oxml_xxe

This tool is meant to help test XXE vulnerabilities in OXML document file formats. Currently supported:

• DOCX/XLSX/PPTX
• ODT/ODG/ODP/ODS
• SVG
• XML
• PDF (experimental)
• JPG (experimental)
• GIF (experimental)

BH USA 2015 Presentation:

Exploiting XXE in File Upload Functionality (Slides) (Recorded Webcast)

Blog Posts on the topic:

Exploiting XXE Vulnerabilities in OXML Documents - Part 1

Exploiting CVE-2016-4264 With OXML_XXE

Developer Build

OXML_XXE was re-written in Ruby using Sinatra, Bootstrap, and Haml. Installation should be easy:

• You will need a copy of Ruby. RVM is suggested (https://rvm.io/rvm/install). ruby version 2.1.5 is supported.

• If you are running Ubuntu (or also verified on Kali) you will need a couple of dependencies:

apt-get install libsqlite3-dev libxslt-dev libxml2-dev zlib1g-dev gcc

To install RVM:

gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
\curl -sSL https://get.rvm.io | bash

Install Ruby 2.1.5 with RVM

rvm install 2.1.5
rvm use 2.1.5

Install dependencies and start the server:

cd oxml_xxe
gem install bundler
bundle install
ruby server.rb

Browse to http://127.0.0.1:4567 to get started.

Main Modes

There are two main modes:

Build a File

Build mode adds a DOCTYPE and inserts the XML Entity into the file of the users choice.

String Replace in File

String replacement mode goes through and looks for the symbol § in the document. The XML Entity ("&xxe;") replaces any instances of this symbol. Note, you can open the document in and insert § anywhere to have it replaced. The common use case would be a web application which reads in a xlsx and then prints the results to the screen. Exploiting the XXE it would be possible to have the contents printed to the screen.