VB.net WMI Win32_NtlogEvent problem, please help

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G

Guest

First I wrote some _VBScript to get info from OS, and now I wrote some code
in VB.Net, and I have a problem now.



Look at this script in vbs

List1.vbs:

strComputer = "."

Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")

strWQL="SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE
TargetInstance ISA ""Win32_NTLogEvent"" "

Set objEventSource = objWMIService.ExecNotificationQuery(strWQL)

Do

Set objLatestEvent = colMonitoredEvents.NextEvent

Wscript.Echo "OK"

Loop



I use it to register the Win32_ntlogEvent , so that i can get some info
where a new log written into the logfiles. List1 works very well on Windows
2003 Server, but when I try it on Windows 2000 Server, it echoed the
connection was refused .



So I edited it into List2,



strComputer = "."

Set objWMIService = GetObject("winmgmts:" & "{impersonationLevel=
impersonate, (Security)}!\\" & strComputer & "\root\cimv2")

Set colMonitoredEvents = objWMIService.ExecNotificationQuery _

("Select * from __instancecreationevent WITHIN 5 where TargetInstance
isa 'Win32_NTLogEvent' ")

Do

Set objLatestEvent = colMonitoredEvents.NextEvent

Wscript.Echo "OK"

Loop



and list2 works well on Window2000. i noticed the security setting so when I
wrote the code(List3) in vb.net, I added

" watcher.Scope.Options.Impersonation = ImpersonationLevel.Impersonate

watcher.Scope.Options.Authentication = AuthenticationLevel.Default

" options in the vb.net code, but the bin still can not run on windows2000,
while it works well on Server2003.



i am puzzled! : ( ,



List3:


Imports System.management

Module Module1

Sub main()

Dim eventQuery As New EventQuery("SELECT * FROM
__InstanceCreationEvent WHERE TargetInstance ISA 'Win32_NTLogEvent' ")



'Initialize an event watcher object with this query

Dim watcher As New ManagementEventWatcher

watcher.Scope.Path.Server = "."

watcher.Scope.Path.Path = "\\.\root\CIMV2"

watcher.Scope.Path.NamespacePath = "root\CIMV2"

watcher.Scope.Options.Impersonation = ImpersonationLevel.Impersonate

watcher.Scope.Options.Authentication = AuthenticationLevel.Default

watcher.Scope.Options.EnablePrivileges = False

watcher.Query = eventQuery



watcher.Start()

MsgBox("Listening startedï¼")



Dim handler As New EventHandler

AddHandler watcher.EventArrived, AddressOf handler.HandleEvent



System.Threading.Thread.Sleep(-1)



End Sub

End Module



Public Class EventHandler

Public Sub HandleEvent(ByVal sender As Object, ByVal e As
EventArrivedEventArgs)

Console.Write("OK")

End Sub

End Class



but after I changed the Query String to :

'Dim eventQuery As New EventQuery("SELECT * FROM __InstanceCreationEvent
WHERE TargetInstance ISA 'Win32_NTLogEvent' and TargetInstance ='Application'
")



The bin could run well under windows2000 too, but if you change the
targetinstance to Security, you get the access denied message again.



So finally i have two questions:



Why can not i register to the Win32_NtlogEvent, bu t i can register to the
application part in Win32_ntlogevent?

Is that a security problem?



Thank you for you time.
 
Hello Jason,

I am not an expert on this but I have written some vb.net code to do
something similar. My understanding is the even if you run this with an
administravtive level account some security permissions are not enabled
unless you explicitly do so.

The line "watcher.Scope.Options.EnablePrivileges = True" allows me to do the
same type of thing.

I have bene running this code on Win XP SP1, Win XP SP2, Win2003, Win2000
Server under .Net 1.1 without any problems. I have upgraded a few test
machines for .Net 1.1 SP1 and I now have security related problems (access
denied on the watcher start command).

The access deinied is driven by trying to access the "security" logfile.
This may be the case for you. I have used the command

Dim q As New WqlEventQuery( _
"__InstanceCreationEvent", _
New TimeSpan(0, 0, 10), _
"TargetInstance ISA ""Win32_NTLogEvent"" " & _
"and (" & _
"TargetInstance.LogFile = ""Audit Success"" or " & _
"TargetInstance.LogFile = ""Audit Failure"" or " & _
"TargetInstance.LogFile = ""Application"" or " & _
"TargetInstance.LogFile = ""System"" " & _
")")

which explicitly identifies the logfiles of interest (and does not require
EnabledPrivilages to be set to true).

I hope this helps,
Mark
 
Thank you for your answer, and i have tried the
"watcher.Scope.Options.EnablePrivileges = True"
but i still can not access the whole "Win32_NtlogEvent" class,
and i can access Application, System. So strange.

Thank you anyway, hope you can get your answer soon
 
Thank you for your answer, and i have tried the
"watcher.Scope.Options.EnablePrivileges = True"
but i still can not access the whole "Win32_NtlogEvent" class,
and i can access Application, System. So strange.

Thank you anyway, hope you can get your answer soon
 
Hi Janson,

There was another discussion I had on this subject in the
microsoft.public.dotnet.framework group - the subject was

Subject: Problem with .NET 1.1 SP1 - Events

This may help give more details on the subject.

Thanks,
Mark
 
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