Impersonation is the concept whereby an application executes under the \context of the identity of the client that is accessing the \application. This is achieved by using the access token provided by \IIS. Can impersonate entire website by editing the web.config or impersonate chunks of code in the codebehind.Very usefull when accessing folders on a remote server that has no domain

Post Content

Impersonate entire website with web.config
Impersonate in the Code Behind (ASP.NET)
Imports
Script
Impersonate in the Code Behind (C++.NET)
Imports
Script
Calling Impersonate

Impersonate entire website with web.config[-][--][++]

<codebox vbscript><%<identity> Web.config sectionThe <identity> Web.config section defines what identity (Windowsaccount) to use when accessing the ASP.NET application. Here is thegeneric syntax of the <identity> section of the Web.config:<identity impersonate="true|false" userName="username" password="password"/> By default the ASPNET Windows account is used to access ASP.NETresources through the Aspnet_wp.exe process. This account is lesspowerful, compared to the IUSR_ machinename guest Internet account usedby classic ASP for example. In certain situations you might want to usethe anonymous IUSR_ machinename account, as the account accessing yourASP.NET application and you can do that by using the following code inyour Web.config file:<system.web> <identity impersonate="true" /></system.web> In this case we use impersonation. In short impersonation is the act ofASP.NET executing code in the context of an authenticated client(Windows account).If you want you can specify a particular account Windows account to beused instead of the ASPNET Windows account. You can do it like this: <system.web> <identity impersonate="true" userName="WindowsDomain\YourUserName" password="YourPassword" /></system.web> </codebox>

Impersonate in the Code Behind (ASP.NET)[-][--][++]

Imports[-][--][++]

Imports System.Runtime.InteropServices
Imports System.Security.Principal
Imports System.Web.Security

Script[-][--][++]

<codebox vbscript><% Public LOGON32_LOGON_INTERACTIVE As Integer = 2 Public LOGON32_PROVIDER_DEFAULT As Integer = 0 Public impersonationContext As WindowsImpersonationContext Declare Function LogonUserA Lib "advapi32.dll" (ByVal lpszUsername As String,
ByVal lpszDomain As String,
ByVal lpszPassword As String,
ByVal dwLogonType As Integer,
ByVal dwLogonProvider As Integer,
ByRef phToken As IntPtr) As Integer Declare Auto Function DuplicateToken Lib "advapi32.dll" (
ByVal ExistingTokenHandle As IntPtr,
ByVal ImpersonationLevel As Integer,
ByRef DuplicateTokenHandle As IntPtr) As Integer Declare Auto Function RevertToSelf Lib "advapi32.dll" () As Long Declare Auto Function CloseHandle Lib "kernel32.dll" (ByVal handle As IntPtr) As Long Public Sub New() End Sub Public Function impersonateValidUser(ByVal userName As String,
ByVal domain As String, ByVal password As String) As Boolean Dim tempWindowsIdentity As WindowsIdentity Dim token As IntPtr = IntPtr.Zero Dim tokenDuplicate As IntPtr = IntPtr.Zero impersonateValidUser = False If RevertToSelf() Then If LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT, token) <> 0 Then If DuplicateToken(token, 2, tokenDuplicate) <> 0 Then tempWindowsIdentity = New WindowsIdentity(tokenDuplicate) impersonationContext = tempWindowsIdentity.Impersonate() If Not impersonationContext Is Nothing Then impersonateValidUser = True End If End If End If End If If Not tokenDuplicate.Equals(IntPtr.Zero) Then CloseHandle(tokenDuplicate) End If If Not token.Equals(IntPtr.Zero) Then CloseHandle(token) End If End Function Public Sub undoImpersonation() impersonationContext.Undo() End SubEnd Class</codebox>

Impersonate in the Code Behind (C++.NET)[-][--][++]

Imports[-][--][++]

using System.Runtime.InteropServices;
using System.Security.Principal;

Script[-][--][++]

<codebox vbscript><% public const int LOGON32_LOGON_INTERACTIVE = 2; public const int LOGON32_PROVIDER_DEFAULT = 0; WindowsImpersonationContext impersonationContext; [DllImport("advapi32.dll")] public static extern int LogonUserA(String lpszUserName, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet=CharSet.Auto)] public static extern bool CloseHandle(IntPtr handle); private bool impersonateValidUser(String userName, String domain, String password) { WindowsIdentity tempWindowsIdentity; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if(RevertToSelf()) { if(LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref token) != 0) { if(DuplicateToken(token, 2, ref tokenDuplicate) != 0) { tempWindowsIdentity = new WindowsIdentity(tokenDuplicate); impersonationContext = tempWindowsIdentity.Impersonate(); if (impersonationContext != null) { CloseHandle(token); CloseHandle(tokenDuplicate); return true; } } } } if(token!= IntPtr.Zero) CloseHandle(token); if(tokenDuplicate!=IntPtr.Zero) CloseHandle(tokenDuplicate); return false; } private void undoImpersonation() { impersonationContext.Undo(); }</codebox>

Calling Impersonate[-][--][++]

Whatever chunk you want to impersonate, just use

if(impersonateValidUser("administrator", "dyna-web2", "password"))
{
    //do stuff with impersonated users here
}
undoImpersonation();