folder locations to clean out
$TempFolder = #("C:\Windows\Temp\*", "C:\Documents and Settings\*\Local Settings\temp\*")
#This function actually performs the clean up operation
Function executeCleanUp
{
$TempFolder = $args[0]
$machineNames = $args[2]
ForEach($machine in $machineNames){
Get-PSSession -ComputerName $machine | Format-Table -Property ComputerName, InstanceID
Write-Host 'Starting Clean Up...'
#Loop through the sub folders in the registry location
ForEach($folderLocation in $TempFolder)
{
$StrInput = 'Remove-Item -Path ' + $folderLocation + ' -Force -Recurse -ErrorAction SilentlyContinue'
$action = New-ScheduledTaskAction -Execute 'PowerShell.exe' -Argument $StrInput
Register-ScheduledTask -Action $action -TaskName "CleanUp"
Start-ScheduledTask -TaskName "CleanUp"
Unregister-ScheduledTask -TaskName "CleanUp" -Confirm:$false -ErrorAction SilentlyContinue
}
}
#Execute Script on specified machines - provided in array above
Invoke-Command -ComputerName $VDST -ScriptBlock ${function:executeCleanUp} -ArgumentList $TempFolder, $VDST
After running the above, I get the error:
A specified logon session does not exist
So, I came across a forum where it was suggested to do the following:
#Remote Server (VDI)
Enable-WSManCredSSP -Role server
#Expected Output
#This computer is configured to receive credentials from a remote client computer.
#Local Machine
Enable-WSManCredSSP -Role Client -DelegatedCredentials 'SRV01'
#Expected Output
#The machine is configured to allow delegating fresh credentials to the following target(s): wsman/SRV01.
#Local Machine
#Open gpedit.msc
#Browse to Computer Configuration > Administrative Templates > System > Credentials Delegation.
#Double-click "Allow delegating fresh credentials with NTLM-only Server Authentication"
#Enable the setting
#Add the build server to the server list as WSMAN/BuildServerName.
#Example Execution:
#Invoke-Command -ComputerName <REMOTE_COMPUTER_NAME> -Authentication CredSSP -Credential <USERNAME> -ScriptBlock { #code}
I've done all this, but now I get the error:
A computer policy does not allow the delegation of the user
credentials to the target computer
Also, I am assuming the line
WSMAN/BuildServerName
should be written
WSMAN/SRV02

Answer 1

The 2 hop authentication issue came up because you are trying to list remote sessions with in your remote session
Get-PSSession -ComputerName $machine | Format-Table -Property ComputerName, InstanceID
If you just want to clear some files on the remote servers the code below should work with no need for CredSPP.
Setting -ErrorAction SilentlyContinue will make trouble shooting difficult, It's easier to check if the file exists before you try to delete it.
$TempFolder = $args[0]
$ComputerArray = "SRV02","SRV03"
$ScriptBlock =
{
foreach ($Folder in $TempFolders)
{
if (Test-Path -Path $TempFolder)
{
Remove-Item -Path $Folder -force
}
}
}
Invoke-Command -ComputerName $ComputerArray -ScriptBlock $ScriptBlock -ArgumentList $TempFolder
Wrong answer:
Your issue is two hop authentication.
You can't nest remote sessions with default windows settings.
While this would not be considered to be best practice, you can enable CredSSP to bypass the problem.
https://learn.microsoft.com/en-us/windows/win32/secauthn/credential-security-support-provider
https://learn.microsoft.com/en-us/powershell/module/microsoft.wsman.management/enable-wsmancredssp?view=powershell-7
Could you either log on to SVR01 to run the script or run the script against the target machines from your own computer?