SET-ACL via powershell for computer object - powershell

Question

i am trying to modify a permission to multiple computers in my domain so that they are allowed to authenticate cross domain.
My code is simple however i keep getting an error.
Function Add-ADGroupACL
{
param([string]$Computername,[string]$Access)
#Get a reference to the RootDSE of the current domain
$rootdse = Get-ADRootDSE
#Get a reference to the current domain
$domain = Get-ADDomain
#Create a hashtable to store the GUID value of each extended right in the forest
$extendedrightsmap = #{}
Get-ADObject -SearchBase ($rootdse.ConfigurationNamingContext) -LDAPFilter `
"(&(objectclass=controlAccessRight)(rightsguid=*))" -Properties displayName,rightsGuid |
% {$extendedrightsmap[$_.displayName]=[System.GUID]$_.rightsGuid}
#Create a hashtable to store the GUID value of each schema class and attribute
$guidmap = #{}
Get-ADObject -SearchBase ($rootdse.SchemaNamingContext) -LDAPFilter `
"(schemaidguid=*)" -Properties lDAPDisplayName,schemaIDGUID |
% {$guidmap[$_.lDAPDisplayName]=[System.GUID]$_.schemaIDGUID}
#Get the computer object for modification on
$Computer = Get-ADComputer -Identity $Computername
#get the SID of the group you wish to add to the computer.
$GroupIdentity = New-Object System.Security.Principal.SecurityIdentifier(Get-ADGroup -Identity $Access).SID
$computersADPath = "AD:\" + $Computer.DistinguishedName
$ComputerACL = Get-ACL $computersADPath
#Create a new rule to add to the object
$newAccessRule = New-Object System.DirectoryServices.ActiveDirectoryAccessRule(
$GroupIdentity,"ExtendedRight",
"Allow",
$extendedrightsmap["Allowed To Authenticate"],
"None")
$newAccessRule
#Add the rule to the ACL
$ComputerACL.AddAccessRule($newAccessRule)
#Set Rules to the ACL
Set-Acl -AclObject $ComputerACL -Path $computersADPath
}
I have posted the entire function to make it easy.
Simply call this as so
Add-ADGroupACL -Computername 'TestComputer' -Access 'TestGroup'
end here is the error message that i keep getting
Set-Acl : This security ID may not be assigned as the owner of this object
At line:88 char:5
+ Set-Acl -AclObject $ComputerACL -Path $computersADPath
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (CN=testComputer,OU=Co...C=subdomain,DC=domain:String) [Set-Acl], ADException
+ FullyQualifiedErrorId : ADProvider:SetSecurityDescriptor:ADError,Microsoft.PowerShell.Commands.SetAclCommand
The Access Rule looks right. it shows this.
ActiveDirectoryRights : ExtendedRight
InheritanceType : None
ObjectType : 68b1d179-0d15-4d4f-ab71-46152e79a7bc
InheritedObjectType : 00000000-0000-0000-0000-000000000000
ObjectFlags : ObjectAceTypePresent
AccessControlType : Allow
IdentityReference : S-1-5-21-2926237862-3770063950-2320700579-361721
IsInherited : False
InheritanceFlags : None
PropagationFlags : None
Any help would be greatly appreciated.
Thank you.

Answer 1

For anyone else who gets this problem, the here is the solution.
Basically, how Get-ACL and Set-ACL works is that it retrieves the entire ACL. you make edits to the ACL and then Set-ACL attempts to rewrite the entire ACL.
More Info: https://learn.microsoft.com/en-us/windows/desktop/secauthz/access-control-entries
So basically you need to just create an ACE and add it to the ACL on the fly. this can best be done buy utilising DACLS
Code:
Function Add-ADGroupACEExtendedRight
{
param(
[string]$Computername = $(throw "Computer name must be specified"),
[string]$Access = $(throw "User or group in which to give acces must be specifieds"),
[string]$ExtendedRight = $(throw "Extended Right Property Name Required")
)
#Get the computer object for modification on
$Computer = Get-ADComputer -Identity $Computername
#get the SID of the group you wish to add to the computer.
$GroupIdentity = New-Object System.Security.Principal.SecurityIdentifier(Get-ADGroup -Identity $Access).SID
#Set Permissions
dsacls $Computer.DistinguishedName /G $GroupIdentity":CA;"$ExtendedRight
}
Usage:
Add-ADGroupACEExtendedRight -Computername "TestAsset" -Access "GroupID" -ExtendedRight "Allowed To Authenticate"
you can add any extended right here.
more information on DACLS: https://technet.microsoft.com/pt-pt/library/cc787520%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396