Is My MacBook Pro Always Listening?
brianpress.heroku.com
brianpress.heroku.com
So what if the panel actually even disabled the mic preamp on the board? You could have a program/virus/trojan that silently re-enabled it behind your back, without you knowing. So I'd say this is nothing to be concerned about, because every device you own potentially "listens" with its microphones all the time.
The advice with plugging a jack into the line-in port is good -- if you're sure your hardware hasn't been tampered with, this should physically disconnect the microphone.
Obviously if you're really worried about your computer listening, you should rip it open and physically cut the microphone connection.
Why so? Most soundcards merely detect an impedance change and flick a bit to switch from internal microphone to line-in but you can have full control of that bit by software. That's actually what the prefpane does: even with something plugged in the line in, one can switch back to the internal microphone as a source. (EDIT: apparently it goes hidden on new hardware revisions but the functionality is there, just boot into Linux and do some poking on the soundcard to see what's really available)
For example, Apple headphones for your iPhone can be plugged in and used for that purpose...
There is no way in software to disable that LED.
The reason is because we can only focus on one thing at a time. While waiting for the picture I was casually browsing the net -- probably reading HN -- and only periodically looking up to watch the light. I assumed a light source would catch my peripheral vision. It had not. For the third test I stared at the camera with an unbroken focus. Sure enough, the light turned on as expected.
Net: I could not see the light unless /I was looking at the camera/. It's a side effect of how the mind works and processes information. It's also important to keep this fact in mind when building interfaces: don't alert users in places they aren't looking. They won't see it no matter how red or many sparkles you add. :)
Even then, let's assume the sound card is always on (like my old SB16):
- what would listen to it if it was on? necessarily some code, or else it just goes straight to /dev/null.
- so if it's external code injected by a malicious guy, what prevents him from setting it back to internal (and setting it back to line-in when you're looking)? Or craft all sorts of drivers hooking into or replacing AppleHDA.kext or whatever?
- but if it's not external code it has to be internal (i.e Apple provided), so what would prevent Apple to simply tell you it's off when it would not actually be?
- and since line-in disappeared but the (HDA or whatever) sound chip certainly still has this functionality, what would prevent Apple from having a second microphone plugged into that line-in, completely hidden and uncontrollable?
Now Poe's Law kicks in and I can hear headlines already "Apple removed the line-in on purpose to spy on us!"
Without removing the hardware there is no way to prevent someone with remote root access from recording audio from any input regardless of settings. This is true of any machine that has audio inputs and drivers loaded for those devices.
Really, what I see is a software update that fixes a user interface bug. System Preferences no longer offers disconnected audio inputs as a selectable option, because it's just plain smarter that way. Could there any possible confusion for an average user between "Internal Microphone - Built In" and "Line In - Audio Line In" when looking at their sound input options? Seems like a design decision made in the interest of removing irrelevant choices.
The consumer product line continues to have fewer fine-grained controls than Pro products, so nothing has really changed here.
To get technical, you are controlling the gain of the volume of the stage after the microphone. So in the real world the microphone should always show input unless physically disconnected. Computer manufacturers don't follow any standard practices it seems, so you may see it both ways.
So it's not a trivial thing to bypass, but it's not secure. Use a sticker or post-it note if you're paranoid.
It always means misinformation, not just today.
If you don't want your computer to be used as a listening device, first try adjusting your tinfoil hat. If you're still worried, open it up and remove the speakers and microphones. Make sure you get them all! Though I'm sure someone can figure out how to make a hard drive into a microphone, so you'd better replace that with an SSD. Also get the camera while you're in there.
There. Now you just have to worry about the bugs the Agents put all over your house.
Physical bugs are expensive. Malware is cheap.
Working in telecom was enlightening for me. There's a feature called "executive barge in" that pops up from time to time when shopping for PBX systems. Executive barge in allows a user with the appropriate rights to open an audio channel to any phone connected to the switch, bypassing the alerting phase. That is to say, the phone never rings; the audio channel just opens. Most systems provide some sort of brief alert tone, but this is entirely implementation based. There's nothing implicit about opening a channel that would require a tone.
All digital phone systems have the ability to implement a feature like this. Cell phones are digital phones. With old analog (POTS) phones, when the phone was "on hook", there was a physical change in the connection of the copper pairs. In modern phone systems on-hook/off-hook is just a software state. There is no physical difference. Opening an audio channel is a distinct event, completely separate from the alerting signal [1] in common cell phone protocols.
