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Cell Phone Encryption Exploit Demonstrated
Posted by
Soulskill
on Fri Feb 22, 2008 02:09 AM
from the wiretapping-on-the-cheap dept.
from the wiretapping-on-the-cheap dept.
Saxophonist brings us a story from Forbes about security researchers who demonstrated a new method for breaking the encryption on GSM cellular signals. The presentation was made at the recent Black Hat conference, and it's notable for the fact that the technique only requires "about half an hour with just $1,000 in computer storage and processing equipment." The researchers also claim to have found a faster method, which they intend to market for $200,000 - $500,000. Quoting:
"Undetectable, 'passive' systems like the one that Muller and Hulton have created aren't new either, though previous technologies required about a million dollars worth of hardware and used a "brute force" tactic that tried 33 million times as many passwords to decrypt a cell signal. All of that means, Hulton and Muller argue, that their cheaper technique is simply drawing needed attention to a problem that mobile carriers have long ignored--one that well-financed eavesdroppers may have been exploiting for years. 'If governments or other people with millions of dollars can listen to your conversations right now, why shouldn't your next-door neighbor?' Muller says."
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because (Score:2, Interesting)
Assuming I'm the person they're talking about instead of to...because my neighbors don't have anything interesting to say. Trust me, they're really strange and really boring. Anyway, for those of you wondering what someone could possibly say over a cell phone that's so intercept-worthy, some fancy banks require a key-press or auditory password to access balances and ev
Re: (Score:2, Insightful)
What a stupid comment. In other words, if some people are going to break the law, let's make sure everyone can. Good idea.
not stupid after all (Score:5, Insightful)
Parent
Re:because (Score:5, Insightful)
Parent
Re: (Score:3, Funny)
It's really a matter of publicizing the weakness to the point where manufacturers and network providers are forced to do something about it. Average people generally don't care about issues like this until they're really an issue.
Well, as you rightly say, most people don't matter in the grand scheme of things. At least that's how it can appear. But in oppressive countries, it's the occasional person in the occasional 'situation' where this stuff really matters, including (and especially) government interception. From that point of view, everybody matters, because if there are no trees (you and me), then there is no forest for fugitives to hide in. Never use a mobile phone, a land-phone, an unencrypted internet connection, etc. for
Re:because (Score:4, Informative)
So GSM crypto even if it was uncrackable is not very helpful if you're really trying to hide your comms.
Someone I knew once claimed to have extra crypto on his GSM phone so that he could talk "securely" to other people similarly equipped.
Parent
Let him be... (Score:4, Insightful)
What a stupid comment. In other words, if some people are going to break the law, let's make sure everyone can. Good idea.
Parent
Re: (Score:3, Informative)
Re: (Score:3, Informative)
~Dan
Re: (Score:3, Interesting)
Re:because (Score:4, Insightful)
Not really. What could you do with his telephone (or online) banking PIN? My credit union's online banking allows the following activities: Transfers between sub-accounts (savings, checking, etc), loan payments, bill payments, check images, statements and direct deposit adjustments (this much into savings, this much into checking, etc, etc).
Nothing within my online banking would allow you to "move all of my money away". I suppose you could setup a payee in bill payer for yourself, but even at that my credit union wouldn't allow you to directly supply the ACH information -- they'd mail you a check -- and even at that it would take a few days to get the custom payee setup.
Don't get me wrong. You could screw me pretty badly -- moving all of the funds from my checking account into savings would cause transactions to bounce if I didn't catch it.... But you couldn't drain my account and walk away with the funds for yourself.
Parent
Re: (Score:3, Interesting)
That's not how voice verification technology works. If it did, it would be totally useless.
Typically, voice sample are requested at random (out of a defined set - like the number 0 through 9) and sane engines look at how the phonemes are strung together when you say something, for example, in the middle of the phrase as opposed
Not too afraid (Score:4, Insightful)
While this is an extremely powerful re-discovery, I'm not that afraid of average Joe attempting to listen to my conversations, which are boring if anything most of the time. It would still probably take a reasonably quick computer and technical know-how to implement this kind of scheme on a usable scale. Plus, if the FBI and CIA already have the privilege to tap into my conversations, then the fear of security loss is already somewhat of a non-unique one.
