Reverse Engineering a Furby

http://poppopret.org/2013/12/18/reverse-engineering-a-furby/

by Moral_ • 13 years ago

103 26 13 years ago

poppopret.org

mschuster914• 13 years ago

Are there maybe some JTAG lines exposed on the board?

Maybe these could be used for finding out the contents of the mem chip and the CPU used.

q3k• 13 years ago

This class of devices is often made at a ridiculously huge volume and the cheapest way possible, so they're very likely to contain one-time-programmable devices with no test / debug lines.

mschuster914• 13 years ago

Yet there are labeled(!) test points visible for the I2C lines on the board, and a number of other labels... so the question is, why doing the epoxy stuff while leaving the labeling on the PCB?

rhgraysonii• 13 years ago

It's projects like this that spark me to always go out and try to learn new things. I forget how much of our surrounded world is hackable sometimes, and it really is sad to think I get so caught up I don't think of these projects near as often as I used to. Hopefully this guy gets somewhere :) these writeups are inspiring, interesting, and educational all wrapped into one nice little package.

zdw• 13 years ago

It would probably be easier to read the chip in-situ with a Bus Pirate and flashrom :

http://dangerousprototypes.com/docs/Bus_Pirate

http://flashrom.org

I used one of these to reflash the BIOS on a logic board after the utility provided died, without removing the BIOS from the board.

tumes• 13 years ago

"A Furby is an evil robotic children’s toy wrapped in colored fur."

If only all technical reviews started this honestly...

shabble• 13 years ago

Whilst some impressive hacks (and especially convincing university staff to lend you their Expensive Toys), my understanding is that the really tricky bit is going from die scans to netlist/circuit diagram, and thence simulation/code extraction.

The Visual6502[1] folks are probably the best example of how well it can be done (assuming you can't afford to pay ChipWorks or FlyLogic to do it for you), but if you're working with a standardish MCU core and some masked ROM, a lower tech solution like the Dangerous Prototypes "rompar"[2] might work.

Probably requires quite a few dies, or plenty of experience in extracting them before you succeed though.

For actually reverse engineering the flash contents, I think it'd be easier to sniff the bus traffic as you probe it, or make a read/write capable emulator that logs what's going on. With the hacked phone-side control library, you could probably build a mostly automated harness to exercise the various settings and see what gets stored in flash.

[1] http://visual6502.org/

[2] http://adamsblog.aperturelabs.com/2013/01/fun-with-masked-ro...

userbinator• 13 years ago

Coincidentally it's very likely the new Furby also uses a GeneralPlus 6502 (CMOS) core.

glifchits• 13 years ago

Just funny to think that its possible that a dev who hacked on that Furby firmware is reading this and said "hey, I wrote that routine!"

agoandanon• 13 years ago

So, remember that virus that communicates using high-pitched sound? If no, here's an article:

http://arstechnica.com/security/2013/10/meet-badbios-the-mys...

This article says that the Furby communicates in the same way. It would be interesting if the Furby was a vector for spreading messages via this virus. Very, very interesting.

mschuster914• 13 years ago

I doubt this (Furbys are kiddy toys, after all); but this article proves that audio is indeed a viable data communication channel for bypassing air-gaps.

Juno5143• 13 years ago

lets ban audio

jrockway• 13 years ago

Someone should invent some sort of general modulator/demodulator and use sound to connect computers to the Internet!

drpancake• 13 years ago

From the Wikipedia article: "Furbies were banned from the National Security Agency of the United States due to concerns that they may be used to record and repeat classified information."

http://en.wikipedia.org/wiki/Furby

pbhjpbhj• 13 years ago

I've seen something along this line before - but this article is dated for Yesterday.

https://github.com/iafan/Hacksby found via hnsearch.com but I don't think that's where I saw the details last time.

There's this http://news.ycombinator.com/item?id=4984100 too - about open-source furby-like projects.

voltagex_• 13 years ago

I knew I remembered the GeneralPlus name from somewhere -

"Many Tamagotchis Were Harmed in the Making of This Presentation"

PDF: http://recon.cx/2013/slides/Recon2013-Natalie%20Silvanovich-...

Video (original? talk): https://www.youtube.com/watch?v=WOJfUcCOhJ0

Video (newer talk at ReCon): http://recon.cx/2013/video/Recon2013-Natalie%20Silvanovich-%...

Natalie Silvanovich did this kind of reversing on a few Tamagotchi products with great success.

Reverse Engineering a Furby

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