[Forum FAQ] Using PowerShell to assign permissions on Active Directory objects

Question

As we all know, the
ActiveDirectoryAccessRule class is used to represent an access control entry (ACE) in the discretionary access control list (DACL) of an Active Directory Domain Services object.
To set the permissions on Active Directory objects, the relevant classes and their enumerations are listed as below:
System.DirectoryServices.ActiveDirectoryAccessRule class:
http://msdn.microsoft.com/en-us/library/system.directoryservices.activedirectoryaccessrule(v=vs.110).aspx
System.DirectoryServices.ActiveDirectoryRights
class:
http://msdn.microsoft.com/en-us/library/system.directoryservices.activedirectoryrights(v=vs.110).aspx
System.Security.AccessControl.AccessControlType class:
http://msdn.microsoft.com/en-us/library/w4ds5h86(v=vs.110).aspx
System.DirectoryServices.ActiveDirectorySecurityInheritance class:
http://msdn.microsoft.com/en-us/library/system.directoryservices.activedirectorysecurityinheritance(v=vs.110).aspx
In this article, we introduce three ways to get and set the ACE on an Active Directory object. In general,
we use Active Directory Service Interfaces (ADSI) or
Active Directory module cmdlets
with the Get-Acl and Set-Acl cmdlets to assign simple permissions on Active Directory objects. In addition, we can use the extended rights and GUID settings to execute
more complex permission settings.
Method 1: Using ADSI
  1. Get current permissions of an organization unit (OU)
We can use the PowerShell script below to get current permissions of an organization unit and you just need to define the name of the OU.
$Name = "OU=xxx,DC=com"
$ADObject = [ADSI]"LDAP://$Name"
$aclObject = $ADObject.psbase.ObjectSecurity
$aclList = $aclObject.GetAccessRules($true,$true,[System.Security.Principal.SecurityIdentifier])
$output=@()
foreach($acl in $aclList)
$objSID = New-Object System.Security.Principal.SecurityIdentifier($acl.IdentityReference)
     $info = @{
'ActiveDirectoryRights' = $acl.ActiveDirectoryRights;
'InheritanceType' = $acl.InheritanceType;
'ObjectType' = $acl.ObjectType;
'InheritedObjectType' = $acl.InheritedObjectType;
'ObjectFlags' = $acl.ObjectFlags;
'AccessControlType' = $acl.AccessControlType;
'IdentityReference' = $acl.IdentityReference;
'NTAccount' = $objSID.Translate( [System.Security.Principal.NTAccount] );
'IsInherited' = $acl.IsInherited;
'InheritanceFlags' = $acl.InheritanceFlags;
'PropagationFlags' = $acl.PropagationFlags;
$obj = New-Object -TypeName PSObject -Property $info
$output+=$obj}
$output
In the figure below, you can see the results of running the script above:
Figure 1．
2. Assign a computer object with Full Control permission on an OU
We can use the script below to delegate Full Control permission to the computer objects within an OU:
$SysManObj = [ADSI]("LDAP://OU=test….,DC=com") #get the OU object
$computer = get-adcomputer "COMPUTERNAME" #get the computer object which will be assigned with Full Control permission within an OU
$sid = [System.Security.Principal.SecurityIdentifier] $computer.SID
$identity = [System.Security.Principal.IdentityReference] $SID
$adRights = [System.DirectoryServices.ActiveDirectoryRights] "GenericAll"
$type = [System.Security.AccessControl.AccessControlType] "Allow"
$inheritanceType = [System.DirectoryServices.ActiveDirectorySecurityInheritance] "All"
$ACE = New-Object System.DirectoryServices.ActiveDirectoryAccessRule $identity,$adRights,$type,$inheritanceType #set permission
$SysManObj.psbase.ObjectSecurity.AddAccessRule($ACE)
$SysManObj.psbase.commitchanges()
After running the script above, you can check the computer object in Active Directory Users and Computers (ADUC) and it is under the Security tab in OU Properties.
