For context, a vacuum cleaner is also 75 decibels, with 80db as the threshold for hearing loss:
So you literally have to scream at each other right in front of the hard drive for it to record discernible speech. This is not an "eavesdropping mic" as the subheading of the article claims. Therefore, it's yet another clickbait BS fearmongering article about an interesting tech hack.
A vacuum cleaner is loud but not that loud. You don't have to scream over it. 80db will cause hearing loss if you listen to that level sustained over a long time, but it's not remarkably loud. In fact, the chart you link shows everyday examples of noises in that range like phones ringing, chamber music (from acoustic stringed instruments using resonant cavities, a good proxy for human voices), city traffic, and more.
While a 75dB noise floor is definitely a problem for obtaining a clean recording (the kind you hear in a tv show), it's nothing unusual in forensic work. The sound from the servos moving the heads back and forth will consist of aperiodic loud but relatively slow and brief transients. It'll be like trying to listen in to a space while a spastic Autechre track plays on a speaker nearby - hard work but not impossible. A more prosaic example would be trying to follow the words of an unfamiliar song or rap at a live concert.
I'm pretty confident that I could get what you said into your phone while you sat in front of your laptop with a mechanical hard drive, without even hearing any of their source material. I would find this easier than trying to deal with a bad recording made in high wind or in the vicinity of a diesel engine.
I don't think most people realize how good forensic audio tools are in. Cedar stuff is expensive because it works in realtime (sub millisecond processing latencies!) and can be operated by anyone who is capable of manually tuning a radio.
It's research clickbait basically.
Right. Because certainly no one can figure out how to improve this.
How about using multiple hard disks simultaneously and use signal processing magic to clean it up, just like microphone arrays do?
Maybe you could even start to get some limited spatial information about the surroundings, based on sound arrival time difference between multiple disks? Similar to the way reflections of sound waves in the Earth crust and below can be used to compute Earth internal structure. Or how bats navigate.
I'm not saying these ideas work — most likely not. What I'm saying, that someone with this knowledge and some brilliant discovery might be able to take this technique way further.
Good point. I guess you could accurately triangulate the position of the hard drive using seismic reference data, in the case of an earthquake. Or you could make loud noises at different places in a city, and locate the hard drive that way.
In a more civilian context, you have a nice fireworks show and then send the SWAT team.
It’s also really freaking cool, and an amazing way to make something that’s created for one purpose into a seemingly unrelated one.
But look, let's be real: for the vast, vast majority of people, this is all just a cunning academic exploitation of hard drive technology. No one's really going to bug you via your spinning rust.
The title is accurate. It's currently not the best or completely practical, but this type of attack will likely have room for improvement.
That's how people routinely talk in our open office, so entirely plausible.
But, "Attacks only get better."
It's not as simple as just combining them but yes, the second data point would be immensely helpful.
* A tool that can clear the noise from the hard disk, allowing a glimpse at some parts of the conversation
* When the computer is turned-off (assuming the listening device can stay on)
* Some areas in an Airport
* Construction areas
It is not impossible to be useful for some actors, but it does require specific conditions.
It is all just another nail in the "spinning rust" coffin imho: A novel technique applicable only to a declining target base.
I'll update if a band plays tonight.
I had no idea you could get as much as 4KHz of frequency bandwidth out of those sensors. That is a pretty cool result.
I've often wondered what sort of physical problems the people who engineer hard disks deal with, whether they have problems with micro-turbulence and suchlike.
I think this is kind of a basic thing that once you know it, you see the possibilities almost everywhere, where you understand how electrical fields can be generated with physical interaction. Transportation of the sensing then becomes the next problem to solve.
Interestingly, the audio chipsets in modern motherboards and sound cards include an option to change the function of an audio port at the software level, a type of audio port programming sometimes referred to as ’jack retasking’. This option is available on most audio chipsets (e.g., Realtek’s audio chipsets) integrated into PC motherboards today. Jack retasking, although documented in the technical specifications, is not well-known . For an in-depth technical discussion on malicious retasking of an audio jack, from the hardware to the operating system level, we refer the interested reader to the following previous work .
Mordechai Guri and Yosef Solwicz and Andrey Daidakulov and Yuval Elovici. 'MOSQUITO: Covert Ultrasonic Transmissions between Two Air-Gapped Computers using Speaker-to-Speaker Communication'. arXiv preprint 1803.03422v1 [cs.CR], 9th March 2018.
Mordechai Guri and Yosef Solewicz and Andrey Daidakulov and Yuval Elovici. 'Speake(a)r: Turn speakers to microphones for fun and profit'. 11th USENIX Workshop on Offensive Technologies (WOOT 17). USENIX Association, 2017.
Blog post by author from 2011: http://voices.canonical.com/david.henningsson/2011/11/29/tur...
I believe similar utilities exist on Windows at least with some cards.
One day, in order to comply with some law or other, the company upgraded the security system, renovating the space such that it was enclosed in bullet-proof glass panels, required a key-card to enter, had an operator at all times (24/7), etc. They installed a Halon fire suppression system, and a gigantic alarm horn to function as a company-wide alert.
Well, the day it was all set up, it was time to test it all - Halon test dump, done (very expensive test). Operator still alive (had to use an oxygen mask), done. Alarm siren test: done. Okay, back to work .. hang on .. all of the systems are down .. what's going on ..
Yes, the siren was so loud, and had been positioned close enough to the bullet-proof walls, that the focused energy it created had crashed the disks. ;)
That was a very expensive renovation. Fortunately, we got the 'restore from last backup' test done pretty quickly ..
Although it is a cool experiment and POC. A few years ago I took apart 5 HDD's to see if I could make a usable speaker (as a desk/novelty thing). 2 of them worked, one of them worked with decent fidelity. Three failed (probably my fault). The one that worked was a literally massive double-5.25" Maxtor.
It wasn't really a problem; we only noticed because we couldnt get a signal out of our circuit due to a busted internal lead connection, but we noticed the changes as people walked past. Was curious.