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Reverse engineering a mysterious UDP stream in my hotel (2016)

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Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#81

Post by password11 »

gambiting wrote: post #58
paisawalla wrote: post #51

Earlier quoted context omitted.

> Would you protect against someone running down the corridor shouting the same thing? ...yes? Do you think hotels aren't protected, to some extent, against any random person putting on a blazer and announcing an emergency?

>>Do you think hotels aren't protected, to some extent How are they protected against that, exactly? You can literally walk up to any fire emergency button on any wall on any floor, press a button and evacuate the entire hotel, why bother with this UDP streaming nonsense?

> How are they protected against that, exactly? You can literally walk up to any fire emergency button on any wall

Cameras near fire alarms and it's a crime in the U.S. to give a false alarm.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#82

Post by anyfoo »

joshvm wrote: post #79
mike_d wrote: post #77

Earlier quoted context omitted.

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.

Does network latency dominate over speed of sound? Propagation time is about 3ms / metre in open air.

It basically does not matter if you sync your clocks via NTP and play back accordingly.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#83

Post by [deleted] »

petertodd wrote: post #39
gambiting wrote: post #30

Earlier quoted context omitted.

....why? No, honestly, why? Would you protect against someone running down the corridor shouting the same thing?

It's a lot more official if it's coming from the elevator speakers. It's also a lot harder to track down who did it.

[deleted]

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#84

Post by 867-5309 »

kibwen wrote: post #27

> But what was this audio? Was this a sneakily placed bug that listened to me? [...] I can’t believe I spent time for this. It’s just elevator music. Joke's on you, it's a bug listening to you in your room while using steganography to merely appear to be elevator music!

came here to say the same! but then the multicast would make less sense.. unless that was a complementary red herring

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#86

Post by dagurp »

matzf wrote: post #41
boucher wrote: post #38

Earlier quoted context omitted.

I'm not sure if the habit is because of the show or not, but I wanted to note for anyone who might be reading that "Detectorists" is a really charming British show that I highly recommend.

Yes, it was supposed to be a reference to the show, glad you picked up on it.

Pub?

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#87

Post by gambiting »

password11 wrote: post #81
gambiting wrote: post #58

Earlier quoted context omitted.

>>Do you think hotels aren't protected, to some extent How are they protected against that, exactly? You can literally walk up to any fire emergency button on any wall on any floor, press a button and evacuate the entire hotel, why bother with this UDP streaming nonsense?

> How are they protected against that, exactly? You can literally walk up to any fire emergency button on any wall Cameras near fire alarms and it's a crime in the U.S. to give a false alarm.

Right, that protects the hotel from liability, but it does nothing to protect the hotel from such false alarm happening in the first place.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#88

Post by password11 »

gambiting wrote: post #87
password11 wrote: post #81

Earlier quoted context omitted.

> How are they protected against that, exactly? You can literally walk up to any fire emergency button on any wall Cameras near fire alarms and it's a crime in the U.S. to give a false alarm.

Right, that protects the hotel from liability, but it does nothing to protect the hotel from such false alarm happening in the first place.

The threat to the perpetrator -- of 90 days prison time and a permanent criminal record of being a mischief-maker -- prevents people from pulling the alarm.

Same way sheepdogs herd sheep.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#89

Post by inferiorhuman »

kkielhofner wrote: post #75
ww520 wrote: post #66

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.

I worked on a WiFi multicast video streaming solution and while it theoretically works as well and is as easy as you describe in practice it can be a complete nightmare. 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, e…

Sonic used to offer mbone connectivity (including BBC channels) back when they were an internet service provider and not a web provider. It was pretty nifty but never very user friendly to set up.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#90

Post by koolba »

unwind wrote: post #68
blueberrychpstx wrote: post #67

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…

Even better than a canned audio file would be machine generated music. Otherwise you could detect that the “same” song is being transmitted with slightly different bits.

Or you could have an extremely long audio file so the repeat situation doesn’t occur.

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