Cowpatty 4.5
After too much time I have posted coWPAtty 4.5 with several fixes and a couple of new features:
- Fewer restrictions on collecting the data needed to mount an attack. The default behavior requires all 4 frames of the 4-way handshake to mount an attack. If you specify "-2" on the command-line, coWPAtty will only require frames 1 and 2 of the 4-way handshake to mount an attack. More on this below.
- Validate that the needed information is present to mount an attack, without launching the attack (the "-c" option). This was requested by Pure Hate for an awesome project he gave me a preview on. I'm hoping details of this project will be public soon.
The "-2" option also includes fewer restrictions for validating the content of the packet capture. This was implemented by a patch submitted by Nathan Grennan, accommodating some AP's that do not strictly adhere to the IEEE 802.11i/IEEE 802.11-2007 specification.
Removing the restriction of needing all 4 frames of the 4-way handshake to mount an attack has some interesting implications. First, packet captures taken while channel hopping often miss parts of the 4-way handshake, since they can hop in the middle of the 4-way handshake exchange. Relying on only frames 1 and 2 gives you a better chance of catching the needed data even if you are channel hopping.
coWPAtty "-2" utilization example
Second, it provides the ability for an attacker to mount an attack against a client even if they aren't within range of their target network (for example, a WPA2-PSK user is at the airport).   Consider the following illustration:
Cowpatty Attack Scenarios
On the left is an example of what I consider a traditional WPA2-PSK attack. The attacker gets within physical proximity of the target network and waits for (or coerces) the 4-way handshake between an AP and a valid client system.
On the right, however, is a less-understood attack scenario. In the 4-way handshake, the client system authenticates first, sending a HMAC-MIC of frame 2 to the AP. If an attacker impersonates the legitimate SSID of the network, they are able to send Frame 1 of the 4-way handshake (no authentication) and observe the HMAC-MIC of frame 2. At frame 2, the attacker has everything they need to recover the PSK (now with cowpatty's "-2" option). Frame 3 fails validation by the client, but by that point, it's too late.
In practice, I'm testing this using HostAP running on my attack workstation, but that's not even necessary. Simply take any SOHO AP, configure the SSID to reflect that of your vistim with any pre-shared key and observe the exchange between the victim and the imposter AP, supplying the packet capture to coWPAtty with the "-2" option.
My transition to work for InGuardians has given me a chance to spend more time on penetration tests. As a result, I've started to change my mind about the value of "weaponized" attack tools. If the tool isn't reliable, works under many circumstances and flexible enough to withstand an error or two, it takes much longer to be useful, and that costs your customer more. I'm using this as a motivator to make tools more effective, capable of demonstrating a point, and thereby allowing you to providing greater value to your customer.
I'd love to hear comments and questions. Please add a comment below, or send me a note.
-Josh
June 4, 2009
Posted in: 802.11, Penetration Testing, Security, Tool 
One Comment
Kismet-Newcore Screenshots
Dragorn has posted a bunch of screenshots for Kismet-Newcore, demonstrating some of the cool UI features including traffic activity timeline view, update client list view, plugins view, network details view, color preferences, channel utilization (signal and noise) view, and channel configuration.
Kismet-Newcore Main UI View
Check them out at http://kismetwireless.net/screenshot.shtml.
-Josh
May 26, 2009
Posted in: 802.11, Security, Tool No Comments
Kismet Newcore RC1 Released
Just a little while ago, dragorn released RC1 of Kismet-Newcore, the much-awaited next-generation of Kismet. From the release news:
After 5+ years of development, this staging release is to work out any final minor issues before a full release. Kismet-2009-05-RC1 is expected to be fully functional, so please report problems on the forums or via email. Please read the new README and replace your configuration files, as just about everything about configuring Kismet has changed (for the better!) The old Kismet tree also sees a new release as Kismet-old-2009-05-R1, which incorporates minor fixes and support for some of the newer Intel and Ralink cards/driver names. Both are available from the download page.
Kismet-Newcore Screenshot
I've been moving away from using Kismet-Stable to the Kismet-Newcore architecture. On my short-list of awesome-new-features in newcore are:
- Plugin architecture makes it easy to add new functionality (passive and active) which promises to introduce significant new features on a more regular basis, not the least of which are support for DECT sniffing, live Aircrack-PTW WEP cracking and (coming soon?) ZigBee sniffing;
- Improved security model using suid-root group-exec-only interfaces;
- Lots of greater functionality in capture sources including improved channel hopping controls and graceful interface termination with dynamic interface adding (no more exiting Kismet to add or remove an interface from use);
- Save state feature where you can resume a previous capture state by running "kismet -r" on the runstate file;
- New menu-driver Kismet client interface which shows you the interesting information at a glance;
- Lots of new alerts and informational events help you in analyzing and assessing networks.
The development leading up to this release has been long in coming, and cheers to dragorn for continuing the introduce awesome new features that push the edge of what this powerful tool can do.
Take a look at the new Kismet-Newcore and enjoy this gem of the open source community.
-Josh
May 26, 2009
Posted in: 802.11, Security, Tool 4 Comments
Wlan2eth 1.2 Release
Wlan2eth is a tool I wrote to convert 802.11 packet captures into Ethernet-style captures; I find this useful when working with various sundry tools that don't properly handle 802.11 frames.
