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powershell with encoded command from windows task scheduler help

Posted on 2014-11-23
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Last Modified: 2015-04-16
I need a PowerShell v2.0 script that will upload files to an FTP site.

The behavior is that I need to run this once / hour via Windows Task scheduler on a Windows 2003 system (hence the PowerShell 2.0). Next year I'll probably have to move to a Windows 2012 server and so I'll appreciate a script that also runs on PowerShell v4.0

I need a script that will take a username and password as command-line parameters and upload files from a directory to an ftp site which require a username and password that are passed to it on an encoded command line just like this which works from the Windows Task scheduler on Windows 2003.

This is the tricky part. We can't have username and password sitting unencrypted in files or code. It needs to be encrypted.

I've seen examples of encrypting data in files, but I really want the data encrypted on the command line to the script so that I'm not creating and managing multiple files. I've seen the encoded command capability via a site that look like:

 powershell.exe -EncodedCommand DQAKAA0ACgAJACQAcABhAHIAYQBtAHMAIAA9ACAARwBlAHQALQBDAG8AbgB0AGUAbgB0ACAAJABlAG4AdgA6AFQARQBNAFAAXABwAGEAcgBhAG0AcwAuAHQAeAB0AA0ACgAJACIAUwBlAGUAIAB3AGgAaQBjAGgAIABwAGEAcgBhAG0AZQB0AGUAcgBzACAAUABvAHcAZQByAFMAaABlAGwAbAAgAGcAbwB0ADoAIAAkAHAAYQByAGEAbQBzACIADQAKAAkADQAKAA

I want to do something like this, but I can't quite figure it out.

I "don't" want scripts that take a username/password from a file that's encrypted. It has to be from the above syntax/use and that will run from the Windows 2003 Task Schedule.
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Question by:klamerus
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18 Comments
 
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Expert Comment

by:Qlemo
ID: 40460720
First of all, PS2 script always run in PS3 and PS4, so that does not matter. There are some changes in behaviour, implying restrictions in 2.0, and for that the -version 2 parameter can be added to powershell.exe calls to keep that compatible if required (very rare).
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Expert Comment

by:Qlemo
ID: 40460722
Can you tell why you do not want to use an encrypted file for the credentials? PSCredentials are stored as Secure String, meaning only that user having created the string can use it.

The EncodedCommand feature is intended for ease of use with special characters. It is not encryption:
   -EncodedCommand   Accepts a base-64 encoded string version of a command, Use this to
                     submit commands to PowerShell that require complex quotation marks
                     or curly braces.

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Author Comment

by:klamerus
ID: 40460769
aha,

A ray of light on the encoded command.  I did not put 2 and 2 together.  My goal is that we can't have a clear text file that can be read.  It would accomplish that, but you're also saying that this can easily be reverse engineered (decoded) I think.

For us, it's not super sensitive credentials, so this would probably satisfy, but perhaps I should rethink this.

The reason I'd prefer this is that I can have a single script file that would accept 4 parameters:  username, password, directory from which to upload and FTP site to which to upload.  I could then use the same script with different command-line parameters solely through configuration of the Windows Task.  As a bonus I wouldn't have to have additional files laying around with encrypted info in them to keep track of.
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Author Comment

by:klamerus
ID: 40460772
Could you perhaps point to a good example of what you're describing?
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Expert Comment

by:David Johnson, CD, MVP
ID: 40460774
generate securepassword string
$secure = read-host "Enter Password" -assecurestring
$encrypted = convertfrom-securestring -secureString $secure  
$encrypted
 

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implement secure password
CmdletBinding()]
Param(
  [Parameter(Mandatory=$True,Position=1)]
   [string]$ftpserver,
	
   [Parameter(Mandatory=$True)]
   [string]$username,
   [Parameter(Mandatory=$True)]
   [string]$password 
)
$secure = convertto-securestring $password 
start-process ftp.exe -ArgumentList $ftpserver $username $secure

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Author Comment

by:klamerus
ID: 40460782
Can this commandlet be directly called via Windows Task Manager and if so what might that look like?
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Author Comment

by:klamerus
ID: 40460788
We of course know what the password we need to use is (which we keep stored in a system the entire company uses for storing credentials securely).

