Is it possible to duplicate the following credential process in VB.NET?

Answer 1

With your definitions, I use

LogonUser(_username, _domainname, _password, LOGON32_LOGON_NEW_CREDENTIALS, LOGON32_PROVIDER_WINNT50, _tokenHandle)

in my code that is authenticating across the network. I am impersonating a local user on the remote box, as you are. It was so long ago that I don't remember the rationale for using these values, however.

Answer 2

I do a similar thing to map network drives for copying files between machines. I didn't write the code but it's pretty much the same as yours, except for two things:

• After the Impersonate method returns I close both tokens using the CloseHandle routine, before I exit my impersonator method.

• At the top of the impersonator the first thing that happens is a call to RevertToSelf, presumably to cancel any previous impersonation.

I don't know if they would make a difference but it's worth a try. Here are the relevant declarations:

Declare Auto Function CloseHandle Lib "kernel32.dll" (ByVal handle As IntPtr) As Long
Declare Auto Function RevertToSelf Lib "advapi32.dll" () As Long

Answer 3

I have run into this before, and used two different soloution - the easiest was using a third party app: TqcRunas: http://www.quimeras.com/Products/products.asp which allows you to package the required creentials in an encrypted file. However is a pain if the password is forced to expire.

The other solution that I have used is to call a new process with alternative credentials:

        Dim myProcessStartInfo As ProcessStartInfo = New ProcessStartInfo

    With myProcessStartInfo

        .FileName = "file path and name"

        .Domain = "domainname"
        .UserName = "username"

        'password needs to be a SerureString
        Using NewPassword As New Security.SecureString
            With NewPassword
                For Each c As Char In "password".ToCharArray
                    .AppendChar(c)
                Next c
                .MakeReadOnly()
            End With
            .Password = NewPassword.Copy
        End Using

        'UseShellExecute must be false for impersonated process
        .UseShellExecute = False

    End With

    Using Process As New System.Diagnostics.Process
        With Process
            .StartInfo = myProcessStartInfo
            .Start()
        End With
    End Using

Answer 4

See ImpersonationHelper of http://stackoverflow.com/questions/1560732/is-it-possible-to-safely-get-a-securestring-value-from-vb-net/1654058#1654058