Running PowerShell as another user, and launching a script

Powershell Problem Overview

I won't get into all the details of why I need this, but users must be able to launch PowerShell as a service account and when PowerShell loads it needs to run a script. I already can launch PowerShell with the stored credentials (stored as a secure string), but for the life of me I cannot get the script (located in $args) to run. I have tried a variety of things, and below is where I am currently. Any help would be greatly appreciated.

$user = "domain\service.account" 
$pwd1 = "big long huge string of characters"
$pwd = ($pwd1 | ConvertTo-SecureString)
$Credential = New-Object System.Management.Automation.PSCredential $user, $pwd
$args = "\\domain.local\location\location\location\Script\script.ps1"
Start-Process powershell.exe -Credential $Credential -ArgumentList ("-file $args")

Powershell Solutions

Solution 1 - Powershell

You can open a new powershell window under a specified user credential like this:

start powershell -credential ""

Solution 2 - Powershell

I found this worked for me.

$username = 'user'
$password = 'password'

$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
$credential = New-Object System.Management.Automation.PSCredential $username, $securePassword
Start-Process Notepad.exe -Credential $credential

Updated: changed to using single quotes to avoid special character issues noted by Paddy.

Solution 3 - Powershell

Here's also nice way to achieve this via UI.

Right click on PowerShell icon when on task bar
Shift + right click on Windows PowerShell
"Run as different user"

Solution 4 - Powershell

Try adding the RunAs option to your Start-Process

Start-Process powershell.exe -Credential $Credential -Verb RunAs -ArgumentList ("-file $args")

Solution 5 - Powershell

In windows server 2012 or 2016 you can search for Windows PowerShell and then "Pin to Start". After this you will see "Run as different user" option on a right click on the start page tiles.

Solution 6 - Powershell

You can get a credential popup that will get the username and password as strings like this:

#Get credentials
$credential = Get-Credential
$username = $credential.Username
$password = $credential.GetNetworkCredential().Password

Then you can use in your script the variables $username and $password

Solution 7 - Powershell

This command works for me:

Start-Process powershell.exe -Credential $Credential -ArgumentList "-file $FILE"

If the $FILE is on network, make sure the run-as user can access the file.

Script

I just created a script to make it easier for automation:

 <#

.SYNOPSIS

Run command as another user.

.DESCRIPTION

Run batch or PowerShell command as another user.

.PARAMETER Command

The batch command you'd like to execute as another user.

.PARAMETER ScriptBlock

The PowerShell command you'd like to execute as another user.

.PARAMETER Username

Run the command as what user.

.PARAMETER Password

Password of the user.

.PARAMETER Credential

PowerShell credential of the user, it can be generated by `Get-Credential`.

.PARAMETER Wait

Wait command to complete or not.
Command output would not be displayed if it is not specified.

#>

Param (
    [Parameter(Mandatory = $true, ParameterSetName = "bat-user-password")]
    [Parameter(Mandatory = $true, ParameterSetName = "bat-credential")]
    [ValidateNotNullOrEmpty()]
    [String]
    $Command,

    [Parameter(Mandatory = $true, ParameterSetName = "ps-user-password")]
    [Parameter(Mandatory = $true, ParameterSetName = "ps-credential")]
    [ScriptBlock]
    $ScriptBlock,

    [Parameter(Mandatory = $true, ParameterSetName = "bat-user-password")]
    [Parameter(Mandatory = $true, ParameterSetName = "ps-user-password")]
    [ValidateNotNullOrEmpty()]
    [String]
    $Username,

    [Parameter(Mandatory = $true, ParameterSetName = "bat-user-password")]
    [Parameter(Mandatory = $true, ParameterSetName = "ps-user-password")]
    [ValidateNotNullOrEmpty()]
    [String]
    $Password,

    [Parameter(Mandatory = $true, ParameterSetName = "bat-credential")]
    [Parameter(Mandatory = $true, ParameterSetName = "ps-credential")]
    [PSCredential]
    $Credential,

    [Switch]
    $Wait
)

$IsCurrentAdminUser = $([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] 'Administrator')

# Find a dir that every user have full access to
$TempDir = "$env:SystemDrive\Users\Public\run_as"
if (-not (Test-Path -Path $TempDir)) {
    $null = New-Item -Path $TempDir -ItemType Directory
    attrib +h $TempDir
}

# Generate a uniq id for problem tracking
$ExecId = Get-Random -Maximum 99999999 -Minimum 10000000

# Temp files
$UserScriptPrefix = "$TempDir\$ExecId-UserScript"
$UserStdOut = "$TempDir\$ExecId-UserStdOut.log"
$UserErrOut = "$TempDir\$ExecId-UserErrOut.log"
$WaitFile = "$TempDir\$ExecId-Running"

