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
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