MicroGuestBook Remote XSS Attack

.:. MicroGuestBook Remote XSS Bug .:.

Date:

July 2006, 22

Product:

MicroGuestBook Latest Version

Vendor:

http://www.phptoys.com

Description:

Micro guestbook is a MySQL based guestbook script with a CSS based attractive interface. It can store the name, date,
message, location, web and email information of the visitor.

Exploit(s)/Advisory(ies):

The application is vulnerable to a Remote XSS Bug. The field 'name' and 'comment' are not properly sanitized before being
used, so a malicious people can exploit this vulnerability to inject arbitrary HTML and script code.

If you look the code in add.php you can see:

[…]

if (isset($_POST['submitBtn'])) {
$name = (isset($_POST['name'])) ? $_POST['name'] : '' ;
$comment = (isset($_POST['comment'])) ? $_POST['comment'] : '' ;
$location = (isset($_POST['location'])) ? $_POST['location'] : '' ;
$website = (isset($_POST['website'])) ? $_POST['website'] : '' ;
$email = (isset($_POST['email'])) ? $_POST['email'] : '' ;
$actDate = date("Y-m-d H:i:s");

     //Minimum name and comment length.
     if ((strlen($name) > 2) && (strlen($comment) > 5)){
         $sql = "INSERT INTO guestbook (name,text,insertdate,location,web,email) VALUES (";
         $sql .= "'".$name."','".$comment."','".$actDate."','".$location."','".$website."','".$email."')";
         $MyDb->f_ExecuteSql($sql);

[…]

And in index.php you will see:

[…]

<div id="name"><?php echo $row['name']; ?></div>
<div id="info">
<div id="infoicons">
<?php
if (strlen($row['web']) > 5) echo '<a href="http://'.$row['web'].'"><img src="style/www.gif"></a>';
if (strlen($row['email']) > 5) echo '<a href="mailto:'.$row['email'].'"><img src="style/mail.gif"></a>';
?>
</div>
<div id="infodate"><?php echo $row['insertdate']; ?></div>
</div>
</div>
<div id="base">
<div id="icon"><?php echo $row['location']; ?></div>
<div id="text"><?php echo nl2br($row['text']); ?></div>

[…]

PoC(s):

You can put your own HTML or script code in the field name or comment. Try:

<script>alert("XSS")</script>

Vendor Status:

[July 2006, 22] Vendor contacted!

Patches:

[July 2006, 22] At the moment there is no patch available from the vendor. You can take a look at this site if a patch will
be posted up:

http://www.phptoys.com

If you don't wanna wait, edit the source code to ensure that input is properly sanitised.

Credits:

omnipresent
omnipresent[at]email[dot]it
http://it.security.netsons.org