Dec 09

ISACA Review: Hacking Exposed Wireless 2nd Edition

Hacking Exposed Wireless 2nd Edition CoverA special thanks to Horst Karin for posting a great review of my new book, Hacking Exposed Wireless 2nd Edition on the ISACA website.

If you haven’t already checked it out, you can browse the book through Amazon’s Page Viewer. For the first time in print, we provided an in-depth coverage of attacking and exploiting WiFi as well as ZigBee, Bluetooth and DECT technology in the approachable and understandable Hacking Exposed style.

Be sure to check out our companion website to grab the online content and associated files for download.

-Josh

Oct 25

Exploiting ZigBee at ToorCon 11 Slides

Yesterday I presented my findings on the security implications of the ZigBee protocol at ToorCon 11. I had a great audience and the presentation went smoothly where we looked at the basis of ZigBee technology and why ZigBee is important for embedded developers and interesting to attackers.

I also introduced a new project I’ve been working on dubbed KillerBee. KillerBee is a Python-based framework with several tools designed to exploit deficiencies in the design and implementation of ZigBee and IEEE 802.15.4 networks. The hardware I’m using with KillerBee is the AVR RZUSB stick, available from electronics resellers such as DigiKey and Mouser for $40/USD.

I’m still working on KillerBee, and it’s not quite ready for prime time yet. I’m planning on doing a full release at ShmooCon, so if you are interested in doing some hands-on ZigBee hacking at Shmoo, pick up a few RZUSB sticks and come find me at the InGuardians booth. I had a bunch of CD’s printed up and distributed at ToorCon for an early preview of KillerBee, sample packet captures, specification documentation and more. If you want to get a copy of that, please drop me a note.

In the meantime, you can grab my slides from the presentation. I’d love to hear feedback on ZigBee and what people are doing with this technology, so drop me a note and let’s chat.

-Josh

Oct 21

ToorCon 11: KillerBee – Practical Zigbee Exploitation Framework

On Saturday at ToorCon 11 I’m presenting my work in designing a framework and tools to exploit and manipulate ZigBee and IEEE 802.15.4 networks. KillerBee has been about 9 months in development, written in Python, leveraging the AVR RZUSB Stick as the interface to interact with these low-power networks.

ZigBee is a interesting wireless technology, not due to any particularly innovative design mechanisms (and certainly not from a robust security perspective) but because it interfaces with the kinetic world more than any other wireless protocol I’ve run into. It would be unheard of to use WiFi as a mechanism to control gas valves in distribution mains, and you would never see Bluetooth controlling a flood release main, yet ZigBee and IEEE 802.15.4 seem to fit in with these scenarios, often with little in the way of mature security testing.

My hope is that people evaluating ZigBee and IEEE 802.15.4 technology will be able to leverage KillerBee as a platform to test third-party products (and, for vendors, to test their own products) for vulnerabilities. In my presentation on Saturday, I’ll detail several examples of how I’ve been using KillerBee for this purpose, and how you can as well.

After the conference I’ll post my slides here, so stay tuned. If you are coming to ToorCon, please be sure to stop by and say “Hi”.

-Josh

Jul 28

Special Evening Webcast on Kismet Newcore Thursday!

On Thursday night at 7pm EDT (4pm PDT) I’ll be giving a special evening webcast called “Budget Wireless Assessment using Kismet-Newcore“. I delivered this content at the SANS Denver conference a few weeks ago, but several people have contacted me complaining that they wanted to get in on the new features Kismet has to offer including plugins, new security framework, the new user interface, integrated graph views and more.

For example, did you know that Kismet Newcore has the ability to apply fine-grained channel hopping controls, allowing you to easily configure Kismet to spend more time on commonly used channels (such as channels 1, 6 and 11)? This allows you to focus the data collection process while not missing any AP’s that might on uncommon channels.

Kismet Newcore Channel Configuation

Kismet Newcore Channel Configuation

The webcast will use the SANS vLive! (formerly @Home) setup based on Elluminate. This software gives me the ability to do live demonstrations during the webcast with a Q+A interface and the ability for viewers to ask questions during the session.

What’s more, attendees will get a 10% discount code off my upcoming Ethical Hacking Wireless course, delivered in manageable 3-hour chunks once a week for 12 weeks, starting September 7th. More information on the Ethical Hacking Wireless vLive! course is available at http://www.sans.org/athome/details.php?nid=19608.

Sign up for the webcast today! https://www.sans.org/webcasts/show.php?webcastid=92713

-Josh

Jul 11

Wireless Privacy Loss++; Amazon Kindle

Kindle DX

Kindle DX

Fellow hacker and all-around rock-star Sherri Davidoff and I have been chatting lately about a new form of privacy loss from Amazon in the form of the Kindle.

I’m a big Kindle user, and I love having a good deal of my tech library with me on the Kindle DX when I travel. When I’m on-site with a customer and want to reference something from the Database Hacker’s Handbook, for example, I can buy and download it in a minute. The alternative is to find a Border’s, drive there, buy the book, drive somewhere else because the first store didn’t have it, drive back to the customer and waste precious on-site engagement time. With the ability to read full 8.5×11 PDF’s as well (the ZigBee-2007 PDF is keeping me busy at the moment), it’s well worth the cost of the unit.

However, it turns out that the Kindle keeps track of what you read. Presumably, this is just for synchronizing your last-read page across e-readers, but I suspect a company that recognizes the value of customer information such as Amazon wouldn’t let this be the only thing they collect about their e-book users.

Check out Sherri’s post on this topic on philosecurity.com.

Privacy loss often comes in convenient forms; TiVO cataloging each second of TV you watch and skip, the Nike+iPod leaving a RF breadcrumb trail for where you go and who you associate with and many other examples. If anyone knows what Amazon’s policy is on the information they collect about Kindle users, I’d love to hear it.

