Website Link Injection

Question

I have a website that is fairly static. It has some forms on it to send in contact information, mailing list submissions, etc. Perhaps hours/days after an upload to the site I found that the main index page had new code in it that I had not placed there that contained a hidden bunch of links in a invisible div.

I have the following code the handles the variables sent in from the form.

<?php
// PHP Mail Order to [email protected] w/ some error detection.

    $jamemail = "[email protected]";
    function check_input($data, $problem='')
        {
        $data = trim($data);
        $data = stripslashes($data);
        $data = htmlspecialchars($data);
        if ($problem && strlen($data) == 0)
            {
            die($problem);
            }
        return $data;
        }
    $email    = check_input($_POST['email'], "Please input email address.");
    $name    = check_input($_POST['name'], "Please input name.");

    mail($jamemail, "Mailing List Submission", "Name: " . $name . " Email: " .$email);
    header('Location: index.php');
?>

I have the following code within the index page to present the form with some Javascript to do error detection on the content of the submission prior to submission.

    <form action="sendlist.php" method="post" onSubmit="return checkmaill(this);">
        <label for="name"><strong>Name: </strong></label>
        <input type="text" name="name"/><br />
        <label for="email"><strong>Email: </strong></label>
        <input type="text" name="email"/><br />
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="submit" value="Subscribe" style="width: 100px;"/>
    </form>

At the end of the day, the source code where the injected hyperlinks is as follows:

</body>

</html><!-- google --><font style="position: absolute;overflow: hidden;height: 0;width: 0">    
xeex172901
<a href=http://menorca.caeb.com/od9c2/xjdmy/onondaga.php&gt;onondaga&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/tami.php&gt;tami&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/shotguns.php&gt;shotguns&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/weir.php&gt;weir&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/copperhead.php&gt;copperhead&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/mpv.php&gt;mpv&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/brunei.php&gt;brunei&lt;/a&gt;
<a href=http://menorca.caeb.com/od9c2/xjdmy/doreen.php&gt;doreen&lt;/a&gt;

Answer 1

It seems highly unlikely that your form has anything to do with your problem, more likely your ftp information has been compromised. Assuming that you use ftp to upload changes to your web-site...

Answer 2

Unless someone has physical access to your server, there is a missing piece here. Are you sure this is the only server side code that runs?

You don't need a post request to be vulnerable. XSS comes in all shapes and sizes.

Answer 3

I suggest you to upgrade your wordpress

I found another site still effected with same inject code here, they using wordpress and have contact form there too.

By the way, the page you show us is after redirected page, vulnerabilty could be in contact.php or in wordpress.

Answer 4

The webhosting server is hacked, instead of a mass-deface = Replacing indexes with "IPWND!U" they just choose to spread viruses and use blackhad seo for other domains they have in control, I recomend you change your hosting.