==================================================================== Advisory by Eye On Security Research Group - India www.eos-india.net ==================================================================== 1...............................................................Product 2................................................................Vendor 3.........................................................Vulnerability 4.........................................................About Product 5..............................................Details of vulnerability 6...............................................................Exploit 7..............................................................Solution 8...............................................................Credits 1. Product ========== miniBB 1.7 (latest) and earlier 2. Vendor ========= www.minibb.net 3. Vulnerability ================ Cross Site Scripting vulnerability in bb_func_usernfo.php 4. About miniBB =============== (direct quote from www.minibb.net) miniBB ("minimalistic bulletin board") is flat linear (non-tree) version of highly customizable bulletin board. It inherits most popular features from the bulletin boards the planet has at this moment, with one exception: it is very small by size (2-5 times smaller than usual boards), very fast and FREE. Mostly miniBB is designed for small and medium Internet-sites, but also can be used in large projects. 5. Details of vulnerability =========================== bb_func_usernfo.php contains code to take data from "minibb_users" table and display information about a particular user requested. The code for displaying website of the any user in bb_func_usernfo.php is as follow : if ($row[6]!='') $row[6]='<a href="'.$row[6].'" target="_blank">'.$row[6].'</a>'; else $row[6]=''; So an attacker can create a login in the forums and in the preferences, give his website name as http://blah.com"></a><script>somejavascriptcode</script> Hence when others will try to view his profile, the inserted javascript code will be executed. The actual bug lies in the "bb_edit_prf.php" file where the website name inserted by a user in his preferences is not validated properly. 6. Exploit ========== Create a user in the forums with your website name as http://blah.com"></a><script>alert(document.cookie)</script> Now suppose your userid is 5, then just clicking http://[target]/index.php?action=userinfo&user=5 will execute the script. 7. Solution =========== Check for the validation of the user data while editing his preferences in the "bb_edit_prf.php" file and filter out strings like "<script>", quotes, "cookie" etc. 8. Credits ========== Chintan Trivedi - http://www.hackersprogrammers.com "Eye on Security Research Group - India " - www.eos-india.net