Senrio: JTAG explained

Senrio has a nice blog post on JTAG usage on consumer IoT devices:

JTAG Explained (finally!): Why “IoT”, Software Security Engineers, and Manufacturers Should Care: Imagine you are handed this device and asked to get root on it as quickly as possible. No further information is given. Where would you begin?  (If you just want to see the router get rooted, jump down to “Mounting an Attack: Rooting a Home Router” 😉 Our target: A VERY common/popular consumer Access Point. Since you have the device in your hands, you might try directly attacking the hardware. However, if you’ve never done any kind of hardware hacking, getting started can be intimidating. In this post, we are going to talk about the fundamental information you need to know to use JTAG for hacking hardware. We’ll also go over a quick example to illustrate the power of direct hardware access. […]



Hardware security at Security B-Sides Seattle

This month is B-Sides Seattle, and there are 3 hardware workshops (Attacking USB, JTAG, and Arduino) one by Joe (SecurelyFitz) and two by Matt (CryptoMonkey):


I think I heard Matt say this was the last time he was offering this  Attacking USB training…

Note that Joe also has training at CanSecWest and Black Hat, in addition to B-Sides Seattle..


Intel’s Debug Extensions for WinDbg

Windbg is Microsoft’s Windows system debugger (both user-mode and kernel-mode), which has the ability to load third party extensions. I just noticed some Windbg extensions that Intel has created. One enables Windbg to work over JTAG, the other enables support for Intel PT:


The “Intel Debug Extensions for WinDbg” consists of two sets of debugger extensions:

1) Intel Debug Extensions for WinDbg for IA JTAG debugging (IA JTAG) enables the connection of WinDbg to a target over the JTAG. The server acts as a mediator and forwards the calls from WindDbg* to the IPC interface and back.

2) Intel Debug Extensions for WinDbg for Intel Processor Trace (Intel PT) is designed to help WinDbg users by extending their debugging tool set with execution tracing. The extension allows for easy setup of Intel PT by abstracting hardware configuration and then reconstructing and displaying execution flow from the collected trace data. It will integrate with other WinDbg* features like symbolization and high-level source display.  Intel PT is a new technology for low-overhead execution tracing. It facilitates debugging a program by exposing an accurate and detailed trace of the program’s activity, and its triggering and filtering capabilities help identifying and isolating the relevant program executions. Intel PT records information about software execution on each hardware thread using dedicated hardware facilities. After execution completes, a software can process the recorded trace data and reconstruct the exact program flow.
BIOS / UEFI firmware: With firmware that is Intel PT-aware, you can set up an Intel PT-specific memory allocation. In this case, the firmware allocates a dedicated memory area and reserves it in a memory map for further use. Operating systems will recognize this reserved memory range and will not use it. When firmware reserves a memory region for Intel PT, it also configures the Intel PT output MSRs accordingly and indicates that Intel PT output configuration is ready to be used. The extension will recognize this setup. No further configuration (from user’s side) is required.

I presume these extensions are only available as part of the commercial-only Intel System Studio product. If you use Windbg, you may want to try to get these extensions, they sound useful.

More information:




Joe Fitzpatrick (@securelyfitz) has released the slides and samples for the recent 44Con talk on “JTAGsploitation”.

Quoting the *entire* 1-line readme here:

jtagsploitation: scripts and examples for using JTAG debug tools to gain root access

More information:


44con presentations available

44con just finished. I didn’t mention this event earlier, but it included a few interesting presentations and workshops:

Is there an EFI monster inside your apple?
Pedro Vilaça

Hands-on JTAG for fun and root shells
Joe FitzPatrick

Pen Test Partners IoT Workshop
Dave Lodge




Parallax announces JTAGulator:


Designed by Grand Idea Studio, JTAGulator is an open source hardware tool that assists in identifying OCD connections from test points, vias, or component pads on a target device.

The product is currently on sale for the next few days, 15% off until 2015-08-31 (US$136 instead of US$160).