The bottom line is that if you're really concerned that someone is listening in, you should watch the horrible movie "RED" and imitate John Malkovich's character the best you can.
http://www.euronet.nl/~rembert/echelon/muren/index.html#floo... (dutch)
Newer phones, basically anything with a bunch of electronics are not susceptible to this kind of trick.
When it was first revealed by the dutch hacker group 'hack-tic' (http://en.wikipedia.org/wiki/Hack-Tic) the phone company denied it could be done until there was a public demonstration.
The distinction is in the type of phone attached to the POTS line. It looks like it requires a combination of a carbon mic and an old, non-integrated-circuit switchhook. Something like you'd find in an old Western Electric 2500 [1].
A carbon mic has some pretty unique properties. Base output is very high, such that output is easily detected at a distance without amplification, and they're very low impedance. Even slightly newer telephone designs would use an electret style microphone. The most basic electret circuits require a capacitor, which is noted to defeat the frequency flooding attack.
1 - http://en.wikipedia.org/wiki/Model_500_telephone#Model_2500
Me too -but in a more literal way.
Sorry for the downvotable comment, but cannot resist a pun, especially when it kinda makes my actual point.
The thing is, whether the MBP is "always listening" or not is of little consequence, in an age when we know that governments look into the wires, have taps into ISPs and can listen to any and all mobile phone conversation.
Btw, my iMac 27" 2009, doesn't seem to register any sound with the internal mic set to the minimum volume. And there's also the "Audio MIDI setup" program, where you can disable it completely.
http://en.wikipedia.org/wiki/Mark_Klein
http://en.wikipedia.org/wiki/Room_641A
http://en.wikipedia.org/wiki/Gsm#GSM_service_security
GSM uses several cryptographic algorithms for security.
The A5/1 and A5/2 stream ciphers are used for ensuring
over-the-air voice privacy. A5/1 was developed first
and is a stronger algorithm used within Europe and the
United States; A5/2 is weaker and used in other
countries. Serious weaknesses have been found in both
algorithms: it is possible to break A5/2 in real-time
with a ciphertext-only attack, and in January 2007, The
Hacker's Choice started the A5/1 cracking project with
plans to use FPGAs that allow A5/1 to be broken with a
rainbow table attack.That would be one crazy covert communications channel. Wonder if there are any security papers exploring that...?
[1] http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedback...
There might be a Kickstarter product in this. Simply devise a magnetic activation switch for the microphone. I've opened up multiple 13" Macbook Pro laptops, so I know how little space is in that corner where the microphone and magsafe socket board is, but there is enough.
Perhaps even better: a microphone that has a deactivation pin which can be pulled with a pair of tweezers. A service would solder this in place for you, and the laptop could be used with no internal microphone. Then, when it was time for you to sell the laptop, you simply open the case and pull the pin out of the back of the microphone, reactivating it. You could even construct this out of the same microphone element as used in the macbook. Just have the pin short across the mic capsule's terminals.
Let's say it's 2003 and instead of being a post about laptop internal microphones, it's about SQL injection vulnerabilities in [your favorite blogging engine]. The quick & easy response is "Oh, go adjust your tinfoil hat, do you really think you're important enough for the hackers to focus on? And if they do, don't you think they could do a little more than rely on a silly SQL injection vulnerability?"
But we know the problem with SQL injection vulnerabilities usually aren't focused hacker attacks, it's fire-and-forget script kiddie exploits that most of us have to worry about. This is no different. Not too many folks are worried about "the Agents" surreptitiously monitoring their laptop's microphone, it's some bored 14-year-old with time on his hands and an easy-to-use exploit tool.
Personally I'm not that worried, but I can see why this could be a problem for some.
If you're really paranoid, you could always remove the mic with a soldering iron... =)
If you're still OCD and concerned about it, install Soundflower [1] and you can easily configure Soundflower as your default input, but not feed anything on to the Soundflower bus, thus making the default input silence. This is, in effect, the same as the author's suggestion of setting the default input to line-in and plugging in a stub; also pointless, as a line-in jack has no ability to convert acoustic wave forms to electrical signals.
I feel less-smart for even addressing this question.
I don't know (no experience) if Macs' analog ports were this clever, but considering the hardware to detect presence in the port is trivial, it wouldn't surprise me so that's how I interpreted it.
