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Laser-Based Audio Injection Attacks on Voice-Controllable Systems [pdf]
- sp332 7y agoThis is a cool attack, but I'm not sure where you got "$14" from. The laser pointers were $18 for a pack of 3, but you need a separate laser driver like the $300 one the authors used, and probably an audio amplifier as well. There are some videos of the attack at https://lightcommands.com/ https://lightcommands.com/
- ron0c 7y agoExactly. Title says "$14" and then show this as the setup: https://i.imgur.com/SYUSIDs.png https://i.imgur.com/SYUSIDs.png
- phailhaus 7y ago"Google Assistant can be hijacked by a $2 pack of screws!"
- deleted 7y ago[deleted]
- knowaveragejoe 7y agoIf you scroll further down, they show a significantly cheaper setup.
- dkonofalski 7y agoSo your typical Reddit/Hacker News new computer build. "$300 for the whole thing. (Note: This doesn't include the GPU, motherboard, case, or monitor that I already had prior to building.)"
- thsowers 7y agoAgree, title should be more like "Light Commands: Laser-Based Audio Injection Attacks on Voice-Controllable Systems"
- Someone1234 7y agoParticularly as this isn't exclusive to smart assistants. They found the same could be used against phones and tablets (as slightly higher power due to the lower sensitivity of the microphones).
- hanniabu 7y agoI foresee a market for decorative chotskies with open centers that sit over the mic to prevent these peripheral attacks.
- eeZah7Ux 7y agoModulating a laser at audio frequencies is pretty trivial. You can probably inject the signal straight from the headphone output of a smartphone into the right pad in the laser pointer with a decoupling resistor and inline capacitor. ...if you don't care about audio quality and longevity of the laser. http://www.yak.net/fqa/229.html http://www.yak.net/fqa/229.html
- kordlessagain 7y agoClickbait PDF
- thih9 7y agoTo be fair, the PDF's title is different, "Light Commands: Laser-Based Audio Injection Attacks on Voice-Controllable Systems". Maybe we should change this submission's title to the PDF's title.
- brudgers 7y agoStipulating that $14 might be off by as much as two orders of magnitude, cost remains an insignificant barrier for any adversary with access to a credit card.
- dang 7y agoWe changed the title from "Siri, Google Assistant, and Amazon Alexa can be hijacked with $14 laser pointer". Submitters: please don't editorialize like that. It breaks the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- exabrial 7y agoI don't understand why anyone wants these listening devices in their home
- travbrack 7y agoThere's already one in your pocket
- temp2206 7y agoAlso I believe it will move towards a voice free AI determined system. Because at some point in future decision making will be the toughest activity. (Currently moving and switching on buttons is)
- bduerst 7y agoYep, predictive decision making is the next steps. An example of this is on the newer versions of Android, where when you pull up the app tray, it predicts and shows which apps it thinks you're most likely to want to use based on datetime, location, connected peripherals, accelerometer (driving), etc. For the connected home it could be the same.
- sp332 7y agoThe ads make them look cool. Amazon puts them at the top of the site so it looks like they're popular and everyone wants one. The industrial design makes them super unobtrusive, and the cheerful voice comes off as ultra benign.
- lostgame 7y agoOkay, but they’re still the largest global privacy violation technology in history...you couldn’t pay me to have one of these in my home, and I mean; a lot - you could offer me cash every month to keep this in my house and I would still say no. These devices are as literally Big Brother as it gets. I personally boycott Google products and do not purchase from Amazon. Google has gone from ‘don’t be evil’ to ‘be evil and pretend we’re still cool’.
- fpgaminer 7y agoI don't know if the authors mention it, but it seems like you could combine this with the vishing attack (https://news.ycombinator.com/item?id=21306612 https://news.ycombinator.com/item?id=21306612) by using silent light commands to get a malicious app installed. Fun stuff...
- dantle 7y agoI'm a bit surprised that this works. It appears that this attack targets a single microphone. However, internal to most of these home assistant devices (e.g. Echo or HomePod) there is an array of microphones. A real sound from a spoken word would probably show up on more than one microphone (with an appropriate time and phase offset), although it seems to not be currently required. It seems like it would be complex or impossible for an attacker to target more than one microphone with this attack.
