Teensy Programming for Everyone

Nikhil Mittal

About Me

SamratAshok Twitter - @nikhil_mitt Blog – http://labofapenetrationtester.blogspot.com Creator of Kautilya Interested in Offensive Information Security, new

attack vectors and methodologies to pwn systems. Previous Talks

Clubhack’10, Hackfest’11, Clubhack’11, Black hat Abu Dhabi’11

Upcoming Talks Troopers’12, PHDays’12, Hack In Paris’12 Training at GrrCON’12

Agenda - Introduction

A typical Pen Test Scenario How we are doing it Need for new methods to break into

systems HID anyone?

Agenda - Workshop

Introduction to Teensy Basics of Arduino Development Environment (ADE) Installing and configuring ADE to use with Teensy Understanding the basics of programming using ADE Writing Hello World Basic usage and programming of Teensy Introduction to Kautilya Demonstration of Payloads in Kautilya Program and perform attacks on a Windows machine Program and perform advanced attacks on a Windows

machine Understanding structure of and automation using

Kautilya Understanding Integration of payloads in Kautilya

Agenda - Conclusion

Protection against HID based attacks Pen Test Stories Limitations Future Conclusion

Let’s get started

Be as interactive as you can. Query me, ask nasty questions, insult me.

It is mandatory to laugh on jokes, they be on slides or cracked by me.

We will start slow and then pick up speed. Be patient if you know something, everybody is not good as you.

I don’t have much theory so be ready to see demos and source code.

Make sure you keep your eyes on. You should be able to program your device after this. I will keep checking if everyone is awake ;)

A client engagement comes with IP addresses.

We need to complete the assignment in very restrictive time frame.

Pressure is on us to deliver a “good” report with some high severity findings. (That “High” return inside a red colored box)

A typical Pen Test Scenario

How the threats are Tested

Vuln Scan Exploit Report

This is a best case scenario. Only lucky ones find that. Generally legacy Enterprise

Applications or Business Critical applications are not upgraded and are the first targets.

There is almost no fun doing it that way.

Some of us do it better

Enum Scan Exploit Report

Some of us do it even better

Enum +

IntelScan Exploit Post Exp Report

Why do we need to exploit?

To gain access to the systems. This shows the real threat to clients

that we can actually make an impact on their business. No more “so-what”

We can create reports with “High” Severity findings which bring $$$

What do we exploit?

Memory Corruption bugs. Server side Client Side

Mis-configurations Open file shares. Sticky slips. Man In The Middle (many types) Unsecured Dumpsters Humans <Audience>

Worse Scenario

Many times we get some vulnerabilities but can’t exploit. No public exploits available. Not allowed on the system. Countermeasure blocking it. Exploit completed but no session was

generated :P

Worst Scenario

Hardened Systems Patches in place Countermeasures blocking scans and

exploits Security incident monitoring and

blocking No network access

We need alternatives.

Best Alternative

Rajnikant > Chuck Norris

Need for new methods to break into systems

Bad guys are getting smarter. Smart attacks of 2011

Sony (ok not so smart :P) RSA (clever attack), chained to Lockheed Martin Epsilon (Spear Phishing) Barracuda Networks (WAF turned off for little while) Some attacks on India

Smart attacks of 2010 Stuxnet Operation Aurora

And Many more (like Apache in 2009)

Need for new methods to break into systems

Breaking into systems is not as easy as done in the movies.

Those defending the systems have become smarter (at many places :P) and it is getting harder to break into “secured” environments.

Everyone is breaking into systems using the older ways, you need new ways to do it better.

HID anyone?

Wikipedia – “A human interface device or HID is a type of computer device that interacts directly with, and most often takes input from, humans and may deliver output to humans.”

Mice, Keyboards and Joysticks are most common HID.

What could go wrong?

Introduction to Teensy

A USB Micro-controller device. Storage of about 130 KB. We will use Teensy ++ which is an

updated version of Teensy.

From pjrc.com

Current usage of Teensy

http://www.pjrc.com/teensy/projects.html

Really cool projects.

Arduino - Installation

Install Arduino Windows Serial Installer (only

Windows) Install Teensyduino Copy Teensy loader executable in

Arduino directory. Detailed with screenshots here:http://www.pjrc.com/teensy/td_download.html

Arduino - Configuration

Make sure to select correct “Board” and “USB Type” under Tools menu item.

If Teensyduino has been installed properly, sketch examples could be found at File->Examples->Teensy

Programming using ADE

Almost C++ like syntax is used in ADE

Two functions are required at minimum setup() which runs whenever Teensy is

plugged or restarted. loop() which keeps running after setup()

Basic usage and programming of Teensy

Writing Hello World with Teensy.

