WSUSpect Proxy

Written by Paul Stone and Alex Chapman, Context Information Security

Summary

This is a proof of concept script to inject 'fake' updates into non-SSL WSUS traffic. It is based on our BlackHat USA 2015 presentation, 'WSUSpect – Compromising the Windows Enterprise via Windows Update'

• White paper: http://www.contextis.com/documents/161/CTX_WSUSpect_White_Paper.pdf
• Slides: http://www.contextis.com/documents/162/WSUSpect_Presentation.pdf

Prerequisites

You'll need the Python Twisted library installed. You can do this by running:

pip install twisted

You also need to place a Microsoft-signed binary (e.g. PsExec) into the payloads directory. This script has been tested on Python 2.7. It does not yet work with Python 3.x; contributions are welcome.

Usage

To test this out, you'll need a target Windows 7 or 8 machine that is configured to receive updates from a WSUS server over unencrypted HTTP. The machine should be configured to proxy through the machine running this script. This can be done by manually changing the proxy settings or via other means such as WPAD poisoning (e.g. using Responder)

python wsuspect_proxy.py payload_name [port]

An example payload for PsExec is set up that will launch cmd.exe running as Administrator:

python wsuspect_proxy.py psexec

If you are having problems getting the script to work we'd recommend using a GUI proxy tool such as Burp (and configuring Burp to use this script as a proxy) to see if the update XML is being correctly inserted.

Customisation

Modify payloads/payloads.ini to change the payloads and their arguments.

Known Issues

• Currently doesn't support Windows 10 targets
• Doesn't yet support Python 3

Screenshots