Access Denied errors accessing IIS WMI provider from ASP

Question

I have a Windows 2003 server running IIS 6 and have some scripts that do automated setup and creation of websites. They are not working on a new server I cam commissioning (they already work happily on 3 other W2K3 servers). The problem appear to boil down to WMI security on the IIS provider. The ASP code below represents the problem (although it is not the original code that causes the problem - this is a simplified demonstration of the problem).

Set wmiProvider = GetObject("winmgmts:\\.\root\MicrosoftIISv2")
If wmiProvider is Nothing Then
Response.Write "Failed to get WMI provider MicrosoftIISv2<br>"
End If

Response.Write "Querying for IISWebService...<br>"
Set colItems = wmiProvider.ExecQuery("Select * From IISWebServer",,0)
Response.Write "Error: " & Hex(Err.Number) & " (" & Err.Description & ")<br>"

If I run this in my browser, I get an access denied error reported after the ExecQuery call. I have set WMI access for the IUSR_ user from the Root branch all the way down. In fact, I can query for IP address information using the CIMV2 provider quite happily. If I put the IUSR user in the machine admins group it all works, but I don't really want to do that.

This must be a DCOM/WMI security problem, but I can't work out what else there is. Can anyone shed any light?

Answer 1

After reading G. Stoynev's comment asking if any events were logged in the Windows Logs, I checked the event logs on the server to which I'm attempting to access IIS remotely via WMI, and lo and behold I found an event with the following text:

Access to the root\WebAdministration namespace was denied because the namespace is marked with RequiresEncryption but the script or application attempted to connect to this namespace with an authentication level below Pkt_Privacy. Change the authentication level to Pkt_Privacy and run the script or application again.

See the code in this answer to the related SO question c# - "Access is denied" Exception with WMI.

Here's some example C# code that I added that seemed to resolve this issue for me:

ConnectionOptions options = new ConnectionOptions();
options.Authentication = AuthenticationLevel.PacketPrivacy;
ManagementScope managementScope = new ManagementScope(@"\\remote-server\root\WebAdministration", options);
// ...