DEMO, Source Code and Programming

Kautilya

It’s a toolkit which aims to make Teensy more useful in Penetration Tests.

Named after Chanakya a.k.a. Kautilya. Written in Ruby. It’s a menu drive program which let

users select and customize payloads. Aims to make Teensy part of every

Penetration tester’s tool chest.

Payloads

Payloads are written for teensy without SD Card.

Pastebin is extensively used. Both for uploads and downloads.

Payloads are commands, powershell scripts or combination of both.

Payload execution of course depends on privilege of user logged in when Teensy is plugged in.

Payloads are mostly for Windows as the victim of choice generally is a Windows machine.

Windows User Add

Adds a user with Administrative privileges on the victim.

Uses net user command.

Default DNS

Changes the default DNS for a connection.

Utilizes the netsh command.

Edit Hosts File

Edit hosts file to resolve a domain locally.

Enable RDP

Enables RDP on victim machine. Starts the service. Adds exception to Windows firewall. Adds a user to Administrators group.

Enable Telnet

Installs Telnet on victim machine. Starts the service. Adds exception to Windows firewall. Adds a user to Administrators group

and Telnetclients group..

Forceful Browsing

Starts an invisible instance of Internet Explorer which browses to the given URL.

Download and Execute

Downloads an exe in text format from pastebin, converts it back to exe and executes it.

Sethc and Utilman backdoor

Using registry hacks, calls user defined executable or command when Shift is pressed 5 times or Win + U is pressed.

When the system is locked, the called exe is executed in System context.

Uninstall Application

Uninstalls an msiexec application silently.

Chrome RDP

This payload uses opens up chrome, launches Remote Desktop plugin, enters credentials and copies the access key to pastebin.

This payload operates on browser window.

Information Gather

Dumps valuable information from registry, net command and hosts file.

Sniffer

This payload pulls the sniffer powershell script (by Robbie Fost) and executes it on the victim.

The output is compressed and uploaded to ftp.

The Pwnage Saga Continues

Hashdump

This payload pulls powerdump script of msf from pastebin, schedules it as taks to run in system context and upload the hashes to pastebin.

Keylogging

This payload logs keys and pastes it to pastebin every twenty seconds.

There is a separate script to parse the output.

Wireless Rogue AP

This payload creates a hosted network with user define SSID and key.

It also adds a user to Administrators and TelnetClients group.

It installs and starts telnet and adds it to windows firewall exception.

Forced Wireless Connection

This payload forces the victim to connect to an attacker controlled WiFi AP. The AP in this case is portable WiFi hotspot on a smartphone.

Using this either payloads can be pulled from the smartphone or the internet using the AP thus effectively bypassing any internet restriction policies on the system.

Code Execution

This payload uses the powershell code execution script (by Matt from exploit-monday blog).

A meterpreter shell is executed completely in memory using this script.

Java Signed Applet Code Exec

This payload browses in background to a url where Metasploit Java Signed Applet module is hosted and accepts the run prompt after few seconds.

Pen Test StoriesLibrary Fun

We were doing internal PT for a large media house.

The access to network was quite restrictive.

The desktops at Library were left unattended many times.

Teensy was plugged into one system with a sethc and utilman backdoor.

Later in the evening the system was accessed and pwnage ensued.

Pen Test StoriesBreaking the perimeter

A telecom company. We had to do perimeter check for

the firm. The Wireless rogue AP payload was

used and teensy was sold to the clients employees during lunch hours.

Within couple of hours, we got a wireless network with a administrative user and telnet ready.

Pen Test StoriesHelp by the Helpdesk

A pharma company. We replaced a user’s data card with a

Teensy inside the data card’s cover. The payload selected was Keylogger. “Data card” obviously didn’t worked and

we got multiple keylogging for the user and the helpdesk.

Helpdesk guys had access to almost everything in the environment and over a workday, it was over.

Defense from malicious HID

Use Endpoint Protector 4 :P :P Group Policy in Windows which

prevent installation of hardware devices.

Limitations with Teensy

Limited storage in Teensy. Resolved if you attach a SD card with Teensy.

Inability to “read” from the system. You have to assume the responses of victim OS and there is only one way traffic.

Limitations with Kautilya

Many payloads need Administrative privilege.

Lots of traffic to and from pastebin. Inability to clear itself after a single

run. Not very stable as it is still a new

tool and has not gone through user tests.

For payloads which use executables you manually need to convert and paste them to pastebin.

Future

Improvement in current payloads. Implementation of SD card. Use some payloads as libraries so

that they can be reused. Support for Non-English keyboards. Maybe more Linux payloads. Implementation of some new

payloads which are under development.

Thank You

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