WordPress Users Ultra Plugin [Blind SQL injection] - Update

* Exploit Title: WordPress Users Ultra Plugin [Blind SQL injection]
* Discovery Date: 2015/10/19
* Public Disclosure Date: 2015/12/01
* Exploit Author: Panagiotis Vagenas
* Contact: https://twitter.com/panVagenas
* Vendor Homepage: http://usersultra.com
* Software Link: https://wordpress.org/plugins/users-ultra/
* Version: 1.5.50
* Tested on: WordPress 4.3.1
* Category: webapps

Description
============================================================
====================

One can perform an SQL injection attack simply by exploiting the
following WP ajax actions:

1. `edit_video`
2. `delete_photo`
3. `delete_gallery`
4. `delete_video`
5. `reload_photos`
6. `edit_gallery`
7. `edit_gallery_confirm`
8. `edit_photo`
9. `edit_photo_confirm`
10. `edit_video_confirm`
11. `set_as_main_photo`
12. `sort_photo_list`
13. `sort_gallery_list`
14. `reload_videos`

POST parameters that are exploitable in each action respectively:

1. `video_id`
2. `photo_id`
3. `gal_id`
4. `video_id`
5. `gal_id`
6. `gal_id`
7. `gal_id`
8. `photo_id`
9. `photo_id`
10. `video_id`
11. `photo_id`, `gal_id`
12. `order`
13. `order`
14. `video_id`

In case #7 a user can also change the gallery name, description and
visibility by setting POST parameters `gal_name`, `gal_desc` and
`gal_visibility` respectively.

In case #8 `photo_id` is first casted to integer and a query to DB is
performed. If results are returned then for each result a new query is
performed without casting the `photo_id` to integer. So if an attacker
knows a valid video id then it can perform the attack in the second
query. This achievable because `<?php (int)'1 and sleep(5)' === 1; ?>

In case #9 a user can also change the photo name, description, tags and
category by setting POST parameters `photo_name`, `photo_desc`,
`photo_tags` and `photo_category` respectively.

In case #10 a user can also change the video name, unique id and type by
setting POST parameters `video_name`, `video_unique_id` and `video_type`
respectively.

Because function wpdb::get_results() and wpdb::query() are in use here,
only one SQL statement can be made per request. This holds severity of
the attack low.
In addition all actions are privileged so the user must have an active
account in vulnerable website, in order to perform the attack.


PoC
================================================================================

Send a post request to
`http://my.vulnerable.website.com/wp-admin/admin-ajax.php` with data:
`action=edit_video&video_id=1 and sleep(5) `

Timeline
================================================================================

2015/10/29 - Vendor notified via email
2015/11/11 - Vendor notified via contact form in his website
2015/11/13 - Vendor notified via support forums at wordpress.org
2015/11/14 - Vendor responded and received report through email
2015/12/08 - Vendor provided new version 1.5.63 which resolves issues

Solution
================================================================================

Upgrade to version 1.5.63