Hacker News Reader

Comment by 88e282102ae2e5b | Hacker News Reader

I guess we're beyond even considering that having an internet-connected smoke detector isn't necessary or desirable.

Or that automatic software updates are a security problem. "Software will eat the world," and every device around you will be controlled by software downloaded from somewhere on the internet.

They're the least bad alternative. Without automatic software updates, you instead have permanently-vulnerable devices (like most old home routers are today—they can be updated, but it's a manual process so users don't bother.)

I think they're a wash. Without them, you don't get patches unless you explicitly check for them. With them, you might not get patches anyways (like many Android phones), and are forever vulnerable to server-side breaches, or the manufacturer going out of business. Worst of all, an attacker only has to compromise the update server to compromise every associated device, rather than having to hack said devices one at a time.

No software updates mean your device is vulnerable to e.g. Heartbleed forever.

I like the idea that it can send me a message if I'm away from home. And it's not particularly easy for me to reach up to the ceiling to shut it down - much simpler to remote control it from my phone.

That said, the Nest really isn't that great!

You want something safety-critical to have as few parts as possible to keep one from affecting the other. That would be a nice feature. Best way to do it safely would be two devices: smoke detector with tiny component that sends RF waves whenever speaker sends sound; separate device w/ a radio and WiFi/Ethernet to notify you once detected. Means smoke detector can stay dumb and safe.

or just have a standard smoke detector, and an external sensor that waits for the sound the smoke detector makes.

This seems like the right approach--airgapped with redundancy. Not only is it more dependable and secure, it's also cheaper. You already have a smoke detector, so keep the parts that work.

That raises an interesting question: what other "dumb" devices can we connect to the internet safely through that same method?

Note that my RF method is extremely simple, dirt cheap, and has decades of field use. All kinds of industrial plants used that trick for local monitoring systems. Plus, it's strictly one-way transmission: can't hack it.

Devices on receiving end are simple enough to be made as secure (or not) as you'd like.

Anything that puts out simplistic PDUs, ideally one way only. A smoke alarm sends one one-way one-bit message, which can be done with a broadcast in any medium.

You could even achieve similar isolation even with an optoisolated RS-232 port if the protocol is auditable, non-general, and non-extensible. But good luck actually guaranteeing those things!

Internet access is akin to Turing completeness for programming languages - seemingly beneficial, easy to accidentally obtain, and ultimately a curse.

Your profile statement is interesting given Im going opposite route: from high-assurance security in software to learning hardware cuz software cant free us on subverted, inherently-insecure hardware. Gotta tweak tge hardware a la crash-safe.org or Cambridge's CHERI cpu to make job tractablw. Im still looking for EE's to run my tooling ideas and risk assessments by but those that help are uncommon. Send me an email if your interested in talking secure HW/SW architecture or methods.

Talk to the lowRISC folks?

That's on my TODO.

THAT is a good idea! Good out of the box thinking!

The only problem I see is that some kitchen appliances have high-pitched beeps that sound really similar. It would take some pattern recognition or something to ensure false alarms. I mean, "You're house is on fire!" is a more serious false alarm than most to get at an important meeting. ;)

This exists on the market now, but I can't remember the name.

just make sure it's off when the TV/streaming is running...

You mean like this one?

http://www.getroost.com/

A friend has one, and tells me that when his infant daughter screams, it sometimes notifies him that the house is on fire. I wonder if she's learned to game that system...

Reply on news.ycombinator.com