A.D.TEJPAL
adtp at airtelbroadband.in
Wed Apr 26 23:51:19 CDT 2006
Marty,
Really amazing, the way you come up with such gems. Thanks again.
A.D.Tejpal
---------------
----- Original Message -----
From: MartyConnelly
To: Access Developers discussion and problem solving
Sent: Thursday, April 27, 2006 01:29
Subject: Re: [AccessD] DBEngine.CompactDatabase - Supplying Passwordargumentfor currently open db.
I knew I had it somewhere from a couple of years ago, this works for
Access 2000-2003
They use an XOR on the file creation datestamp, now this method may not work in some situations like an mde or an encrypted file, I haven't checked.
Now everyone should know this method of security is easily circumvented.
so I am posting it here. Variations of this code are available on the web.
Dim NullDate As Date
Private Declare Function GetTempPath Lib "kernel32.dll" Alias
"GetTempPathA" (ByVal nBufferLength As Long, _
ByVal lpBuffer As String) As Long
Private Declare Function GetTempFileName Lib "kernel32.dll" Alias
"GetTempFileNameA" (ByVal lpszPath As String, _
ByVal lpPrefixString As String, ByVal wUnique As Long, ByVal
lpTempFileName As String) As Long
Private Type FILETIME
dwLowDateTime As Long
dwHighDateTime As Long
End Type
Private Type BY_HANDLE_FILE_INFORMATION
dwFileAttributes As Long
ftCreationTime As FILETIME
ftLastAccessTime As FILETIME
ftLastWriteTime As FILETIME
dwVolumeSerialNumber As Long
nFileSizeHigh As Long
nFileSizeLow As Long
nNumberOfLinks As Long
nFileIndexHigh As Long
nFileIndexLow As Long
End Type
Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type
Private Const OFS_MAXPATHNAME = 128
Private Const OF_READ = &H0
Private Type OFSTRUCT
cBytes As Byte
fFixedDisk As Byte
nErrCode As Integer
Reserved1 As Integer
Reserved2 As Integer
szPathName(OFS_MAXPATHNAME) As Byte
End Type
Private Declare Function GetFileInformationByHandle Lib "kernel32"
(ByVal hfile As Long, lpFileInformation As _
BY_HANDLE_FILE_INFORMATION) As Long
Private Declare Function FileTimeToSystemTime Lib "kernel32" (lpFileTime
As FILETIME, lpSystemTime As _
SYSTEMTIME) As Long
Private Declare Function FileTimeToLocalFileTime Lib "kernel32"
(lpFileTime As FILETIME, lpLocalFileTime As _
FILETIME) As Long
Private Declare Function OpenFile Lib "kernel32" (ByVal lpFileName As
String, lpReOpenBuff As OFSTRUCT, _
ByVal wStyle As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As
Long) As Long
Public Function GetFileDate(File As String) As Date
Dim fhi As BY_HANDLE_FILE_INFORMATION
Dim ctime As FILETIME, atime As FILETIME, wtime As FILETIME
Dim ftime As SYSTEMTIME
Dim buff As OFSTRUCT
Dim rval As Long, hfile As Long
hfile = OpenFile(File, buff, OF_READ)
If hfile = -1 Then
GetFileDate = NullDate
Else
GetFileInformationByHandle hfile, fhi
ctime = fhi.ftCreationTime
'Convert File Time Zone to Local
rval = FileTimeToLocalFileTime(ctime, ctime)
'Convert File Time Format to System Time Format
rval = FileTimeToSystemTime(ctime, ftime)
GetFileDate = ftime.wDay & "/" & ftime.wMonth & "/" & ftime.wYear & " "
& ftime.wHour & ":" & ftime.wMinute & ":" & ftime.wSecond
End If
CloseHandle hfile
End Function
Public Function GuessAccess2000Password(ProtectedFile As String) As String
' The trick of this function is that Access 2000 codifies your password by
' making the XOR of it and a mask. I don't know the algorithm to get
this mask
' but I do know that it only depends on the creation date of the database.