- MauranKilom 7y agoThis is covered in the paper. They acknowledge this defense technique while also pointing out that a laser flashlight could be used to illuminate all microphones at once.
- deleted 7y ago[deleted]
- penagwin 7y agoThe power output would need to be much higher and I'm not sure it'd work as well through glass, I'm thinking something more like multiple lasers?
- rmsaksida 7y agoWhat about internal microphones?
- dantle 7y agoPerhaps the "all at once" attack could work against today's hardware. This is because the mics (in devices I know of) are co-planar and the user may be speaking to Alexa (or whoever) from directly above or below the device. In this configuration, it is valid for all mics to be receiving the same audio signal simultaneously. But in some future rev, one could imagine that if the mics in the array are non-coplanar (e.g. at least 4 mics) and sufficiently far from each other, then there is no possible way for the audio signal to reach them at once (unless it is actually light being measured).
- smolsky 7y agoFor the ones too lazy to RTFA: VIII. CONCLUSIONS AND FUTURE WORK In this paper we presented LightCommands , which is an attack that uses light to inject commands into voice-controllable systems from large distances. To mount the attack, an attacker transmits light modulated with an audio signal, which is converted back to the original audio signal within a microphone. We demonstrated LightCommands on many commercially available voice-controllable systems that use Siri, Portal, Google Assistant, and Alexa, obtaining successful command injections at a maximum distance of more than 100 meters while penetrating clear glass windows. Next, we highlight deficiencies in the security of voice-controllable systems, which leads to additional compromises of third-party hardware such as locks and cars. Better understanding of the physics behind the attack will benefit both new attacks and countermeasures. In particular, we can possibly use the same principle to mount other acoustic injection attacks (e.g., on motion sensors) using light. In addition, heating by laser can also be an effective way of injecting false signals to sensors.
- blhack 7y agoMan this is such a great hack. This reminds me of the old TEMPEST attacks against CRT monitors from the 90s. Cool stuff!
- zbs7 7y agoThey made a simplified video explanation here: http://youtu.be/ORji7Tz5GiI http://youtu.be/ORji7Tz5GiI
- deleted 7y ago[deleted]
- wooptoo 7y agoAccording to their website the Google Home mini, the one with the cloth mesh top, is surprisingly one of the most resilient to this type of attack, being limited to about 20m in ideal conditions(1). It's also one of the cheapest voice controlled home assistant devices, being given away by Spotify, Google and others on special promotions. (1) https://lightcommands.com/ https://lightcommands.com/
- adamch 7y agoThis is cool research, but I hope people aren't viewing this as a real-world worry. By the time someone is breaking into my house to set up hundreds of dollars worth of laser equipment, I probably have bigger problems.
- CraneWorm 7y agoThey triggered the device from across the street.
- blakes 7y agoIf you'd actually read the paper, you can see that they were able to inject commands through double pane glass from 75 meters away.
- adamch 7y agoI know, but I have a fence around my house. Once someone is setting up equipment around my house, why not just smash a window and steal my stuff directly?
- adimitrov 7y agoFor this attack nobody needs to break into your home. It can be executed from a distance (100m) and through "clear glass windows."
- Upvoter33 7y agoand, the attack may be "open the front door / garage door" ...
- eeZah7Ux 7y agoThe hardware can be much cheaper. Furthermore, stealing very expensive cars would pay off the cost very quickly.
- stefan_ 7y agoHuh? I mean we have seen the WiFi person detection hacks through walls that need a lot of calibration, careful setup and so on, but this was pretty straightforward. Modulate your sound signal onto the laser current and it reproduced more or less directly.
- w-m 7y agoI really liked their take on the countermeasures: "It is possible to reduce the amount of light reaching the microphone’s diaphragm using a barrier that physically blocks straight light beams [...] However, we note that such physical barriers are only effective to a certain point, as an attacker can always increase the laser power in an attempt to compensate for the cover-induced attenuation. Finally, in case such compensation is not possible, the attacker can always use the laser to burn through barriers, creating his own light path." Sure, you can try to defend by putting a lid on the microphone. But we already have a laser here, we'll just burn through that.