Is there any way that these can be reverse engineered from seeing them sitting in Task Manager?
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Expert Comment

by:Qlemo
ID: 40460798
With a file, and using PsCredentials, you would write this:
ConvertTo-SecureString "Password" -AsPlainText -Force |
  ConvertFrom-SecureString | Out-File C:\Passwordfile.txt

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for creating the file and
$cred = New-Object Management.Automation.PsCredential("Username",
  (Get-Content C:\Passwordfile.txt | ConvertTo-SecureString))

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for using it. The file is not necessary; you can use the output of ConvertFrom-SecureString (as David showed), and paste that into a variable definition or provide it as a string parameter, to use instead of (Get-Content C:\Passwordfile.txt.

I can't recall the code for using Web requests for uploading FTP, but I would not use FTP.EXE for that (as David did). FTP.EXE cannot use secure strings or PsCredentials, and is more difficult to automate.
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Expert Comment

by:Qlemo
ID: 40460802
A Secure String cannot be decoded by anyone else than the one having created it, on the same machine. While in memory, noone has direct access to the content. So, consider it safe.
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Author Comment

by:klamerus
ID: 40460843
Well, that sounds like a potential issue.  I have many team members and I need for them to set this up.  I can't have the encrypted string tied to a particular individual.  I need for the Task Manager to run the command to do the uploads.  Can a script running on the machine from the Task Manager decrypt the string?
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Expert Comment

by:Qlemo
ID: 40460882
In that case encoding (not encrypting) the password and optionally the user sounds best. Though - why not trigger a single task that processes a file containing all infos?
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Author Comment

by:klamerus
ID: 40460912
We're going to have a variety of these ftp uploads on various schedules for various systems.  Several teams will support these uploads as well (all on the same server).  So, having a separate Windows task to run each script is ideal.  It also makes it easy to modify schedules, add/remove, etc.

I'm back to the original question then though of I can't find a way or example of doing this.  I'm open for either an encrypted string for just the password for each task or encoding, but I don't have any examples of doing this that I can get to run.
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Expert Comment

by:Qlemo
ID: 40460924
No matter how you do it, there is no simple way. If  you really need to create individual tasks, a setup batch should be supplied to build the task or the command.
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Accepted Solution

by:
Qlemo earned 500 total points
ID: 40463531
The simple upload core script using a Base64-encoded password is (let's call it "C:\Scripts\upload-ftp.ps1"):
param(
  [String] $SourceDir,     <# Source path - folder, filemask:  C:\FTP\Site1          #>
  [String] $FTPLocation,   <# Target path - a FTP URI:         ftp://ftp.site1.com/  #>
  [String] $UserName,      <# Plain text username for FTP                            #>
  [char[]] $Password       <# Base64 encoded password string for FTP                 #>
)

$webclient = New-Object System.Net.WebClient 
$webclient.Credentials = New-Object System.Net.NetworkCredential($UserName, (-join [Char[]] [Convert]::FromBase64String($Password)))  
 
Get-ChildItem $SourceDir | % {
    $webclient.UploadFile((New-Object System.Uri($FTPLocation+$_.Name)), $_.FullName) 
} 

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An example call - with plain password - is
C:\Scripts\upload-ftp.ps1 c:\temp\ee\*.png ftp://ftp.site1.com/ TheBoss ([Convert]::ToBase64String([Char[]]'IncredibleSecretPassword'))

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Of course you would create your task with the base64 string instead. Is that something you could implement?
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Expert Comment

by:David Johnson, CD, MVP
ID: 40463597
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Expert Comment

by:Qlemo
ID: 40470511
I fail to see how PsFTP should help here. It is great for simplifying combined actions, but this question is about simple uploads. If anything, I would consider ftpuse at http://www.ferrobackup.com/ftpuse/,  allowing handling FTP as a network drive.
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Author Closing Comment

by:klamerus
ID: 40725982
One thing is that this is an encoded command-line and not encrypted.   Possible mistake on my part for not being explicit on use of the word encoded vs. encrypted.
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Expert Comment

by:Qlemo
ID: 40727275
Without implementing an own "encryption" method, you won't be able to fulfill your requirements. Basic encoding is depending on something, mostly on the user or hardware, to prevent from being used by others. Base64 encoding could be combined with something secret, but that would have to be a) reversible and b) visible in PS code or "hidden" in a DLL.
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