Adrian Crenshaw sent in a bug report for wlan2eth where he was getting the following output:
$ ./wlan2eth ../forjosh.pcap out.dump
Converted 0 packets.
Turns out I didn't have support for other 802.11 packet capture link types (Adrian was using PRISM_AVS). I've updated wlan2eth to fix this issue, while adding support for Ad-hoc network captures as well.
Thanks,
-Josh
May 13, 2009
Posted in: 802.11, Linux, Tool No Comments
Locating ZigBee Devices
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
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.
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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 11, 2009
Posted in: Linux, Security, ZigBee One Comment
Reversing the Microchip Zena ZigBee Sniffer
Microchip Zena Network Analyzer
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 Sniffer Network Configuration Display
SnoopyPro Capture of Zena USB Traffic
With this information, it was straightforward to identify the USB endpoint 0x01 as the control channel (for setting the channel) and USB endpoint 0x81 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?
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
May 10, 2009
Posted in: Hardware, Linux, Reverse Engineering, ZigBee 3 Comments
SANS Introduces “Fuzzing for Bug Discovery”
A few minutes ago I submitted what is hopefully the last set of edits for a new day of training material I wrote titled "Fuzzing for Bug Discovery". This hands-on day of material joins Steve Sims' Developing Exploits for Penetration Testers and Security Researchers course.
If you haven't already checked out Steve's course, I highly recommend it. In just a few days, he has been turning students into exploit developers, using hands-on labs to reinforce focused training materials. The new day of fuzzing material also gives students training on the tools and techniques for software fault testing using canned and custom fuzzing tools. A quick sampling of topics includes:
- Why fuzzing is needed for security, and how it can be used by Quality Assurance teams, software developers, vendors and penetration testers
- Building your attack plan, sources for data collection, testing and monitoring techniques and tools
- Fuzzing techniques including static test case development, randomized fuzzing, mutation and intelligent mutation fuzzing
- Fuzzing opportunities and common software developer mistakes to target
- Effective fuzzing through code coverage analysis using available source or closed binaries
- In-depth coverage on building custom fuzzers with Sulley
If I had to pick, I'd say the best part of the new day are the lab exercises. In the labs, you'll use a variety of tools including Taof, Gcov/Lcov, Paimei with Pstalker, IDA Pro with the idapython plugin, the Sulley fuzzing framework and a bunch more. In the labs, you'll definitely find interesting and useful bugs that, at the end of Steve's course, you'll be writing exploits for.
Steve is teaching his Developing Exploits for Penetration Testers and Security Researchers course in several upcoming conferences:
As always, I'm more than happy to any answer questions about this day of material. I'll also try to answer questions about the entire course, though I may defer you to Steve. In the meantime, check out the description and sample topics. Also, my thanks to Steve for the chance to contribute to his awesome course.
-Josh
May 10, 2009
Posted in: Exploit, Fuzzing, Hacking, Training No Comments
Follow the Bouncing Malware: Gone With the WINS
Tom Liston is a unique individual. Not only is he technically skilled in many areas, but he has the Kurt Vonnegut gift of being able to write a story that both delivers a message and keeps you entertained with simple sentences (oh, and teaches you a thing or two about malware analysis).
Follow the Bouncing Malware (FTBM) is a great series of articles Tom has published at the Incident Storm Center. Some are a little cheeky, but if you had met Tom you'd think they fit him perfectly. Be sure and check out the latest installment, Follow the Bouncing Malware: Gone With the WINS and pick up some tidbits on malware, Windows 2003 systems getting pwned and pr0n.
-Josh
May 7, 2009
Posted in: Exploit, Malware, Reverse Engineering, Security, Windows 2003 No Comments
Pen Test Perfect Storm Trilogy Slides
Over the last several months I had the pleasure of working with Ed Skoudis and Kevin Johnson in presenting a trilogy of webcasts titled the Pen Test Perfect Storm where we talk about techniques to combine network, web app and wireless pen testing. By combining these components of classic pen-tests, we are able to more effectively test the network for threats and dig deeper into an organization. Check out the slides and links to the webcast archives here:
Special thanks to Ed and Kevin for the chance to work with them on this series. Please drop me a note with any questions.
-Josh
May 3, 2009
Posted in: 802.11, Exploit, Hacking, Penetration Testing, Security, Vista No Comments
Why Zoher Anis Rocks My Inbox
If you haven't met Zoher Anis at a SANS conference or other popular venue, please make an effort to do so as soon as possible. Zoher is one of the most awesome guys I know, and humbles me with his new presentation "Why Joshua Wright loves Windows Vista ? And why you should be glad you’re not running it."
Zoher came up to me at the SANS 2009 Orlando conference and showed me a slide deck he made for a private audience about some of the awesome wireless stuff Microsoft added to Windows Vista. In it, he applies a lot of the Vista wireless hacks I wrote about in Vista Wireless Power Tools (for the penetration tester), and adds his own excellent Vista hacks in the process.
After I begged and pleaded, he allowed me to distribute a sanitized version on my site. For your enjoyment. Thanks Zoher!
-Josh
April 11, 2009
Posted in: 802.11, Hacking, Penetration Testing, Security, Vista, Wireless No Comments