Re: (Score:3, Interesting)
Re:Not too afraid (Score:4, Informative)
Yes often, even when at work. Its also no secret that I hate my top boss.
Lying on taxes is pretty much a national trait around here (Denmark), so again yes - some of us have no worries.
But I do despise the fact that someone can listen in on stuff, even though most of what we do is no secret, its still something that annoys me.
Parent
Forbes obviously missed Shmoocon... (Score:2, Interesting)
The presentation will probably be available on the Shmoocon website in the not too distant future. Forbes did the standard mainstream media muddling so check with H1kari for the real deal...
Overkill for neighbours (Score:5, Funny)
Re:Overkill for neighbours (Score:4, Funny)
They're also saying "ghob" out loud... also I think my other neighbors are raptors...
Parent
Re:Overkill for neighbours (Score:4, Funny)
2. Open subspace diplomatic channel to the Romulans [wikipedia.org].
3. Sell the conversations as intelligence data.
4. Profit!
Parent
Fabricated recordings (Score:3, Funny)
There never was end-to-end encryption... (Score:5, Insightful)
--
Electronics kits for the digital generation. [nerdkits.com]
Re:There never was end-to-end encryption... (Score:5, Informative)
Parent
Re: (Score:3, Insightful)
Re:There never was end-to-end encryption... (Score:5, Interesting)
That's a very good question.
One idea I've heard is that when SSL was first developed, the web was in its infancy and nobody really felt happy about the idea of sending their credit card details over it. The fact that it was relatively easy to eavesdrop on a computer network was fairly well known. This was no good to anyone who wanted to do business (OK, porn sites) over the web, and so SSL solved that problem by providing reassurance that nobody was eavesdropping.
The telephone system, on the other hand - that's been around so long that it's familiar technology and relatively few people are aware of how insecure it is. If you think GSM is bad (it's actually not that poor, and 3G introduces AES encryption), consider your land line. No encryption whatsoever and an analogue signal (so no computer equipment or specialised unusual codecs required to tap) between you and the telephone exchange.
Parent
Re: (Score:3, Interesting)
consider your land line. No encryption whatsoever and an analogue signal (so no computer equipment or specialised unusual codecs required to tap) between you and the telephone exchange.
Well, FWIW, you can detect a bug like that on your POTS line by monitoring the voltage on the line. It won't help you with a bug placed at the exchange/central office, but that vulnerability exists regardless of the technology (POTS, GSM, VoIP, etc) that you are using.
More amusing then deliberate bugs is crosstalk on old/lousy wiring. I never had POTS hooked up in my old apartment building (cellular only) but I could plug a phone into the jack and listen to other peoples conversations/DTMF/dial tones.
Re: (Score:3, Informative)
How is it that it caught on for the web (credit card payments over SSL), but still barely for personal communications
Because someone is losing something tangible (i.e. money) when fake credit card payments go through. The users didn't demand it, credit card companies did, to prevent skyrocketing fraud losses. Users themselves have never truly demanded encryption - how many online shoppers do you know that are savvy enough to look for proper SSL encryption before typing in their credit card number?
Re:There never was end-to-end encryption... (Score:5, Insightful)
the browsers come pre-equiped and will use it when ever a url starts with https rather then http.
also, the encryption isnt used to verify that whoever is sitting in front of the computer is who he or she claims to be, for that you have third party stuff like pads of one time codes, code generators and similar.
for im and mail on the other hand one have the, in the eyes of the non-techie user, laborious process of generating and exchanging keys, and making sure that the keys belong to the person one wants to communicate with.
only way i see this change is if we could turn the mobile phone into a digital key carrier. meet someone, exchange keys pr phone just as one would exchange phone numbers, im/mail address and similar, and so on.
or maybe the social network sites should allow one to upload ones public key just as on enter above numbers and addresses?
basically one have to find a way to bring the exchange of public keys into the fabric of ones social interaction. sadly i dont think that will happen any time soon...
Parent
Re: (Score:3, Insightful)
There are stories like this all the time, but tech people still have trouble convincing most users that end-to-end encryption is important.
I think -- and I have no scientific basis for this, but it'd an interesting area of study -- that the answer could be that humans simply haven't evolved to understand the threat. If you live in a small pre-technological tribe then it's easy for your brain to figure out when you're being watched, when you might be being watched, and when you're definitely not being w
Obligatory (Score:4, Funny)
Because the Government hates the competition?
