Slashdot Mirror
Cell Phone Encryption Exploit Demonstrated
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."
and i'll bet they won't charge anything.
;)
check out some movie about the GSM state of security [1] and mod me informative.
[1] http://chaosradio.ccc.de/camp2007_m4v_2015.html
Ya know, it *is* strange. Take, for example, Pidgin (formerly GAIM). There's about two dozen plugins for it. One of the plugins is Pidgin-Encrypt which does everything that you would expect (except possibly for some sort of certificate system) and is about as secure as ssh. Does it come with Pidgin by default? No. Is it enabled by default? No. Why not? Why is encryption still considered some opt-in alternative? Considering that it takes both parties to consciously choose to install this plug-in, the grand total of people who use it is about 10.
How we know is more important than what we know.
Newsflash - most of the world outside the US uses GSM.
This number is usually printed on the phone somewhere under the battery cover & is retrievable from the phone's software.
[Fuck Beta]
o0t!
It didn't "catch on" for the web, it was mandated by the Federal Government (in the US at least). See PCI (Payment Card Industry) for a little quick and dirty education on the matter.
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?
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.
Actually, the pass phrases are generally use once and discard. They are generated on demand or pre arranged.
"If the King's English was good enough for Jesus, it's good enough for me!" -- "Ma" Ferguson, Governor of Texas (circa
~Dan
An SQL query goes to a bar, walks up to a table and asks, "Mind if I join you?"
New GSM equipment already supports A5/3 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.
Being able to crack the GSM A5/1 encryption with thousands of US dollars (instead of millions) is nice, but the encryption scheme itself was cracked long ago, and by Prof. Shamir (of RSA fame), no less.
The right to offend is far more important than the right not to be offended. (Rowan Atkinson)
In a capitalist society such as America, why should a private individual with a lot of money have fewer rights than the government with money?
-1 not first post
No, most of the developed world already has a 3G infrastructure. Only technological backwaters like the US still use GSM.
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)
http://blog.nexusuk.org
IMEI is not transmitted cleartext. In general conversation even the IMSI is only transmitted once for billing purposes and then obfuscated for the rest of the conversation (a temporary IMSI is generated from the real one which identifies the conversation without giving away any private information).
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.) and AFAIK there's no theoretical attack against that, so you don't need to worry if you're using a modern phone (with one notable exception of course).
Don't you mean 2.3 billion people? I mean, over 80% of the world's cell phones? The world doesn't end at your doorstop, you know?
Slashdot, fix your code or at least hire someone who is competent at it to do it for you.
Looks like he gave the same (or longer) presentation at Black Hat.
http://cuz.cx/
Regarding government interception, GSM encryption is only from phone to station. At the Telco it's plaintext. So govs can (and probably do) listen to GSM phone calls. Should be common knowledge amongst telco people.
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.
New Scientist described a practical, fairly low budget attack in 2002. By use of selective jamming, it's possible to drop a handset off the cell, then capture its IMSI (and thus IMEI) when it re-registers. Using these stolen credentials, send a spoofed degraded signal to the base station to mimic poor reception; by design, GSM then switches to A5/0 i.e. turns encryption off(!) because an unencrypted signal needs less bandwidth. If you don't have a specific target to eavesdrop on, you could presumably lower the budget further by just monitoring somewhere with naturally bad reception ...
The article stated this technology was commercialised as the "IMSI catcher", but it seems that they've updated it to instead mimic a base station, which "forces" handsets to use it by virtue of being the strongest signal then selects A5/0 mode. (The fundamental GSM flaw here is that the phone must authenticate to the network, but not vice versa.) This new method is probably due to network complaints about the interference to everyone the first method causes.
Your position is basically a "who cares if i have nothing to hide" attitude. Bruce Schneier has an excellent writeup about the value of privacy here:
http://www.schneier.com/blog/archives/2006/05/the_value_of_pr.html
Basically, privacy is a right, not a privilege. It is not something that should be easily given away.
To answer your question, the idea is that other friendly governments (UK, Australia) do the eavesdropping on the US's behalf. The US does the same for them. They then share the information with each other. No laws were violated, and this is completely "legit".
Not sure if you've heard about echelon, but much of this global surveillance system is already in place today.