How to test writing to a file share path using credential? - powershell

Question

I have an array of Credential objects and I would like to test that these credentials have permissions to write a file to a file share.
I was going to do something like
$myPath = "\\path\to\my\share\test.txt"
foreach ($cred in $credentialList)
{
"Testing" | Out-File -FilePath $myPath -Credential $cred
}
but then I discovered that Out-File doesn't take Credential as a parameter. What's the best way to solve this?

Answer 1

You can use New-PSDrive:
$myPath = "\\path\to\my\share"
foreach ($cred in $credentialList)
{
New-PSDrive Test -PSProvider FileSystem -Root $myPath -Credential $Cred
"Testing" | Out-File -FilePath Test:\test.txt
Remove-PSDrive Test
}

Answer 2

Here is asituation where an old exe (net.exe) seems to do better than powershell...
I guess you could try to map a network drive with the credential provided then test to write a file to that drive :
$cred=get-credential
$pass=$cred.GetNetworkCredential().Password
net use q: \\servername\share $pass /user:$cred.username

Answer 3

Use this script taken from Microsofts TechNet Script Center : http://gallery.technet.microsoft.com/scriptcenter/Lists-all-the-shared-5ebb395a
It is a lot easier to alter to fit your needs then to start completely from scratch.
Open up ListSharedFolderPermissions.ps1, and find the three $Properties vars. add a line at the top of each one so you can tell which user your looking at, so it should now look like this:
$Properties = #{'Username' = $Credential.UserName
'ComputerName' = $ComputerName
. . . . . }
Next, add your new Username property to the select-object line (3 times) :
$Objs|Select-Object Username,ComputerName,ConnectionStatus,SharedFolderName,SecurityPrincipal, `
FileSystemRights,AccessControlType
Once youve added those small pieces in the six appropriate places your script is ready to use:
cd c:\Path\where\you\put\ps1\file
$permissions = #()
$myPath = "computername"
foreach ($cred in $credentialList)
{
$permissions += .\ListAllSharedFolderPermission.ps1 -ComputerName $myPath -Credential $cred
$permissions += " "
}
$permissions | Export-Csv -Path "C:\Permission.csv" -NoTypeInformation

Answer 4

Try using the Invoke-Command function. It will take a credential object and allow you to run an arbitrary script block under that command. You can use that to test out writing the file
Invoke-Command -ScriptBlock { "Testing" | Out-File $myPath } -Credential $cred

Answer 5

I think the Invoke-command approach should work. But if nothing works you can try the powershell impersonation module. It successfully impersonates a user for most Powershell commands without the -Credential switch.

Answer 6

A few ideas:
Create your own PowerShell Provider
Impersonate a user and then write to the share (not sure if possible in powershell)
Use net use d:... as #Kayasax has suggested
Use WScript.Network
I'm very interested in the PowerShell provider myself, but I decided to make something real quick so I went with using the WScript.Network library. I used a hash table to track whether a user would be "authenticated" or not.
$credentials = #() # List of System.Net.NetworkCredential objects
$authLog = #{}
$mappedDrive = 'z:'
$tmpFile = $mappedDrive, '\', [guid]::NewGuid(), '.tmp' -join ''
$path = [io.path]::GetPathRoot('\\server\share\path')
$net = new-object -comObject WScript.Network
foreach ($c in $credentials) {
if ($authLog.ContainsKey($c.UserName)) {
# Skipping because we've already tested this user.
continue
}
try {
if (Test-Path $mappedDrive) {
$net.RemoveNetworkDrive($mappedDrive, 1) # 1 to force
}
# Attempt to map drive and write to it
$net.MapNetworkDrive($mappedDrive, $path, $false, $c.UserName, $c.Password)
out-file $tmpFile -inputObject 'test' -force
# Cleanup
Remove-Item $tmpFile -force
$net.RemoveNetworkDrive($mappedDrive, 1)
# Authenticated.
# We shouldn't have reached this if we failed to mount or write
$authLog.Add($c.UserName, 'Authorized')
}
catch [Exception] {
# Unathenticated
$authLog.Add($c.UserName, 'Unauthorized')
}
}
$authLog
# Output
Name Value
---- -----
desktop01\user01 Authorized
desktop01\user02 Unauthorized