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Abstract: Within the next few years, billions of IoT devices will densely populate our cities. In this paper we describe a new type of threat in which adjacent IoT devices will infect each other with a worm that will spread explosively over large areas in a kind of nuclear chain reaction, provided that the density of compatible IoT devices exceeds a certain critical mass. In particular, we developed and verified such an infection using the popular Philips Hue smart lamps as a platform. The worm spreads by jumping directly from one lamp to its neighbors, using only their built-in ZigBee wireless connectivity and their physical proximity. The attack can start by plugging in a single infected bulb anywhere in the city, and then catastrophically spread everywhere within minutes, enabling the attacker to turn all the city lights on or off, permanently brick them, or exploit them in a massive DDOS attack. To demonstrate the risks involved, we use results from percolation theory to estimate the critical mass of installed devices for a typical city such as Paris whose area is about 105 square kilometers: The chain reaction will fizzle if there are fewer than about 15,000 randomly located smart lights in the whole city, but will spread everywhere when the number exceeds this critical mass (which had almost certainly been surpassed already).
To make such an attack possible, we had to find a way to remotely yank already installed lamps from their current networks, and to perform over-the-air firmware updates. We overcame the first problem by discovering and exploiting a major bug in the implementation of the Touchlink part of the ZigBee Light Link protocol, which is supposed to stop such attempts with a proximity test. To solve the second problem, we developed a new version of a side channel attack to extract the global AES-CCM key (for each device type) that Philips uses to encrypt and authenticate new firmware. We used only readily available equipment costing a few hundred dollars, and managed to find this key without seeing any actual updates. This demonstrates once again how difficult it is to get security right even for a large company that uses standard cryptographic techniques to protect a major product.
A PDF of the paper is available here.
(Score: 2) by c0lo on Tuesday April 18 2017, @09:06PM (9 children)
Yes, the LED will last 20 years, provided it's properly cooled. Too bad the radiator the LED is mounted on (or the thermal contact grease) is planned to obsolesce in 1 year.
Like a tent of "UV-oblivious" fabric, sewn with a thread that dissolves at the first rain.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by VLM on Tuesday April 18 2017, @09:18PM (8 children)
I think thermal shock killed it as we're nowhere near peak summer temps. Just one too many temp cycles. Which is what kills most old fashioned bulbs too...
(Score: 0) by Anonymous Coward on Tuesday April 18 2017, @10:11PM (7 children)
Not only the above, but all except the best quality LEDs flicker. Something to do with rectifiers and the AC to DC conversion. You'd probably know more about it than me; I'm not an EE type. Check youtube for slow-motion videos of LEDs flickering.
I started buying CFLs the moment they became available, and I haven't looked back. I've been very satisfied. Somehow I've avoided all these CFLs that take minutes to warm up, must be by pure chance since I tend to buy whatever's cheapest with the color temperature and wattage I want.
(Also helps not to think in terms of "ok, this is a 100W replacement"--it's a 21W or 23W or w/e bulb. It pulls 21W/23W/w/e. And I have never met a CFL that's as bright as the incandescent it's supposed to replace. If I want to replace a 75W incandescent, I get a 100W replacement CFL. Marketing FAIL, but that's why people who can do and people who can't go into marketing.)
No experience with dimming bulbs here.
(Score: 2) by kaszz on Wednesday April 19 2017, @01:38AM
The problem with watt equivalence is that everyone has their own conversion factors and those are based on very specific cases of technology. So it ends up being a big mess. What you need to look for is *lumens*.
Adding to that comparison complication is the beam pattern and spectrum mismatching.
(Score: 1) by Scruffy Beard 2 on Wednesday April 19 2017, @01:39AM
CFLs die if you put them in an enclosed fixture: even if that fixture came included at the factory to hide that it was a CFL bulb.
LED circuitry has essentially the same temperature target (~40C). Enclosed fixtures are merely designed to keep the temperature below about 105 or 125C.
Even though the new lights use less power, the fixture is not able to cool as well at lower temperatures [wikipedia.org] (radiation is proportional to absolute temperature raised to the 4th power).
(Score: 0) by Anonymous Coward on Wednesday April 19 2017, @10:00AM
I can't stand flicker, thankfully not all LED bulbs do that. Even cheap ones can be okay, I bought some decent 1000+ lumen ones for 6,90€ the other day, but you can also pay >20€ a pop and still get flickering pieces of shit for your money. If they are on display and you can't tell if they flicker or not because of ambient lighting, you can use a phone camera to check. The rolling shutter effect will cause moving bright and dark stripes to show up as long as the exposure time is sufficiently short relative to the frequency of the flicker.
BTW incandescents and particularly halogen bulbs flicker too. Good CFLs and LEDs are much better.
(Score: 1) by WillR on Wednesday April 19 2017, @03:38PM (3 children)
Check youtube for slow-motion videos of LEDs flickering.
Or lawfully acquire (*cough*) any episode of Top Gear from about the last 5 years. All the high end cars they test drive have LED running lights, and most of them flicker quite clearly in the "sexy super slow-mo" shots.
(Score: 2) by kazzie on Thursday April 20 2017, @05:53AM (2 children)
I've seen such flashing LEDs on Top Gear, but why are they flashing? Car electrics run off a DC battery, so they don't need a built-in rectifier.
(Surely it's not caused by the rectified output of the alternator, I'd expect the battery to smooth out that ripple.)
(Score: 2, Insightful) by WillR on Thursday April 20 2017, @04:08PM (1 child)
(Score: 2) by kazzie on Thursday April 20 2017, @05:26PM
I think you've got it there. Here's a datasheet [ti.com] for a PWM-based driver for automotive daytime running lights and an aftermarket unit for sale online [amazon.co.uk].
It seems that the lights are dimmable for low intensity during the day, and full power at night.