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Does that mean someone can hijack the stream and play some end of world audios?
Sounds possible, but you’ll have to deal with address contention. Play some good old Rammstein, to make your elevator journey more pleasant.
" There was obviously data in this packet and file should know when it sees MPEG Audio data, so I decided to write another Python script to save the packet data with offsets. This way it would save the file test1 skipping 1 byte from the packet, test2 skipping 2 bytes and so on. Here’s the code I used and the result." Wouldn't binwalk do just that?
Earlier quoted context omitted.
okay this is way over my head - but this would have to be steganography hiding in the audio file that could only be run by someone like OP, detecting; downloading; etc the udp data, right?
Today (but perhaps slightly less in 2016, not sure) you could easily imagine a microcontroller (or FPGA) with a microphone that bugs you, but encodes that audio (using steganography) onto a canned audio file of elevator music, and then sends the result over the network "in the open". To a casual observer snooping the relevant network, it would probably (as here) look as elevator music, but to the intended recipient w…
Not just decode, but also decrypt.
You'd probably want to encrypt not just for the secrecy, but so that the noise introduced by the steganography doesn't seem so suspicious.
So either the elevator is on the same network, or they misconfigured the broadcast to all networks instead of the one needed. First one being much worse as it shows a failure to understand network segregation.
Actually the multicast audio is a pretty good system. There're multiple elevators. Broadcasting makes it simple to sync up the music on them. Using a Wifi speaker has much lower cost than adding a wired speaker to a moving elevator. It’s also simple and low cost to add extra WiFi speakers in other areas of the hotel, creating an ad hoc PA system.
Full disclosure this was a few years ago so things may have improved. I also can’t remember all of the specifics but there was a lot of low-level driver work, firmware tweaks, specific configurations of just about every WiFi param you can think of, etc.
So either the elevator is on the same network, or they misconfigured the broadcast to all networks instead of the one needed. First one being much worse as it shows a failure to understand network segregation.
> shows a failure to understand network segregation Why? It's highly likely they just don't care. Which is fine. It's an elevator speaker.
Sure it's an elevator speaker and probably you can't do much (probably! 'simple' devices are packing ever more hardware).
But something is sending those packets. What's that? Can it be hacked? What else can that device/server see? Are there other devices sharing the network with customers?
Actually the multicast audio is a pretty good system. There're multiple elevators. Broadcasting makes it simple to sync up the music on them. Using a Wifi speaker has much lower cost than adding a wired speaker to a moving elevator. It’s also simple and low cost to add extra WiFi speakers in other areas of the hotel, creating an ad hoc PA system.
For example you wouldn't want a wifi speaker in an elevator using a repeater at the top of the shaft trying to match up to a hardwired speaker in a ground floor vestibule.
Actually the multicast audio is a pretty good system. There're multiple elevators. Broadcasting makes it simple to sync up the music on them. Using a Wifi speaker has much lower cost than adding a wired speaker to a moving elevator. It’s also simple and low cost to add extra WiFi speakers in other areas of the hotel, creating an ad hoc PA system.
Remember that networks introduce latency. It might be tiny but the human ear can detect speakers being _slightly_ off. For example you wouldn't want a wifi speaker in an elevator using a repeater at the top of the shaft trying to match up to a hardwired speaker in a ground floor vestibule.
Actually the multicast audio is a pretty good system. There're multiple elevators. Broadcasting makes it simple to sync up the music on them. Using a Wifi speaker has much lower cost than adding a wired speaker to a moving elevator. It’s also simple and low cost to add extra WiFi speakers in other areas of the hotel, creating an ad hoc PA system.
Remember that networks introduce latency. It might be tiny but the human ear can detect speakers being _slightly_ off. For example you wouldn't want a wifi speaker in an elevator using a repeater at the top of the shaft trying to match up to a hardwired speaker in a ground floor vestibule.
Actually the multicast audio is a pretty good system. There're multiple elevators. Broadcasting makes it simple to sync up the music on them. Using a Wifi speaker has much lower cost than adding a wired speaker to a moving elevator. It’s also simple and low cost to add extra WiFi speakers in other areas of the hotel, creating an ad hoc PA system.
Remember that networks introduce latency. It might be tiny but the human ear can detect speakers being _slightly_ off. For example you wouldn't want a wifi speaker in an elevator using a repeater at the top of the shaft trying to match up to a hardwired speaker in a ground floor vestibule.
And then you "just" have the same problems that you have with purely electrically connected, analogue speakers (which are effectively 100% in sync in terms of receiving the signal): Sound is relatively slow, and so the audio from a speaker that is far away will reach you later than the nearby speaker.
You can mitigate that by adding a precise delay to the far away speaker... but of course that does not work if you're standing on the other side. Nevertheless, as said, that problem is regardless of whether your speaker is network-connected or not.