Skip to main content

EWS Powershell default Mailbox Folder ACE audit script

The default Access Control Entry ACE in an Exchange Mailbox Folder DACL controls the rights that all authenticated users have to a particularity mailbox folder. Generally from a security perspective its something you don't want users to use as they may not understand when then set this ACE they are giving all people access to certain information. Eg Giving the default user reviewer rights to your Inbox means everyone in the Exchange org can now read mailbox in you Inbox which may not provide much privacy to your email. The following script will enumerate the permissions on every folder in a Mailbox and then produce a report of the folders where the default ACE isn't set to none. For most users the only folder that should show up in the report in the calendar folder. This script uses EWS but you could also use the Exchange Management Shell Get-MailboxFolderPermission cmdlet.

To run this script you need to feed is with a CSV file that contains the SMTPAddress of the Mailboxes you want it to run against. I've put a download of this script here the script itself looks like

  1. ## Get the Mailbox to Access from the 1st commandline argument  
  2. $Script:rptCollection = @()  
  3. ## Load Managed API dll    
  4. Add-Type -Path "C:\Program Files\Microsoft\Exchange\Web Services\2.0\Microsoft.Exchange.WebServices.dll"    
  5.     
  6. ## Set Exchange Version    
  7. $ExchangeVersion = [Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2010_SP2    
  8.     
  9. ## Create Exchange Service Object    
  10. $service = New-Object Microsoft.Exchange.WebServices.Data.ExchangeService($ExchangeVersion)    
  11.     
  12. ## Set Credentials to use two options are availible Option1 to use explict credentials or Option 2 use the Default (logged On) credentials    
  13.     
  14. #Credentials Option 1 using UPN for the windows Account    
  15. $psCred = Get-Credential    
  16. $creds = New-Object System.Net.NetworkCredential($psCred.UserName.ToString(),$psCred.GetNetworkCredential().password.ToString())    
  17. $service.Credentials = $creds        
  18.     
  19. #Credentials Option 2    
  20. #service.UseDefaultCredentials = $true    
  21.     
  22. ## Choose to ignore any SSL Warning issues caused by Self Signed Certificates    
  23.     
  24. ## Code From http://poshcode.org/624  
  25. ## Create a compilation environment  
  26. $Provider=New-Object Microsoft.CSharp.CSharpCodeProvider  
  27. $Compiler=$Provider.CreateCompiler()  
  28. $Params=New-Object System.CodeDom.Compiler.CompilerParameters  
  29. $Params.GenerateExecutable=$False  
  30. $Params.GenerateInMemory=$True  
  31. $Params.IncludeDebugInformation=$False  
  32. $Params.ReferencedAssemblies.Add("System.DLL") | Out-Null  
  33.   
  34. $TASource=@' 
  35.   namespace Local.ToolkitExtensions.Net.CertificatePolicy{ 
  36.     public class TrustAll : System.Net.ICertificatePolicy { 
  37.       public TrustAll() {  
  38.       } 
  39.       public bool CheckValidationResult(System.Net.ServicePoint sp, 
  40.         System.Security.Cryptography.X509Certificates.X509Certificate cert,  
  41.         System.Net.WebRequest req, int problem) { 
  42.         return true; 
  43.       } 
  44.     } 
  45.   } 
  46. '@   
  47. $TAResults=$Provider.CompileAssemblyFromSource($Params,$TASource)  
  48. $TAAssembly=$TAResults.CompiledAssembly  
  49.   
  50. ## We now create an instance of the TrustAll and attach it to the ServicePointManager  
  51. $TrustAll=$TAAssembly.CreateInstance("Local.ToolkitExtensions.Net.CertificatePolicy.TrustAll")  
  52. [System.Net.ServicePointManager]::CertificatePolicy=$TrustAll  
  53.   
  54. ## end code from http://poshcode.org/624  
  55.     
  56. ## Set the URL of the CAS (Client Access Server) to use two options are availbe to use Autodiscover to find the CAS URL or Hardcode the CAS to use    
  57.     
  58. #CAS URL Option 1 Autodiscover    
  59.   
  60.      
  61. #CAS URL Option 2 Hardcoded    
  62.     
  63. #$uri=[system.URI] "https://casservername/ews/exchange.asmx"    
  64. #$service.Url = $uri      
  65.     
  66. ## Optional section for Exchange Impersonation    
  67.     
  68. #$service.ImpersonatedUserId = new-object Microsoft.Exchange.WebServices.Data.ImpersonatedUserId([Microsoft.Exchange.WebServices.Data.ConnectingIdType]::SmtpAddress, $MailboxName)   
  69.   
  70. # Bind to the Inbox Folder  
  71. #Define Function to convert String to FolderPath    
  72. function ConvertToString($ipInputString){    
  73.     $Val1Text = ""    
  74.     for ($clInt=0;$clInt -lt $ipInputString.length;$clInt++){    