GNUradio is also up to GSM cracking (Score:5, Informative)
check out some movie about the GSM state of security [1] and mod me informative.
[1] http://chaosradio.ccc.de/camp2007_m4v_2015.html [chaosradio.ccc.de]
Coming soon, try it yourself... (Score:4, Interesting)
I'm wondering how you ever could tune in to the correct conversation, with thousands of mobile phones transmitting at the same time.
Bert
Re:Coming soon, try it yourself... (Score:4, Informative)
This number is usually printed on the phone somewhere under the battery cover & is retrievable from the phone's software.
Parent
Re: (Score:3, Informative)
Breaking a conversation would mean calculating KI somehow, which is a 128bit key locked in the SIM and not retrievable at all. UMTS is even more secure (provides protection against MIM attacks, more keys, etc.)
Here's your answer. (Score:5, Insightful)
Re: (Score:3, Insightful)
Privacy the least of our concerns (Score:5, Insightful)
From my understanding though, this encryption is certainly not applied over the whole transmission, meaning endpoint to endpoint. Just the handset to the tower.
The government does not actually need to crack this encryption, or even intercept transmission between handsets and towers. They can just order digital wiretaps, which cannot be detected. Speaking of which, I have always been amused when people state they you can just buy hardware to detect that too. The location of the handset is easily determined, and in most cases the identity of the user. The government already has the ability to access all of this information with the cooperation of the telecommunications companies anyways. With Telco Immunity being pushed, there won't even be room to dispute it anymore.
So not trivializing the serious issues with our privacy and the government, they are still the least of our concern here.
What strikes me as very problematic is that this opens up a whole new "market" for identity theft, banking fraud, etc. I do quite a lot of business over the phone, and just about every single company uses the touch tones to gather data. Capturing the the numbers by listening to the tones is trivial. This can be done quite easily by software and hardware.
So if all the popular company phone numbers are known, and all the data being sent to it by customers can be recorded, this presents quite a security problem. With the right amount of equipment you can start capturing all sorts of data being sent over the phone. It will only be a matter of time before you gain enough information to compromise someones identity.
I am not worried about my neighbors, not worried about my government, but I am very worried about the stranger interested in the fact I called Washington Mutual.
Re: (Score:3, Funny)
Re:Privacy the least of our concerns (Score:4, Insightful)
Parent
Re: (Score:3, Interesting)
CCC (Score:3, Interesting)
http://video.google.com/videoplay?docid=8955054591690672567&q=CCC+GSM&total=2&start=0&num=10&so=0&type=search&plindex=0 [google.com]
Lets look at some facts.... (Score:5, Informative)
New GSM equipment already supports A5/3 [gsmworld.com] which is still secure. I think the main impact of this hack is going to be some sensational headlines and a big push to make A5/3 universally available.
Re: (Score:3, Interesting)
that their cheaper technique is simply drawing needed attention to a problem that mobile carriers have long ignored--one that well-financed eavesdroppers may have been exploiting for years
Clearly the carriers haven't ignored this problem - they have produced a better encryption algorithm in the form of A5/3. The real problem is that the governments hold the carriers over a barrel. If the encryption gets too good then the algorithm is subject to all kinds of export restrictions which makes it very difficult to use in a global standard like GSM.
I thought this had already been done? (Score:3, Informative)
iPhone (Score:4, Funny)
Re: (Score:3, Interesting)
Whenever the phone you were scanning moved from one cell to another you'd lose the signal but it would display on the screen what channel it had changed to.. in hex.. so you'd either convert the hex to decimal, enter that channel and pick up the conversation or you'd scan for another call.
And yes, it was boring as hell.
Re:That would be awesome (Score:5, Insightful)
Parent
Re:That would be awesome (Score:5, Funny)
Parent
Re:For those three people ... (Score:5, Informative)
Parent
Re: (Score:3, Informative)
3G coverage in most of the developed world is significantly worse than GSM - your 3G phone will drop back to GSM mode in poorly covered areas. Not to mention that most of the undeveloped world uses GSM almost exclusively.
(I also hesitate to point out, for risk of starting a flame war, that a certain recent over-hyped phone only does GSM)
Re:For those three people ... (Score:4, Informative)
Parent