Method 2: Using Active Directory module with the Get-Acl and Set-Acl cmdlets
You can use the script below to get and assign Full Control permission to a computer object on an OU:
$acl = get-acl "ad:OU=xxx,DC=com"
$acl.access #to get access right of the OU
$computer = get-adcomputer "COMPUTERNAME"
$sid = [System.Security.Principal.SecurityIdentifier] $computer.SID
# Create a new access control entry to allow access to the OU
$identity = [System.Security.Principal.IdentityReference] $SID
$adRights = [System.DirectoryServices.ActiveDirectoryRights] "GenericAll"
$type = [System.Security.AccessControl.AccessControlType] "Allow"
$inheritanceType = [System.DirectoryServices.ActiveDirectorySecurityInheritance] "All"
$ACE = New-Object System.DirectoryServices.ActiveDirectoryAccessRule $identity,$adRights,$type,$inheritanceType
# Add the ACE to the ACL, then set the ACL to save the changes
$acl.AddAccessRule($ace)
Set-acl -aclobject $acl "ad:OU=xxx,DC=com"
Method 3: Using GUID setting
The scripts above can only help us to complete simple tasks, however, we may want to execute more complex permission settings. In this scenario, we can use GUID settings to achieve
that.
The specific ACEs allow an administrator to delegate Active Directory specific rights (i.e. extended rights) or read/write access to a property set (i.e. a named collection of attributes) by
setting ObjectType field in an object specific ACE to the
rightsGuid of the extended right or property set. The delegation can also be created to target child objects of a specific class by setting the
InheritedObjectType field to the schemaIDGuid of the class.
We choose to use this pattern: ActiveDirectoryAccessRule(IdentityReference, ActiveDirectoryRights, AccessControlType, Guid, ActiveDirectorySecurityInheritance, Guid)
You can use the script below to
assign the group object with the permission to change user password on all user objects within an OU.
$acl = get-acl "ad:OU=xxx,DC=com"
$group = Get-ADgroup xxx
$sid = new-object System.Security.Principal.SecurityIdentifier $group.SID
# The following object specific ACE is to grant Group permission to change user password on all user objects under OU
$objectguid = new-object Guid 
00299570-246d-11d0-a768-00aa006e0529 # is the rightsGuid for the extended right User-Force-Change-Password (“Reset Password”) 
class
$inheritedobjectguid = new-object Guid 
bf967aba-0de6-11d0-a285-00aa003049e2 # is the schemaIDGuid for the user
$identity = [System.Security.Principal.IdentityReference] $SID
$adRights = [System.DirectoryServices.ActiveDirectoryRights] "ExtendedRight"
$type = [System.Security.AccessControl.AccessControlType]
"Allow"
$inheritanceType = [System.DirectoryServices.ActiveDirectorySecurityInheritance] "Descendents"
$ace = new-object System.DirectoryServices.ActiveDirectoryAccessRule $identity,$adRights,$type,$objectGuid,$inheritanceType,$inheritedobjectguid
$acl.AddAccessRule($ace)
Set-acl -aclobject $acl "ad:OU=xxx,DC=com"
The figure below shows the result of running the script above:
Figure 2．
In addition, if you want to assign other permissions, you can change the GUID values in the script above. The common GUID values are listed as below:
$guidChangePassword     
= new-object Guid ab721a53-1e2f-11d0-9819-00aa0040529b
$guidLockoutTime        
= new-object Guid 28630ebf-41d5-11d1-a9c1-0000f80367c1
$guidPwdLastSet         
= new-object Guid bf967a0a-0de6-11d0-a285-00aa003049e2
$guidComputerObject     
= new-object Guid bf967a86-0de6-11d0-a285-00aa003049e2
$guidUserObject         
= new-object Guid bf967aba-0de6-11d0-a285-00aa003049e2
$guidLinkGroupPolicy    
= new-object Guid f30e3bbe-9ff0-11d1-b603-0000f80367c1
$guidGroupPolicyOptions 
= new-object Guid f30e3bbf-9ff0-11d1-b603-0000f80367c1
$guidResetPassword      
