Overview
This is a continuation of my articles on the TCPUtil code. The origional control was designed to simplify socket communications from within a scripting environment. This time round I decided to simplify the code further by re-writing the ActiveX control that handles the socket connections to also handle connection timeouts. In a scripting context this is the most difficult aspect of socket programming, because one has to include complex tests in a script to handle the timeouts appropriately. I also wanted to obvaite the need for relying on events (which the previous version did) because this made the code unnececarily complex.
As an example of the new ActiveX control I am going to show you how simple it is to retrieve real-time currency conversion information from the XE Converter programmatically using the control.
Previous articles in this series:
Scripting Internet Connections Under Window$
Search Engine submission 'exploit'
Google 'exploit' - TCPUtil pt III
Cloaked Exploit Scanner Part I and Part II
Instantiation of the control
First compile and register the ntsa.ocx control (source is included in the zip file at the end of this tutorial). If you don't have a copy of VB6 to compile the control you can use the pre-compiled version that is also included in the zip file.
When you have compiled the control (or if you are just using the one included in the zip) you will need to register the control with regsvr32 (ie regsvr32 c:\path\ntsa.ocx where c:\path is the full path to the ocx file.)
Now the control is registered you can include it in you scripts like this:
Using the TCPUtil ActiveXCode:'Load an instance of the control
Set tcputil =WScript.CreateObject("ntsa.tcputil")
Once you have an instance of the control in your script you can use the following methods to connect and send data to the server. All timouts are handled from within the control, returning control to the calling application when appropriate. Because of this the control is ideal for performing IP operations from within a scripting environment where the main battle is ensuring that your script does not terminate prematurely.
The XE Converter example scriptCode:' Set connection time out (in milliseconds)
tcputil.ConnectionTimeout = 2000
' Set time out for inactivity (in milliseconds)
tcputil.GetDataTimeout = 1000
'Set the server that we wish to connect to
tcputil.RemoteHost = "127.0.0.1"
'Set the port we are going to connect on
tcputil.RemotePort = 80
'Attempt a connection
If tcputil.IPConnect Then
'Connected sucsessfully
'Loop while connected
'This is so you can test a connection
'in a stated environment (ie pop3/smtp/etc)
Do While tcputil.Connected
'Fill the read buffer with the results
'of the PostStr query
tcputil.GetBuffer CStr("GET / HTTP/1.1" & VBCRLF & "HOST:www.myweb.co.uk" & vbcrlf & vbcrlf)
'Read the contents of the buffer
HTML = tcputil.ReadBuffer
'Empty the buffer
'(You need to do this before issuing
'further commands in a stated service)
tcputil.ClearBuffer
'Close the Socket
'(But you could send more if the service
'you are connecting to is stated)
tcputil.IPClose
'Loop until the socket is closed
Loop
end if
This script is designed for use in the Windows script host. I have also included this vbs file in the zip file at the end of this tutorial. Usage is as follows:
Quote:
Usage: xtcputil
[--Amount|-a] Amount to convert
[--From|-f] convert from currency
[--To|-t] Convert to currency
[--Help|/?]>
Code:Dim PostStr, Pst
Dim HTML
Dim Amount, cFrom, cTo
WScript.Echo "-- XE Converter Hack."
WScript.Echo "-- by NTSA 2002"
WScript.Echo "-- www.ntsa.org.uk"
WScript.Echo ""
'Load an instance of the control
Set tcputil =WScript.CreateObject("ntsa.tcputil")
'Check for errors
if err.number > 0 then
WScript.Echo "Could not create an instance of the TCPUtil control."
