Category: RESEARCH
Hacking Washington DC traffic control systems
This is a short blog post, because I’ve talked about this topic in the past. I want to let people know that I have the honor of presenting at DEF CON on Friday, August 8, 2014, at 1:00 PM. My presentation is entitled “Hacking US (and UK, Australia, France, Etc.) Traffic Control Systems”. I hope to see you all there. I’m sure you will like the presentation.
I am frustrated with Sensys Networks (vulnerable devices vendor) lack of cooperation, but I realize that I should be thankful. This has prompted me to further my research and try different things, like performing passive onsite tests on real deployments in cities like Seattle, New York, and Washington DC. I’m not so sure these cities are equally as thankful, since they have to deal with thousands of installed vulnerable devices, which are currently being used for critical traffic control.
The latest Sensys Networks numbers indicate that approximately 200,000 sensor devices are deployed worldwide. See http://www.trafficsystemsinc.com/newsletter/spring2014.html. Based on a unit cost of approximately $500, approximately $100,000,000 of vulnerable equipment is buried in roads around the world that anyone can hack. I’m also concerned about how much it will cost tax payers to fix and replace the equipment.
One way I confirmed that Sensys Networks devices were vulnerable was by traveling to Washington DC to observe a large deployment that I got to know.
When I exited the train station, the fun began.
A Wake-up Call for SATCOM Security
- Aerospace
- Maritime
- Military and governments
- Emergency services
- Industrial (oil rigs, gas, electricity)
- Media
Atmel AT90SC3232CS Smartcard Destruction
Having heard that Atmel actually produced three variants of the AT90SC3232 device, we did some digging and found some of this previously never-seen-by-Flylogic AT90SC3232CS. We had already several AT90SC3232 and AT90SC3232C. We assumed that the CS was just a 3232C with an extra IO pad. Well, one should never ass-u-me anything! The AT90SC3232CS is a completely new design based on the larger AT90SC6464C device.
Decapsulation revealed that Atmel actually did place an active shielding over the surface of the device. A 350nm, 4 metal process was used on the AT90SC3232CS where the AT90SC6464C was a 350nm, 3 metal.
A quick polishing session removes that residue you saw in the previous photo. Now the device looks very similar to the AT90SC6464C.
Given the AT90SC family all run encrypted code that even Atmel claims they don’t know the key on. It’s mandatory to polish down the device and image areas of interest at each level to trace through the logic.
With the chip at Metal 2, it was time to go to Metal 1. This is where the actual transistor is put together to become something such as AND, OR, INVert, …
While not really required but always desired, removal of Metal 1 leaves us with the poly/diffusion areas visible. This is always helpful to explain P/N FETs for our purposes.
Given the feedback received from the recent 3 Metal display, we thought we would do it again. This time however, we imaged it at 1000x for a distance of 25,000 pixels across by 2413 down (25,000 is the max a JPEG will allow).
Having no knowledge of how the Atmel AVR smart card family works means we have to tear it down and trace out the databus paths. Â The next 4 images are just a sample of the real image we created. Â The real image is so huge, it would take days to download.
The next four images can be clicked on to open up the full 25,000 pixel JPEG.  Metal 4 was not imaged because it was the active shield.  The active shield is an obstacle  that can be ignored until the signals determined to be important are identified.
This is definitely the memory encrypt-decrypt block (MED) or at least the entry of it ;).
Intel 4004
Before going deeper into the analysis of today’s chips, we will take a quick journey to where it all began: the Intel 4004, world’s first widely-used microprocessor. The 4004 and most other antiquated chips differ from modern chips in two main characteristics: They only use a single type of transistor (PMOS or NMOS) and each logic gate is custom-designed to best utilize the available area — an inevitable optimization for chips built from transistors about 150x larger than those used in their modern descendants.
Each of the gates is composed of two transistors and one resistor. If either of the transistors is open (that is: having Vcc applied to its gate), the output is strongly connected to Vcc. If neither of the transistors is open, the gate is weakly connected to GND through the resistor, but still strong enough to pull the output to GND.
PMOS is very area-efficient, but more power hungry and slower than alternatives such as CMOS, which combines PMOS and NMOS transistors as illustrated in this post. It’s beautiful to see how none of the inefficiencies we see in modern chips are found on the 4004 and how the available space is completely filled with logic.
As a challenge for next time, identify the extra 3 layers that the Intel museum claims. Last episode’s challenge was correctly solved first by Jeri Ellsworth. Respect for her almost perfect circuit diagram as well as her remarkable on-your-kitchen-table semiconductors fab.
Credit for the chips go to Tim McNerney. Tim is an expert on the 4004 who has built an interactive exhibit of the chip for the Intel museum. For more information please visit the Intel 4004 35th anniversary project web site.
-Karsten Nohl