' So the proccess is: create a dummy database with the same date as the
protected
' database, and then make the XOR of the encrypted bytes of the
protected database
' and the password-less database we create in this process.
Dim n As Long, s1 As String * 1, s2 As String * 1
Dim Password As String
Dim x1 As Byte, x2 As Byte
Dim TempFile As String
Dim DateFile As Date, PreviousDate As Date
Dim Handle1 As Long, Handle2 As Long
' Get the creation date of the protected database
DateFile = GetFileDate(ProtectedFile)
If DateFile = NullDate Then
GuessAccess2000Password = "Can't open database file. Maybe you have it
open in exclusive mode"
Exit Function
End If
' Create a temporary file in the Temp directory of windows
TempFile = TempPath & "temp.mdb"
' Remove the temporary file if it exists
If Dir(TempFile) <> "" Then
Kill TempFile
End If
' Keep the system date, then set it to the same date as the protected
database
PreviousDate = Date
Date = DateFile
' Create the database, which will have so the same date as the protected
database
CreateDatabase TempFile, dbLangGeneral
' We can restore now the real date
Date = PreviousDate
Handle1 = FreeFile
Open TempFile For Binary As #Handle1
Handle2 = FreeFile
Open ProtectedFile For Binary As #Handle2
Password = ""
Seek #Handle1, &H43
Seek #Handle2, &H43
' The maximum length of the password is 20 characters
For n = 0 To 19
x1 = Asc(Input(1, Handle1))
x2 = Asc(Input(1, Handle2))
If x1 <> x2 Then
Password = Password & Chr(x1 Xor x2)
End If
' We skip the even positions, because the password is stored using
' two bytes per character
x1 = Asc(Input(1, Handle1))
x2 = Asc(Input(1, Handle2))
Next
Close 1
Close 2
Kill TempFile
GuessAccess2000Password = Password
End Function
Private Function TempPath() As String
' Generate a temporary file path to ?????.TMP, where (path)
' is Windows's temporary file directory and ???? is a randomly assigned
unique value.
' Then display the name of the created file on the screen.
Dim Path As String ' receives name of temporary file path
Dim TempFile As String ' receives name of temporary file
Dim slength As Long ' receives length of string returned for the path
Dim lastfour As Long ' receives hex value of the randomly assigned ????
' Get Windows's temporary file path
Path = Space(255) ' initialize the buffer to receive the path
slength = GetTempPath(255, Path) ' read the path name
TempPath = Left(Path, slength) ' extract data from the variable
End Function
Sub testit()
' NOte 1: Put a reference to Microsoft DAO 3.6
' Note 2: You cannot have the database opened in exclusive mode while
you execute this procedure
Debug.Print GuessAccess2000Password("C:\Access files\Security\Access
2003 Security Macro\Macro security for runtime.mdb")
End Sub
A.D.TEJPAL wrote:
> My sincere thanks Marty! I shall explore the feasibility of adapting it to current version.
>
>A.D.Tejpal
>---------------
>
> ----- Original Message -----
> From: MartyConnelly
> To: Access Developers discussion and problem solving
> Sent: Wednesday, April 26, 2006 01:32
> Subject: Re: [AccessD] DBEngine.CompactDatabase - Supplying Passwordargument for currently open db.
>
>
> For 97 this was easy
> http://www.trigeminal.com/code/DatabasePassword.bas
>
>
> A.D.TEJPAL wrote:
>
> > For making a back-up copy of currently open FE and then compacting this back-up copy, using DBEngine.CompactDatabase method, database password if existing, has to be passed as the last argument, e.g.
> >
> > DBEngine.CompactDatabase "SourceFilePath", _
> > "DestinationFilePath", , , ";pwd=xyz"
> >
> > Could there be a way to get the password for currently open db, without prompting the user for it ?
> >
> > Note - Application.CompactRepair method seems ruled out as it does not have any password argument in its syntax and instead prompts the user for it.
> >
> >TIA
> >A.D.Tejpal
> >---------------