get utterance audio file about alexa-proxy HOT 3 CLOSED

Hi Corey, thanks for reaching out.

No, this proxy will not solve your problem. This is because of the split of the communication between the Alexa device and the Amazon server on one side and the Amazon server and the skill on the other side. This proxy is placed between the latter communication points, intercepting the request from the Amazon server to the skill and vice versa. That request/response does not contain any audio data, just the resulting action / command / question in text that is directed at the skill.

The communication between the Alexa device and the Amazon server (containing the actual audio) is secured and fixed to only work with Amazon servers. I'm not sure how exactly, but I guess the Alexa device has a hardcoded URL to post to and Amazon certificates installed to identify the server. So tampering with that will be very hard to do. You can ask Pindrop how they did it but I suspect they have a deal with Amazon that enables them to test with a modified Alexa device.

Good luck & regards, Erik

from alexa-proxy.

Thank you for going out of your way and for providing me with a detailed and informative answer! If it is any interest to you, I've done more research on the topic and I think the way pindrop did it is through a hardware vulnerability.

Basically, you boot the alexa from an SD card which grants you root access. You can then copy over a script that streams the audio from the always-listening microphones to a 3rd party server. This only works with 1st generation, 1st iteration echo devices.

You can read about it here:

Alexa, are you listening? Mark Barnes, 1 August 2017
https://labs.mwrinfosecurity.com/blog/alexa-are-you-listening

Amazon Echo Hardware Root via eMMC Debug Pins by echohacking on github
https://github.com/echohacking/wiki/wiki/Echo

A Survey of Various MethodEnroll Voice s for Analyzing the Amazon Echo, The Citadel, The Military College of South Carolina
https://vanderpot.com/Clinton_Cook_Paper.pdf

from alexa-proxy.

Hi Corey, thanks for your reply. Very interesting to read about the hardware hack. That seems like a plausible way for Pindrop to do what they did. If you're a bit handy with that you could use it too if you have a vulnerable device. Either way, good luck with your demo!

from alexa-proxy.