- ilikepi 7y agoI wonder if simply having dirty windows would be a more effective countermeasure. See also "Real Genius".
- brianberns 7y agoIf someone is willing to blast your possessions to bits using a laser, I think the security of your smart devices is probably the least of your immediate concerns.
- Majromax 7y agoI don't see how that follows? A thief might be willing to break a conventional door lock if it gains them access to high-value, fenceable possessions. In this hypothetical, the hostile actor isn't interested in the smart speaker itself, they're interested in what the smart speaker can do.
- brianberns 7y agoMy point is that if someone is directing a powerful laser into your home, you are in imminent mortal danger, which is worse than whatever the smart speaker can do.
- virgil_disgr4ce 7y agoFor such a thorough and insightful paper, I wonder if they mean this as a joke. Not even a 1W laser is going to burn through any common, real-world materials at a distance.
- gruez 7y agoCan someone explain the mechanism that causes light to translate to electrical signals in the microphone? Is the heat generated moving the diaphragm? Is the microphone photosensitive?
- mav3rick 7y agoKind of related but light can change photo sensitive resistors, which can change current i.e. change electric signal.
- Scaevolus 7y agoIt's radiation pressure from the pulsed beam of light moving the tiny microphone. MEMS microphones are tiny capacitors that are vibrated by sounds. In section IV.C of the paper, they test whether the effect is mechanical or photoelectric, and determine that it's acting via mechanical vibrations, since the effect is stopped by gluing the microphone down with a transparent bit of glue. Think of it as a tiny solar sail-- they're hitting a very small piece of metal with a lot of photons, so even minor deflections are translated effectively. "The diaphragm is a thin membrane that flexes in response to an acoustic wave. The diaphragm and a fixed back plate work as a parallel-plate capacitor, whose capacitance changes as a consequence of the diaphragm’s mechanical deformations as it responds to alternating sound pressures. Finally, the ASIC die converts the capacitive change to a voltage signal on the output of the microphone." "As can be seen, the modification decreases the amplitude of the signal detected by the microphone, and the signal after the glue application is less than 10% of the original signal. We thus attribute our light-based signal injection results to mechanical movements of the microphone’s diaphragm, which are in turn translated to output voltage by the microphone’s internal circuitry."
- gpm 7y agoWhy did they need to focus the laser through a telephoto lens? I thought the whole point of lasers was that they were already focused into a beam that is moving in nearly exactly one direction?
- oceliker 7y agoLasers are collimated [0], not focused. They might be focusing it to maximize light intensity at the required spot. [0] https://en.wikipedia.org/wiki/Collimated_beam https://en.wikipedia.org/wiki/Collimated_beam
- ryanmercer 7y agoLasers spread just like a flash light with distance, the ones shined at the mirrors left on the moon by the Apollo missions for example were 6.5 kilometers wide by the time they reached the moon. Personally I've seen cheap lasers without a good focussing mechanism get house sized at even a few hundred yars, I bought a 1w laser diodes years ago that had no optics to focus it and at a foot it was roughly the size of a dime and absurdly bright and at a few hundred yards the diameter was taller than a door and incredibly dim -we tested it by shining it across a pond at the apartments we were living at one night aiming where there were no windows and immediately turned it off due to the massive size of the dot. I imagine they were just using what they had on hand to attempt to make a collimating lens/focusing Lens. If you have a pair of binoculars, go shine a flashlight into them (from both ends) tonight and you'll see that even a cheap optic can drastically change a light source. It's actually a fun little hack for making a searchlight when you're camping, you'll get a considerably brighter spot of light.
- tomatotomato37 7y agoWhy is everyone more concerned over the ability of someone with too much time and laser modulation equipment telling their smart speaker to order 10 crates of hand sanitizer than the physics & possible new applications of influencing microphones via laser light?
- amhokies 7y agoMoney is important to people.
- RandomGenerated 7y agoGreat... Laserfake tapes now... Juuust great
- Maximus9000 7y agoBecause it's about more than just buying stuff. Potentially you could say "Hey Siri, transfer all of my Monero coin to XYZ address".
