Given a user's SID, how can I get the AD DirectoryEntry?

Question

I have the user's SID as byte[] within windowsPrincipal.getIdentity().getSid(). How can I get an Active Directory entry (DirectoryEntry) from the SID?

Overcharge

Answer 1

Use the SecurityIdentifier class to convert the sid from byte[] format to string and then bind directly to the object:

DirectoryEntry OpenEntry(byte[] sidAsBytes)
{
    var sid = new SecurityIdentifier(sidAsBytes, 0);

    return new DirectoryEntry(string.Format("LDAP://<SID={0}>", sid.ToString()));
}

Reek

Answer 2

I found this example in c#

    // SID must be in Security Descriptor Description Language (SDDL) format
    // The PrincipalSearcher can help you here too (result.Sid.ToString())
    public void FindByIdentitySid()
    {
        UserPrincipal user = UserPrincipal.FindByIdentity(
            adPrincipalContext,
            IdentityType.Sid,
            "S-1-5-21-2422933499-3002364838-2613214872-12917");
        Console.WriteLine(user.DistinguishedName);
    }

Converted to VB.NET:

    ' SID must be in Security Descriptor Description Language (SDDL) format
    ' The PrincipalSearcher can help you here too (result.Sid.ToString())
    Public Sub FindByIdentitySid()
        Dim user As UserPrincipal = UserPrincipal.FindByIdentity(adPrincipalContext,     IdentityType.Sid, "S-1-5-21-2422933499-3002364838-2613214872-12917")
        Console.WriteLine(user.DistinguishedName)
    End Sub

Obviously you can then:

    dim de as new DirectoryEntry("LDAP://" & user.DistinguishedName)

To get the SID = S-1-5-21-* (sorry VB.NET)

    ' Convert ObjectSID to a String

    ' http://social.msdn.microsoft.com/forums/en-US/netfxbcl/thread/57452aab-4b68-4444-aefa-136b387dd06e

    Dim ADpropSid As Byte()
    ADpropSid = de.Properties("objectSid").Item(0)    
    ' in my test the byte field looks like this : 01 02 00 00 00 00.......37 02 00 00
    Dim SID As New System.Security.Principal.SecurityIdentifier(ADpropSid, 0)

I haven't tested the C# or used the converted version yet myself, but have used the above to return the SID in SDDL format.

Rohrer

wow you and i have different definitions of "obvious". Why can you do a query on "LDAP://" & user.DistinguishedName like that? Don't you need to specify hostname etc? Does that require you are on the same machine that has active directory access? – Fayum

Answer 3

The easiest way I've found is using LDAP binding. Similar to what Nick Giles said. More info at MSDN

''' <summary>
''' Gets the DirectoryEntry identified by this SecurityIdentifier.
''' </summary>
''' <param name="id">The SecurityIdentifier (SID).</param>
<System.Runtime.CompilerServices.Extension()> _
Public Function GetDirectoryEntry(ByVal id As SecurityIdentifier) As DirectoryEntry
    Const sidBindingFormat As String = "LDAP://AOT/<SID={0}>"

    Return New DirectoryEntry(String.Format(sidBindingFormat, id.Value))
End Function

Bedridden

Answer 4

This can also be done in PowerShell, as long as you have .Net 3.5 or 4.0 available (see https://gist.github.com/882528 if you don't by default)

add-type -assemblyname system.directoryservices.accountmanagement
$adPrincipalContext = 
    New-Object System.DirectoryServices.AccountManagement.PrincipalContext( 
    [System.DirectoryServices.AccountManagement.ContextType]::Domain)
$user = [system.directoryservices.accountmanagement.userprincipal]::findbyidentity(
    $adPrincipalContext
    , [System.DirectoryServices.AccountManagement.IdentityType]::Sid
    , "S-1-5-21-2422933499-3002364838-2613214872-12917")
$user.DisplayName
$user.DistinguishedName

Schematic