WScript.Echo "You need to register ntsa.ocx using the regsvr32"
WScript.Echo "command. (ie regsvr32 c:\path\ntsa.ocx where c:\path"
WScript.Echo "is the full path to the ocx file.)",flgEcho
wscript.quit
end if
'Get user input from the command line
Set oArgs = WScript.Arguments
ArgNum = 0
While ArgNum < oArgs.Count
Select Case RemoveDel(LCase(oArgs(ArgNum)))
Case "amount","a":
ArgNum = ArgNum + 1
amount = oArgs(ArgNum)
Case "from","f":
ArgNum = ArgNum + 1
cFrom = oArgs(ArgNum)
Case "to","t":
ArgNum = ArgNum + 1
cTo = oArgs(ArgNum)
Case "help","?":
DisplayUsage
wscript.quit
End Select
ArgNum = ArgNum + 1
Wend
'Check that we have all the required parameters
if isempty(Amount) or isempty(cFrom) or isempty(cTo) then
'Else quit
wscript.echo "Missing parameter"
DisplayUsage
end if
'Output the conversion using the convert function
wscript.echo amount & " " & ucase(cfrom) & " = " & convert & " " & ucase(cto)
function Convert
'PST is the data we are actually posting
Pst = "Amount=" & Amount & "&From=" & UCase(cFrom) & "&To=" & UCase(cTo)
'Build the string that we are going to send
PostStr = ""
PostStr = PostStr & "POST /ucc/convert.cgi HTTP/1.1" & vbCrLf
PostStr = PostStr & "Accept-Language: en-gb" & vbCrLf
PostStr = PostStr & "Content-Type: application/x-www-form-urlencoded" & vbCrLf
PostStr = PostStr & "Accept-Encoding: gzip, deflate" & vbCrLf
PostStr = PostStr & "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" & vbCrLf
PostStr = PostStr & "Host: www.xe.com" & vbCrLf
'Set the content length according to the length of PST
PostStr = PostStr & "Content-Length: " & CStr(Len(Pst)) & vbCrLf
PostStr = PostStr & "Connection: Keep-Alive" & vbCrLf
PostStr = PostStr & "Cache-Control: no-cache" & vbCrLf
PostStr = PostStr & "" & vbCrLf
PostStr = PostStr & Pst & vbCrLf & vbCrLf
' Set connection time out (in milliseconds)
tcputil.ConnectionTimeout = 2000
' Set time out for inactivity (in milliseconds)
tcputil.GetDataTimeout = 1000
'Set the server that we wish to connect to
tcputil.RemoteHost = "216.220.38.20"
'Set the port we are going to connect on
tcputil.RemotePort = 80
'Attempt a connection
If tcputil.IPConnect Then
'Connected sucsessfully
'Loop while connected
'This is so you can test a connection
'in a stated environment (ie pop3/smtp/etc)
Do While tcputil.Connected
'Fill the read buffer with the results
'of the PostStr query
tcputil.GetBuffer CStr(PostStr)
'Read the contents of the buffer
HTML = tcputil.ReadBuffer
'Empty the buffer
'(You need to do this before issuing
'further commands in a stated service)
tcputil.ClearBuffer
'Close the Socket
tcputil.IPClose
'Loop until the socket is closed
Loop
'This is where it gets dirty -
'We want to cut a certain section
'out of the returned html with
'split commands.
Dim flds
If Len(HTML) > 0 Then
flds = Split(HTML, "<!XERC-UCC2-P1.4-R1>")
HTML = LCase(flds(1))
flds = Split(HTML, "</tr")
HTML = flds(0)
flds = Split(HTML, "<td")
HTML = flds(6)
flds = Split(HTML, "")
HTML = flds(1)
flds = Split(HTML, "")
HTML = flds(0)
HTML = Left(Trim(HTML), Len(HTML) - 4)
convert = HTML
Else
wscript.echo "An error occured."
wscript.echo "CConvert", "No data returned"
End If
Else
wscript.echo "An error occured."
wscript.echo "CConvert", "Could not connect"
End If
end function
Sub DisplayUsage
WScript.Echo "Usage: xtcputil"
WScript.Echo " [--Amount|-a] Amount to convert"
WScript.Echo " [--From|-f] convert from currency"
WScript.Echo " [--To|-t] Convert to currency"
WScript.Echo " [--Help|/?]>"
WScript.Echo ""
WScript.Quit (1)
End Sub
function RemoveDel(str)
RemoveDel = replace(str,"/","")
RemoveDel = replace(RemoveDel,"-","")
RemoveDel = replace(RemoveDel,"--","")
end function
function IsEmpty(str)
if str & "" = "" then
isempty = true
else
isempty = false
end if
end function
