ExcelBanter - Security questions help please

Hi, Peter

As I know, MAC address of the latest Lan adapter can be changeable.
Therefore the protection using MAC address is not perfect.

The following is how to get a MAC address.

Regards,

sjoo
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Option Explicit

Public Const NCBASTAT = &H33
Public Const NCBNAMSZ = 16
Public Const MEM_RESERVE = &H2000
Public Const MEM_COMMIT = &H1000
Public Const MEM_RELEASE = &H8000
Public Const PAGE_READWRITE = &H4
Public Const HEAP_ZERO_MEMORY = &H8
Public Const HEAP_GENERATE_EXCEPTIONS = &H4
Public Const NCBRESET = &H32

Public Type NCB
ncb_command As Byte 'Integer
ncb_retcode As Byte 'Integer
ncb_lsn As Byte 'Integer
ncb_num As Byte ' Integer
ncb_buffer As Long 'String
ncb_length As Integer
ncb_callname As String * NCBNAMSZ
ncb_name As String * NCBNAMSZ
ncb_rto As Byte 'Integer
ncb_sto As Byte ' Integer
ncb_post As Long
ncb_lana_num As Byte 'Integer
ncb_cmd_cplt As Byte 'Integer
ncb_reserve(9) As Byte ' Reserved, must be 0ncb_event As Long
End Type

Public Type ADAPTER_STATUS
adapter_address(5) As Byte 'As String * 6
rev_major As Byte 'Integer
reserved0 As Byte 'Integer
adapter_type As Byte 'Integer
rev_minor As Byte 'Integer
duration As Integer
frmr_recv As Integer
frmr_xmit As Integer
iframe_recv_err As Integer
xmit_aborts As Integer
xmit_success As Long
recv_success As Long
iframe_xmit_err As Integer
recv_buff_unavail As Integer
t1_timeouts As Integer
ti_timeouts As Integer
Reserved1 As Long
free_ncbs As Integer
max_cfg_ncbs As Integer
max_ncbs As Integer
xmit_buf_unavail As Integer
max_dgram_size As Integer
pending_sess As Integer
max_cfg_sess As Integer
max_sess As Integer
max_sess_pkt_size As Integer
name_count As Integer
End Type

Public Type NAME_BUFFER
name As String * NCBNAMSZ
name_num As Integer
name_flags As Integer
End Type

Public Type ASTAT
adapt As ADAPTER_STATUS
NameBuff(30) As NAME_BUFFER
End Type

Public Declare Function Netbios Lib "netapi32.dll" _
(pncb As NCB) As Byte

Public Declare Sub CopyMemory Lib "kernel32" Alias _
"RtlMoveMemory" (hpvDest As Any, ByVal hpvSource As Long, _
ByVal cbCopy As Long)

Public Declare Function VirtualAlloc Lib "kernel32" (lpAddress As Long,
_
ByVal dwSize As Long, ByVal flAllocationType As Long, _
ByVal flProtect As Long) As Long

Public Declare Function VirtualFree Lib "kernel32" (lpAddress As Any, _
ByVal dwSize As Long, ByVal dwFreeType As Long) As Long

Public Declare Function GetProcessHeap Lib "kernel32" () As Long

Public Declare Function HeapAlloc Lib "kernel32" (ByVal hHeap As Long,
_
ByVal dwFlags As Long, ByVal dwBytes As Long) As Long

Public Declare Function HeapFree Lib "kernel32" (ByVal hHeap As Long, _
ByVal dwFlags As Long, lpMem As Any) As Long

Public Function getMac() As String
Dim myNcb As NCB
Dim bRet As Byte

myNcb.ncb_command = NCBRESET
bRet = Netbios(myNcb)
myNcb.ncb_command = NCBASTAT
myNcb.ncb_lana_num = 0
myNcb.ncb_callname = "* "

Dim myASTAT As ASTAT, tempASTAT As ASTAT
Dim pASTAT As Long

myNcb.ncb_length = Len(myASTAT)

Debug.Print ERR.LastDllError
pASTAT = HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS Or _
HEAP_ZERO_MEMORY, myNcb.ncb_length)

If pASTAT = 0 Then
Debug.Print "memory allcoation failed!"
Exit Function
End If

myNcb.ncb_buffer = pASTAT
bRet = Netbios(myNcb)
Debug.Print ERR.LastDllError
CopyMemory myASTAT, myNcb.ncb_buffer, Len(myASTAT)
getMac = myASTAT.adapt.adapter_address(0) & "." & _
myASTAT.adapt.adapter_address(1) _
& "." & myASTAT.adapt.adapter_address(2) & "." & _
myASTAT.adapt.adapter_address(3) _
& "." & myASTAT.adapt.adapter_address(4) & "." & _
myASTAT.adapt.adapter_address(5)

' MsgBox myASTAT.adapt.adapter_address(0) & " " & _
' myASTAT.adapt.adapter_address(1) _
' & " " & myASTAT.adapt.adapter_address(2) & " " & _
' myASTAT.adapt.adapter_address(3) _
' & " " & myASTAT.adapt.adapter_address(4) & " " & _
' myASTAT.adapt.adapter_address(5)

' MsgBox Hex(myASTAT.adapt.adapter_address(0)) & " " & _
' Hex(myASTAT.adapt.adapter_address(1)) _
' & " " & Hex(myASTAT.adapt.adapter_address(2)) & " " & _
' Hex(myASTAT.adapt.adapter_address(3)) _
' & " " & Hex(myASTAT.adapt.adapter_address(4)) & " " & _
' Hex(myASTAT.adapt.adapter_address(5))

HeapFree GetProcessHeap(), 0, pASTAT

End Function