Also check out my presentation from SANS 2009 titled “Privacy Loss in a Pervasive Wireless World.”

-Josh

May 11

Locating ZigBee Devices

ZigBee Device Finder

ZigBee Device Finder

Since the introduction of the ZigBee-2004 specification, the ZigBee Alliance has made significant improvements in the security of sensor-based wireless networks. Despite improvements introduced in later amendments including the ZigBee-Pro specification, the security is not bullet-proof, due to the significant constraints of CPU, flash and memory availability in low-cost devices. Designing around these constraints, the ZigBee Alliance has made reasonable security options available to vendors of ZigBee products, broadly classifying security levels into high-security mode (intended for enterprise applications) and low-security mode (intended for residential applications). Looking at the available offerings for ZigBee stacks from vendors such as Atmel, Microchip and TI, it is apparent that high-security mode costs more, not necessarily in software costs but in terms of memory, flash and CPU requirements.

If you read up on ZigBee, you’ll quickly identify the Achilles’ heel plaguing the security of any low-cost wireless technology:

“… due to the low-cost nature of ad hoc network devices, one cannot generally assume the availability of tamper resistant hardware. Hence, physical access to a device may yield access to secret keying material and other privileged information, as well as access to the security software and hardware.”
ZigBee Specification 053474r17, Jan. 2008; available from www.zigbee.org
ZigBee CC2420

ZigBee CC2420

Effectively, if you use sensor-based networks, and an adversary is able to steal a device, they can extract key information from the hardware which can be used to exploit the rest of the network. This style of attack has been demonstrated by my neighborly colleague Travis Goodspeed on multiple occasions, snagging encryption keys, dumping device firmware and many other interesting hacks with hardware in hand.

Following Travis’ article, a few people submitted posts indicating that while his attack is interesting, it requires hardware to be effective. Today, we’re a little bit closer to making that reality.
.

Introducing zbfind – ZigBee Location Tracking

Following my previous work on reversing the Microchip Zena ZigBee sniffer, I put together a quick Linux tool to passively sniff for the presence of ZigBee/802.15.4 devices and display some summary information about the identified devices. When a device is selected in the GTK UI, a speedometer needle and histogram will record the relative signal strength of the selected device with a relative distance estimate in feet using the free-space path loss formula. A screen-shot is displayed at the top of this post.

Readers from my SANS Ethical Hacking Wireless course will recognize this UI; it’s based on a tool Mike Kershaw and I wrote for Bluetooth analysis (that has yet to be released, but we have big plans for it, stay tuned). This initial code is a little rough around the edges, but provides a simple interface to track down and identify ZigBee and other 802.15.4 devices in the area.

I’m holding off on releasing this tool until I iron out a few more bugs, but am happy to share the code individually if folks 1. have a Microchip Zena Sniffer and 2. have experience with Linux and Python. Drop me a note if you are interested and meet these conditions (I don’t mean to be unfair, but I want to spend my time working on the code to add features and fix bugs instead of helping users, at the moment; thanks for understanding).

My Goals

My goal in releasing this tool is simple: provide administrators with the firepower to justify the added cost of enterprise-security ZigBee technology with hardware tamper-proof security features. If the tools don’t exist publicly, many people disregard the threat. By making this tool available, I’m hoping people will be able to use it as an argument to justify more expensive ZigBee hardware deployments where warranted by security policy.

-Josh

May 10

Reversing the Microchip Zena ZigBee Sniffer

Microchip Zena Network Analyzer

Microchip Zena Network Analyzer

A few days ago I bought a Microchip Zena ZigBee sniffer. This USB HID device comes with simple software for Windows that captures and decodes 2.4 GHz 802.15.4, ZigBee, MiWi (Microchip stack) and MiWi-P2P traffic. It’s $150, which is a little steep considering that it is a PIC18LF with USB and a MRF24J40 radio, but I’ve had fun playing with it all the same.

The Zena 3.0 sniffer software provides a basic per-packet view of frames. I guess we are all spoiled by Wireshark, but I was hoping for more detail and a better UI. The Zena sniffer can save a capture in a proprietary file format, and can export selected frames (to the clipboard) in space-delimited hex bytes.

A cool accompanying feature is the network configuration display interface where Zena will identify all the parent/child relationships observed. You can specify a BMP background as a floorplan and move the nodes to their physical locations as well.

Zena Packet Capture Tool

Zena Packet Capture Tool

Zena Sniffer Network Configuration Display

Zena Sniffer Network Configuration Display

SnoopyPro Capture of Zena USB Traffic

SnoopyPro Capture of Zena USB Traffic

With no Linux support, I decided to write my own user space Linux driver to capture packets with the goal of integrating it into libpcap captures and other tools including Kismet Newcore. Plugging into a Linux box, it was clear that the device was using the USB HID, which was good news for me since it would be simpler to reverse the configuration details. Using the SnoopyPro USB sniffer, I was able to look at the USB packets, observing data from frames shown by the sniffer, as well as recording the configuration activity based on the channel I specified to capture on.

With this information, it was straightforward to identify the USB endpoint 0×01 as the control channel (for setting the channel) and USB endpoint 0×81 as the data endpoint (for delivering frames). Using PyUSB with the excellent Pymissle project by Scott Weston as an example, I quickly put together a tool that can set the channel number and capture frames from the Zena device, dumping the hex bytes to stdout.

Linux Microchip Zena data, isn't it beautiful?

Linux Microchip Zena data, isn't it beautiful?

The Python script is available here. It’s hack, but it was enough to get me started on what will be my next post: zbfind, a location tracking and identification tool for ZigBee and 802.15.4 networks.

-Josh