- duxup 7y agoHow about telling their smart speaker to complete a task that might be connected to more sensitive things, like unlocking a door, opening a garage door?
- rubberfish613 7y agoThey also point out they can use this to bypass security and open "smart-locks".. this is slightly more concerning than just buying hand sanitizer.. I wouldn't be caught dead with one of these smart-lock devices, but I have friends who aren't so cautious.
- ptasci67 7y agoI have owned several smart locks and every single one has required a secret passcode to actually unlock via a smart assistant. Working backwards, the real threat if they didn't do that is just someone shouting through the window.
- jimrandomh 7y agoTitle is editorialized, and in a way that adds incorrect information (the supposed $14 price tag). Mods, the title for this should be "Light Commands: Laser-Based Audio Injection Attacks on Voice-Controllable Systems".
- gok 7y agoThe authors seem to a little confused by the purpose of voice identification in these systems. They repeatedly call it "Voice Authentication", which is it not.
- kinnth 7y agoBlew my mind! I always felt all these assistants we're super creepy any way and I get a lot of things hooked up in my smart home but want to control everything via my phone, which I trust.
- frankus 7y agoI'm curious if you can use the same effect with human/animal eardrums.
- bjt2n3904 7y agoOne thought is that the radiation is causing the MEMS sensor to physically vibrate. Part of me wonders how much of this is similar to the way the Raspberry Pi would glitch out when hit with a camera flash. [1] - https://www.raspberrypi.org/blog/xenon-death-flash-a-free-physics-lesson/ https://www.raspberrypi.org/blog/xenon-death-flash-a-free-ph... [2] - https://www.youtube.com/watch?v=SrDfRCi1UV0 https://www.youtube.com/watch?v=SrDfRCi1UV0
- dvdvdjdvd 7y agoNot very similar. The flash going off gives off strong EMF that induces currents in conductors at relatively low frequency. The photo-acoustic effect is usually a thermal effect. Material gets rapidly hot from the laser and cools quickly when the laser is turned off.
- inetknght 7y agoDiscussion yesterday: https://news.ycombinator.com/item?id=21444928 https://news.ycombinator.com/item?id=21444928
- zenlibs 7y agoWhile the attack is technically feasible, complexity and sophistication do not lend this to wide deployment. Someone with a lot of time, money and drive (think heist movie, or spy agency) to hack a person of interest might find this attack viable, assuming they find a line of sight to the mic. But if one's dealing with determined hackers, there is likely a multitude of other lower hanging fruit to first pick off.
- darzu 7y agoHacks always start as "infeasible". But eventually the technique is refined and there's a kit for $20 that can let anyone do it by following simple instructions.
- dwoozle 7y agoI forget where I read about a very early and simple attack on Amazon Alexas. Some people knew that their neighbors were going on a long vacation. So they just shouted into their house orders for the Alexa through the front door. They ordered tons of expensive shit on Amazon which was delivered to the front door and then ran off with the packages. The family didn’t get the order confirmation emails from Amazon since they were on a remote trip with no Internet access.
- aazaa 7y ago> ... We thus attribute our light-based signal injection results to mechanical movements of the microphone’s diaphragm, which are in turn translated to output voltage by the microphone’s internal circuitry. Aside from the security aspect, this is a pretty cool example of applied physics. The paper doesn't appear to report anything else on this effect, but AFAICT, it's new. The Wired story described two hypotheses, one of which involved the laster heating the air immediately above the microphone, simulating a sound wave as the light amplitude is modulated.
- dvdvdjdvd 7y agoNaw, the photo acoustic effect is a 150 years old
- nsxwolf 7y agoI suppose the next generation of MEMS microphones can contain photodiodes to mitigate this attack.
- BicepGlue 7y agoThis attack method should be dubbed the "Mysteron Attack". https://www.youtube.com/watch?v=Vs13rCqfH9k https://www.youtube.com/watch?v=Vs13rCqfH9k https://en.wikipedia.org/wiki/Captain_Scarlet_and_the_Mysterons https://en.wikipedia.org/wiki/Captain_Scarlet_and_the_Myster...
- deleted 7y ago[deleted]