Microsoft KB Archive/187535

= How To Change Passwords Programmatically in Windows NT =

Article ID: 187535

Article Last Modified on 7/15/2004

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APPLIES TO


 * Microsoft Visual Basic 6.0 Learning Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition
 * Microsoft Visual Basic 5.0 Control Creation Edition
 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 4.0 32-Bit Enterprise Edition

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This article was previously published under Q187535



SUMMARY
This article describes how to change passwords on accounts in Windows NT or Windows 2000 using Visual Basic.



MORE INFORMATION
WARNING: One or more of the following functions are discussed in this article; VarPtr, VarPtrArray, VarPtrStringArray, StrPtr, ObjPtr. These functions are not supported by Microsoft Technical Support. They are not documented in the Visual Basic documentation and are provided in this Knowledge Base article "as is." Microsoft does not guarantee that they will be available in future releases of Visual Basic:

There are several considerations that apply when changing passwords:
 * Net function calls are Unicode only. All strings passed to and returned by these functions are in Unicode form.
 * When targeting a domain controller for account update operations, be sure to target the primary domain controller for the domain. The account settings are replicated by the primary domain controller to each backup domain controller as appropriate. The NetGetDCName function call can be used to get the primary domain controller computer name from a domain name.
 * If the caller is an administrator or account operator on the target machine/domain, the NetUserSetInfo function call at info-level 1003 can be used to override the existing password. The caller does not need to know the existing password. Note that passwords can be provided for accounts during account creation time using NetUserAdd.
 * If the caller is a non-administrator on the target machine/domain, the NetUserChangePassword function call can be used to override the existing password. In order for this call to succeed, the caller must supply the correct current password. NetUserChangePassword behaves differently than other Net function calls with respect to the first parameter that specifies either a domain name or machine name. If this parameter is NULL, the domain name of the caller is used. Keep this in mind if you intend to change passwords on accounts outside the domain of the logged-on caller. You should explicitly provide the target domain name.

Creating the Project
 Start a new Visual Basic Standard EXE Project, Form1 is created by default.  Add four labels, four text boxes, and two command buttons to Form1 with the following captions:

     Name        Caption -            Label1       UserName: Label2      Machine/Domain: Label3      Old Password: Label4      New Password: txtUser txtMachine txtOld txtNew cmdOK       &OK cmdClose    &Close  Set the Passwordchar property of txtOld and txtNew to "*".  Paste the following code into the declarations section of Form1: Option Explicit

Const FORMAT_MESSAGE_FROM_HMODULE = &H800 Const FORMAT_MESSAGE_FROM_SYSTEM = &H1000

Const NERR_BASE = 2100 Const MAX_NERR = NERR_BASE + 899 ' This is the last error in                                    ' NERR   range. Const LOAD_LIBRARY_AS_DATAFILE = &H2

Private Declare Function LoadLibraryEx Lib "kernel32" Alias _ "LoadLibraryExA" (ByVal lpLibFileName As String, _      ByVal hFile As Long, ByVal dwFlags As Long) As Long

Private Declare Function FreeLibrary Lib "kernel32" _ (ByVal hLibModule As Long) As Long

Private Declare Function NetApiBufferFree& Lib "netapi32" _ (ByVal Buffer As Long)

Private Declare Sub lstrcpyW Lib "kernel32" _ (dest As Any, ByVal src As Any)

Private Declare Function FormatMessage Lib "kernel32" Alias _ "FormatMessageA" (ByVal dwFlags As Long, _      ByVal lpSource As Long, _       ByVal dwMessageId As Long, _       ByVal dwLanguageId As Long, ByVal lpBuffer As String, _       ByVal nSize As Long, Arguments As Any) As Long

Private Declare Function NetUserSetInfo Lib "netapi32.dll" _ (ByVal ServerName As String, ByVal Username As String, _      ByVal Level As Long, UserInfo As Any, ParmError As Long) As Long

Private Declare Function NetGetDCName Lib "netapi32.dll" ( _      ServerName As Long, domainname As Byte, bufptr As Long) As Long

Private Declare Function NetUserChangePassword Lib "netapi32.dll" ( _      ByVal domainname As String, ByVal Username As String, _       ByVal OldPassword As String, ByVal NewPassword As String) As Long

Private Type USER_INFO_1003 usri1003_password As Long End Type

Private Sub cmdClose_Click Unload Me   End Sub

Private Sub cmdOK_Click Dim sServer As String, sUser As String Dim sNewPass As String, sOldPass As String Dim UI1003 As USER_INFO_1003 Dim dwLevel As Long Dim lRet As String Dim sNew As String

' StrConv Functions are necessary since VB will perform ' UNICODE/ANSI translation before passing strings to the NETAPI ' functions

MousePointer = vbHourglass sUser = StrConv(txtUser, vbUnicode) sNewPass = StrConv(txtNew, vbUnicode)

'See if this is Domain or Computer referenced If Left(txtMachine, 2) = "\\" Then sServer = StrConv(txtMachine, vbUnicode) Else ' Domain was referenced, get the Primary Domain Controller sServer = StrConv(GetPrimaryDCName(txtMachine), vbUnicode) End If

If txtOld = "" Then ' Administrative over-ride of existing password. ' Does not require old password

dwLevel = 1003 sNew = txtNew UI1003.usri1003_password = StrPtr(sNew) lRet = NetUserSetInfo(sServer, sUser, dwLevel, UI1003, 0&) Else ' Set the Old Password and attempt to change the user's password sOldPass = StrConv(txtOld, vbUnicode) lRet = NetUserChangePassword(sServer, sUser, sOldPass, sNewPass) End If

MousePointer = vbDefault If lRet <> 0 Then DisplayError lRet Else MsgBox "Password Change was Successful" End If

End Sub Private Sub DisplayError(ByVal lCode As Long) Dim sMsg As String Dim sRtrnCode As String Dim lFlags As Long Dim hModule As Long Dim lRet As Long

hModule = 0 sRtrnCode = Space$(256) lFlags = FORMAT_MESSAGE_FROM_SYSTEM

' if lRet is in the network range, load the message source

If (lCode >= NERR_BASE And lCode <= MAX_NERR) Then hModule = LoadLibraryEx("netmsg.dll", 0&, _                     LOAD_LIBRARY_AS_DATAFILE)

If (hModule <> 0) Then lFlags = lFlags Or FORMAT_MESSAGE_FROM_HMODULE End If

End If

' Call FormatMessage to allow for message text to be acquired ' from the system or the supplied module handle. '

lRet = FormatMessage(lFlags, hModule, lCode, 0&, _                            sRtrnCode, 256&, 0&) If lRet = 0 Then MsgBox "FormatMessage Error : " & Err.LastDllError End If

' if you loaded a message source, unload it. '       If (hModule <> 0) Then FreeLibrary (hModule) End If

'//... now display this string sMsg = "ERROR: " & lCode & " - " & sRtrnCode

MsgBox sMsg

End Sub Public Function GetPrimaryDCName(ByVal DName As String) As String

Dim DCName As String, DCNPtr As Long Dim DNArray As Byte, DCNArray(100) As Byte Dim result As Long

DNArray = DName & vbNullChar ' Lookup the Primary Domain Controller result = NetGetDCName(0&, DNArray(0), DCNPtr) If result <> 0 Then Msgbox "Error: " & result Exit Function End If      lstrcpyW DCNArray(0), DCNPtr result = NetApiBufferFree(DCNPtr) DCName = DCNArray GetPrimaryDCName = Left(DCName, InStr(DCName, Chr(0)) - 1)

End Function  Run the Application.

Keywords: kbhowto kbnetwork KB187535

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