I'll also link along http://roguemaobea.com. They produce a line of audio apps that can hijack and route sound in OS X for a range of actually useful purposes. They've got tools for doing timed recordings of system audio, Line in audio, or audio from specific apps, as well as a tool for broadcasting any of these audio sources to Apple's Airport Express.
It is made by the fine people who produced Max/MSP.
The internal microphone no longer shows up, suggesting it is disabled as before.
Thus, the simple plug hack should still work.
(I'm running Lion on a MBP8,1.)
Reducing the input level to zero suggests it's disabled but evidently this isn't the case.
I would imagine (yes, I'm speculating) that the control panel uses a standard OS interface to enumerate audio devices, and when the internal microphone drops off the list in the dialog, that reflects the fact the OS isn't offering it anymore. So an app asking the OS to enumerate audio devices would not find the internal microphone.
It's always possible that there's a lower-level hack to get around that, but then that's always been a concern.
By the way, I forgot to mention that when I turn my input level down to zero, the little blue bars stop showing any signal. The blog post is about 10.6 (Snow Leopard), as mentioned below the Control Panel snapshot. Maybe this is all fixed in 10.7 (Lion)?
Any software switch can be overriden by a silent hack. Besides, overhearing conversations is the least of your problems if your computer is compromised. I would worry more about documents and web browser data.
What evidence is there that this behaviour of the internal mic is the same when the Audio preferences pane is not open?
Could it be that the mic is automatically made 'live' when system preferences or that particular pref pane is opened?
However, if you're so paranoid that you think this could be a problem, you're already outside the realm of buying preassembled computers anyways. Who knows who could have tampered with it en route?
Cover the camera with your finger or shine a flashlight/mobile phone screen into it, watch the keyboard lights react. It's obviously listening for light level changes.
I just wonder how much data you could collect from the sensor without the green light turning on?
edit: I'm wrong, see my reply to jcromartie
Well now, what am I going to do with this tin foil hat I just made?
http://osxdaily.com/2010/05/22/where-is-the-ambient-light-se...
http://www.amazon.com/Logitech-3-5mm-Jack-Audio-Adapter/dp/B...
If your tin-hat doesn't feel like enough protection, try downloading and installing Sound Flower (Generally cool app). Basically it lets you 'patch' one audio output on the computer to an audio input, so you could record the output of your computers speakers at near full resolution (Useful for screen-casts/video game play through and probably lots of other things). Activate Sound Flower Bed and select the option along the lines of 'no input'/'no device'. Go into system preferences and select the Sound Flower device as the default input device.
All of that is, however, completely irrelevant since applications can select audio inputs external to system preferences and record the input at whatever volume they like. (E.G. Skype can use a different input to the sys default, Logic Pro can record from all you system inputs at once etc.)
The average user of any machine doesn't need to worry about this. Much ado about nothing.
If something like this bothers you theres no reason you should be using any closed source software at all.
It's that easy. If you're concerned about your privacy and system integrity don't use any software from a source you don't personally trust and that can't be reviewed by a third party.
ever thought about the camera or your mobile phone? ;)
Some of you people need to lighten up.
Besides, my favorite hat is made of copper! ;P
Can you imagine A the traffic that would take and B the amount of useless information that would be recorded. They have millions of computers!
If its not being recorded locally or sent to an external source from a privacy point of view there is no problem. Both of these would be easy to detect by looking for sound files somewhere on the device or monitoring outbound internet traffic.
So is it battery life that you have the problem with?
I didn't read any allegations of remote recording here. Perhaps you clicked on another article by mistake?
i tried this on my mid 2009 mbp, and dont get the same results... turing volume input all the way down should result in muted audio input. nevermind havkers... what if i just want it off for a sec while i say something i dont want someone to hear (mute buttons aside.... and are they working filly if rekying on the same api)
suggest trying on multiple units... and as others have said, those guidelines are just best practices, not guarantees. if you want guarantees, you dont have conversations near microphones... and sweep theroom for transmitters, assuming thats still possible. one would assume some agency with an unfathomable budget could probable fevelop some kind of ultra liw power ulta wideband bug we are nor goingto detect. or it will just record and theywill tell it to transmit later. or just pick it up... thelist goes on,
theoriginal question is valid though, i would like to know that, absentmalicious intent, when my mic is muted its muted, and inthe samevein, that the camera light is an absolute indicator of activity.
when i get around to buying a new mac (or something) which shoukd besoon, ill be doing someexploratory surgery n this one i think.