= new-object Guid 00299570-246d-11d0-a768-00aa006e0529
$guidGroupObject        
= new-object Guid BF967A9C-0DE6-11D0-A285-00AA003049E2                                          
$guidContactObject      
= new-object Guid 5CB41ED0-0E4C-11D0-A286-00AA003049E2
$guidOUObject           
= new-object Guid BF967AA5-0DE6-11D0-A285-00AA003049E2
$guidPrinterObject      
= new-object Guid BF967AA8-0DE6-11D0-A285-00AA003049E2
$guidWriteMembers   
    = new-object Guid bf9679c0-0de6-11d0-a285-00aa003049e2
$guidNull               
= new-object Guid 00000000-0000-0000-0000-000000000000
$guidPublicInformation  
= new-object Guid e48d0154-bcf8-11d1-8702-00c04fb96050
$guidGeneralInformation 
= new-object Guid 59ba2f42-79a2-11d0-9020-00c04fc2d3cf
$guidPersonalInformation = new-object Guid 77B5B886-944A-11d1-AEBD-0000F80367C1
$guidGroupMembership    
= new-object Guid bc0ac240-79a9-11d0-9020-00c04fc2d4cf
More information:
Add Object Specific ACEs using Active Directory Powershell
http://blogs.msdn.com/b/adpowershell/archive/2009/10/13/add-object-specific-aces-using-active-directory-powershell.aspx
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Answer 1

The ActiveDirectoryAccessRule has more than one constructor, but yes, you've interpreted the one that takes six arguments correctly.
Those GUIDs are different (check just before the first dash). Creating that ACE will create an empty GUID for InheritedObjectType, though, because you're telling it to apply to the Object only ([System.DirectoryServices.ActiveDirectorySecurityInheritance]::None).
Since the ACE will only apply to the object, there's no need to worry about what types of objects will inherit it.
If you've got time, check out
this module. It will let you view the security descriptors in a much friendlier format. Try both version 3.0 and the version 4.0 preview:
Sample version 3.0:
# This is going to be kind of slow, and it will take a few seconds the first time
# you run it because it has to build the list of GUID <--> Property/Class/etc objects
Get-ADGroup GroupY |
Get-AccessControlEntry -ObjectAceType member -InheritedObjectAceType group -ActiveDirectoryRights WriteProperty
# Same as the previous command, except limit it to access granted to GroupX
Get-ADGroup GroupY |
Get-AccessControlEntry -ObjectAceType member -InheritedObjectAceType group -ActiveDirectoryRights WriteProperty -Principal GroupX
Here's version 4.0. It's way faster than 3.0, but it's missing the -ObjectAceType and -InheritedObjectAceType parameters on Get-AccessControlEntry (don't worry, when they come back they'll be better than in 3.0):
Get-ADGroup GroupY |
Get-AccessControlEntry
Get-ADGroup GroupY |
Get-AccessControlEntry -ActiveDirectoryRights WriteProperty
Get-ADGroup GroupY |
Get-AccessControlEntry -ActiveDirectoryRights WriteProperty -Principal GroupX
# You can do a Where-Object filter until the parameters are added back to Get-AccessControlEntry:
Get-ADGroup GroupY |
Get-AccessControlEntry -ActiveDirectoryRights WriteProperty |
where { $_.AccessMask -match "All Prop|member Prop" }
Get-ADGroup GroupY |
Get-AccessControlEntry -ActiveDirectoryRights WriteProperty |
where { $_.ObjectAceType -in ($null, [guid]::Empty, "bf9679c0-0de6-11d0-a285-00aa003049e2") }
Get-ADGroup GroupY |
Get-AccessControlEntry -ActiveDirectoryRights WriteProperty |
where { $_.AccessMask -match "All Prop|member Prop" -and $_.AppliesTo -match "group"}
That's just for viewing. Version 3.0 can add and remove access, or you can use New-AccessControlEntry to replace your call to New-Object, and you can still use Get-Acl and Set-Acl. The benefit to New-AccessControlEntry is that you can do something like this:
New-AccessControlEntry -Principal GroupX -ActiveDirectoryRights WriteProperty -ObjectAceType member -InheritedObjectAceType group #-AppliesTo Object