If you’ve read any of my previous posts on the topic I’m trying to get OOK, FSK and potentially PPM (Differential Pulse Position Modulation) working in the Linux kernel with the HopeRF RFM12B adapter. This is mostly for ARM SBC/SoC type situations like the RaspberryPi or beaglebone.
The intention here is to allow you to easily intercept, and transmit consumer wireless signals on the 434/868 MHz bands. There are existing ways to do this. However they all appear to depend on the Jeenode or at least an atmega chip running JeeLib.
I want to remove the dependency on the atmega, and yet still exploit the RFM12B to provide OOK/FSK transmission. Right now I’m adapting the existing RFM12B-Linux module to allow sending and receiving OOK signals, I’m also adding in the code to interact with specific defined devices. So far my thoughts are that it shouldn’t be too hard to have drivers for multiple devices in the module.
I thought best to do a link dump of everything that is currently important to this endeavour;
After merging someone else’s OOK sending efforts. I’m not too sure that listening for OOK and FSK is really important. After all an SDR can happily listen across the frequencies and decode the signals.
I unfortunately get very little time to work on this, or other projects on this blog but try to keep it updated with my experiments from time to time. Once I have my Salus under control I plan to release the branch on github. Until then I get a little time here and there to experiment. My latest outcomes have been hampered by insufficient power to my Pi3. There have also been some issues with transmitting on the 868 band.
I managed to get around to playing with the Ennio wifi doorbell a little more, trying to figure out how all of it works. It seems I have to learn a few things about UDP, however with a quick and dirty tcpdump on my openwrt router (which I was hacking in other ways earlier) to an NFS share on my RAID I managed to collect a chunk of worthwhile data while my phone interacted with the camera.
As far as I can tell without capturing all of the data of all of the interactions it goes something like this:
- Phone sends a broadcast request of some kind and the doorbell responds with a packet with it’s name to the UDP port specified by the initial contact.
- The phone logs into the device using the username and password provided by doing by sending a hex encoded ASCII string, with some preamble bytes:
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Here are the results of taking apart the Ennio wifi doorbell. I haven’t had a chance to dump the memory from this device yet, but I received a request to take some photos of the internals. Here are those photos;
The SoC is a RaLink RT5350, the data sheet for the chip can be found here. I guess some of the pins on the wide connector are for programming the memory chip (JTAG). I just need to work out which ones.
I’m looking for memory dump options, at first I wanted to mount my NFS server onto the device and dump to a file there, however that won’t work due to NFS being missing from the device. The other option is to dump it to telnet using base64 encoding, then decode it on the other side… This would be less than ideal but still possible. I need to boot the device up again to figure out what to do next.
Setting up a cross compile toolchain to build new binaries might be the best option for getting what I need out of this thing. Although I doubt the source code for the IPCam will be available to me.
The most important thing for me to do is to disable the wifi hardware. Once disabled it’s safe to actually put the hardware on the wall outside. I will likely need to take it down at some point, if I intend to flash the memory. I still wouldn’t recommend buying an Ennio wifi doorbell, or any of the variations out there. The failure point is the OS which is a black box of obscurity over security. I would love to have the time to develop a better open-source OS to run on these things which would work on foscam, wansview and others too. Like OpenWRT but for IPCams.
I recently purchased a Ennio Wifi Doorbell in order to have a doorbell, and also have an outdoor front of house security camera. It seemed like pretty much the only option available.
The camera is fairly easy to set up in the way it was intended. Install an app from the app store, and pair it (with magic, or zeroconf/bonjour) with your phone.
When the button is pushed a push notification arrives on your phone, I’m not quite sure how this happens yet but I’ll dig further. The camera sends a photo with the push notification and also allows streaming of video from the camera.
As far as I can tell both of these things work over 3G as well as Wifi flawlessly with a horrifying app UI.
First things first, is it secure?
With this thing going on the front of my house I want to know if it’s possible to break into it or in some other way use it to break into my network.
The short answer, this device is about as secure as a wet paper bag with a block of gold in it. This, although a major downside from a consumer perspective, leaves many open opportunities for the hardware hacker. Continue reading →