$ExecScript = "$TempDir\$ExecId-Exec.ps1"
$CmdToExec = "Start-Process"

if ($PsCmdlet.ParameterSetName.StartsWith('bat')) {
    $UserScript = $UserScriptPrefix + '.bat'
    $Command |Out-File -FilePath $UserScript -Encoding ascii

    $CmdToExec += " cmd.exe -ArgumentList '/c $UserScript'"
} elseif ($PsCmdlet.ParameterSetName.StartsWith('ps')) {
    $UserScript = $UserScriptPrefix + '.ps1'
    $ScriptBlock |Out-File -FilePath $UserScript -Encoding ascii

    $CmdToExec += " PowerShell.exe -ArgumentList '-file $UserScript'"
}

if ($PsCmdlet.ParameterSetName.EndsWith('user-password')) {
    $SecPassword = ConvertTo-SecureString -String $Password -AsPlainText -Force
    $Credential = New-Object -TypeName System.Management.Automation.PSCredential ($Username, $SecPassword)
}

$CmdToExec += " -WorkingDirectory $env:SystemDrive\"

if ($Wait) {
    # Redirect output only if -Wait flag is set
    $CmdToExec += " -RedirectStandardError $UserErrOut"
    $CmdToExec += " -RedirectStandardOutput $UserStdOut"

    if ($IsCurrentAdminUser) {
        # -Wait parameter of Start-Process only works with admin users
        # Using it with non-admin users will get an "Access is denied" error
        $CmdToExec += " -Wait"
    }
}

$script = @'
Param($Cred)
"" | Out-File -FilePath {0}

try {{
    {1} -Credential $Cred
}} catch {{
    Write-Host $_
}} finally {{
    Remove-Item -Path {0} -Force -Confirm:$false
}}
'@ -f $WaitFile, $CmdToExec

$Script |Out-File -FilePath $ExecScript -Encoding ascii

try {
    & $ExecScript -Cred $Credential
} catch {
    Write-Host $_
} finally {
    if ($Wait) {
        if (-not $IsCurrentAdminUser) {
            # Impelment the wait by file monitoring for non-admin users
            do {
                Start-Sleep -Seconds 1
            } while (Test-Path -Path $WaitFile)
    
            # Wait output are write to files completely
            Start-Sleep -Seconds 1
        }

        # Read command output from files
        if (Test-Path -Path $UserStdOut) {
            Get-Content -Path $UserStdOut
        }

        if (Test-Path -Path $UserErrOut) {
            Get-Content -Path $UserErrOut
        }
    }

    Remove-Item -Path "$TempDir\$ExecId-*" -Force -Confirm:$false -ErrorAction SilentlyContinue
}

Copy the content and save to a *.ps1 file, like run_as.ps1.

Document

Show build-in doucment:

PS C:\> Get-Help C:\run_as.ps1 -detailed

NAME
    C:\run_as.ps1

SYNOPSIS
    Run command as another user.


SYNTAX
    C:\run_as.ps1 -Command <String> -Credential <PSCredential> [-Wait] [<CommonParameters>]

    C:\run_as.ps1 -Command <String> -Username <String> -Password <String> [-Wait] [<CommonParameters>]

    C:\run_as.ps1 -ScriptBlock <ScriptBlock> -Credential <PSCredential> [-Wait] [<CommonParameters>]

    C:\run_as.ps1 -ScriptBlock <ScriptBlock> -Username <String> -Password <String> [-Wait] [<CommonParameters>]


DESCRIPTION
    Run batch or PowerShell command as another user.


PARAMETERS
......

Examples

01

Current user is administrator, run batch command as user01 with password

Note: Please DO NOT use plain password in production environment. You can use it for testing. In a production environment, you can use -Credential option instead.

PS C:\> whoami
test-win-1\administrator
PS C:\> .\run_as.ps1 -Command 'whoami' -Username 'user01' -Password 'password1'
PS C:\> 
PS C:\> # Add -Wait to get command output
PS C:\> .\run_as.ps1 -Command 'whoami' -Username 'user01' -Password 'password1' -Wait

C:\>whoami
test-win-1\user01
PS C:\> 
PS C:\> # Add '@' to batch command to avoid the header lines
PS C:\> .\run_as.ps1 -Command '@whoami' -Username 'user01' -Password 'password1' -Wait
test-win-1\user01
PS C:\>

02

Current user is administrator, run PowerShell command as user02 with password