  75.             $Val1Text = $Val1Text + [Convert]::ToString([Convert]::ToChar([Convert]::ToInt32($ipInputString.Substring($clInt,2),16)))    
  76.             $clInt++    
  77.     }    
  78.     return $Val1Text    
  79. }   
  80.   
  81. function Process-Mailbox{  
  82.     param (  
  83.             $SmtpAddress = "$( throw 'SMTPAddress is a mandatory Parameter' )"  
  84.           )  
  85.     process{  
  86.   
  87.         #Define Extended properties    
  88.         $PR_FOLDER_TYPE = new-object Microsoft.Exchange.WebServices.Data.ExtendedPropertyDefinition(13825,[Microsoft.Exchange.WebServices.Data.MapiPropertyType]::Integer);    
  89.         $folderidcnt = new-object Microsoft.Exchange.WebServices.Data.FolderId([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::MsgFolderRoot,$SmtpAddress)  
  90.         #Define the FolderView used for Export should not be any larger then 1000 folders due to throttling    
  91.         $fvFolderView =  New-Object Microsoft.Exchange.WebServices.Data.FolderView(1000)    
  92.         #Deep Transval will ensure all folders in the search path are returned    
  93.         $fvFolderView.Traversal = [Microsoft.Exchange.WebServices.Data.FolderTraversal]::Deep;    
  94.         $psPropertySet = new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.BasePropertySet]::FirstClassProperties)    
  95.         $PR_Folder_Path = new-object Microsoft.Exchange.WebServices.Data.ExtendedPropertyDefinition(26293, [Microsoft.Exchange.WebServices.Data.MapiPropertyType]::String);    
  96.         #Add Properties to the  Property Set    
  97.         $psPropertySet.Add($PR_Folder_Path);    
  98.         $fvFolderView.PropertySet = $psPropertySet;    
  99.         #The Search filter will exclude any Search Folders    
  100.         $sfSearchFilter = new-object Microsoft.Exchange.WebServices.Data.SearchFilter+IsEqualTo($PR_FOLDER_TYPE,"1")    
  101.         $fiResult = $null  
  102.         #Process the Mailbox Root Folder  
  103.         $psPropset = new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.BasePropertySet]::FirstClassProperties)    
  104.         $psPropset.Add([Microsoft.Exchange.WebServices.Data.FolderSchema]::Permissions);  
  105.         #The Do loop will handle any paging that is required if there are more the 1000 folders in a mailbox    
  106.         do {    
  107.             $fiResult = $Service.FindFolders($folderidcnt,$sfSearchFilter,$fvFolderView)    
  108.             foreach($ffFolder in $fiResult.Folders){    
  109.                 $foldpathval = $null    
  110.                 #Try to get the FolderPath Value and then covert it to a usable String     
  111.                 if ($ffFolder.TryGetProperty($PR_Folder_Path,[ref] $foldpathval))    
  112.                 {    
  113.                     $binarry = [Text.Encoding]::UTF8.GetBytes($foldpathval)    
  114.                     $hexArr = $binarry | ForEach-Object { $_.ToString("X2") }    
  115.                     $hexString = $hexArr -join ''    
  116.                     $hexString = $hexString.Replace("FEFF", "5C00")    
  117.                     $fpath = ConvertToString($hexString)    
  118.                 }    
  119.                 "Processing FolderPath : " + $fpath    
  120.                 $ffFolder.Load($psPropset)  
  121.                 foreach($Permission in  $ffFolder.Permissions){  
  122.                     if($Permission.UserId.StandardUser -eq [Microsoft.Exchange.WebServices.Data.StandardUser]::Default){  
  123.                         if($Permission.DisplayPermissionLevel -ne "None"){  
  124.                             $rptObj = "" | Select Mailbox,FolderPath,FolderType,PermissionLevel  
  125.                             $rptObj.Mailbox = $SmtpAddress  
  126.                             $rptObj.FolderPath = $fpath  
  127.                             $rptObj.FolderType = $ffFolder.FolderClass  
  128.                             $rptObj.PermissionLevel = $Permission.DisplayPermissionLevel  
  129.                             $Script:rptCollection += $rptObj  
  130.                         }   
  131.                     }  
  132.                 }  
  133.   
  134.             }   
  135.             $fvFolderView.Offset += $fiResult.Folders.Count  
  136.         }while($fiResult.MoreAvailable -eq $true)   
  137.     }  
  138. }  
  139. Import-Csv -Path $args[0] | ForEach-Object{  
  140.     if($service.url -eq $null){  
  141.         $service.AutodiscoverUrl($_.SmtpAddress,{$true})   
  142.         "Using CAS Server : " + $Service.url   
  143.     }    
  144.     Process-Mailbox -SmtpAddress $_.SmtpAddress  
  145. }  
  146. $Script:rptCollection  
Labels:

Popular posts from this blog

Exporting and Uploading Mailbox Items using Exchange Web Services using the new ExportItems and UploadItems operations in Exchange 2010 SP1

Two new EWS Operations ExportItems and UploadItems where introduced in Exchange 2010 SP1 that allowed you to do a number of useful things that where previously not possible using Exchange Web Services. Any object that Exchange stores is basically a collection of properties for example a message object is a collection of Message properties, Recipient properties and Attachment properties with a few meta properties that describe the underlying storage thrown in. Normally when using EWS you can access these properties in a number of a ways eg one example is using the strongly type objects such as emailmessage that presents the underlying properties in an intuitive way that's easy to use. Another way is using Extended Properties to access the underlying properties directly. However previously in EWS there was no method to access every property of a message hence there is no way to export or import an item and maintain full fidelity of every property on that item (you could export the...
Read more

Sending a Message in Exchange Online via REST from an Arduino MKR1000

This is part 2 of my MKR1000 article, in this previous post  I looked at sending a Message via EWS using Basic Authentication.  In this Post I'll look at using the new Outlook REST API  which requires using OAuth authentication to get an Access Token. The prerequisites for this sketch are the same as in the other post with the addition of the ArduinoJson library  https://github.com/bblanchon/ArduinoJson  which is used to parse the Authentication Results to extract the Access Token. Also the SSL certificates for the login.windows.net  and outlook.office365.com need to be uploaded to the devices using the wifi101 Firmware updater. To use Token Authentication you need to register an Application in Azure https://msdn.microsoft.com/en-us/office/office365/howto/add-common-consent-manually  with the Mail.Send permission. The application should be a Native Client app that use the Out of Band Callback urn:ietf:wg:oauth:2.0:oob. You ...
Read more

The MailboxConcurrency limit and using Batching in the Microsoft Graph API

If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background   The Mailbox  concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons.  Batching in the Gr...
Read more
All sample scripts and source code is provided by for illustrative purposes only. All examples are untested in different environments and therefore, I cannot guarantee or imply reliability, serviceability, or function of these programs.

All code contained herein is provided to you "AS IS" without any warranties of any kind. The implied warranties of non-infringement, merchantability and fitness for a particular purpose are expressly disclaimed.