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iPhone Attack Reveals Passwords In Six Minutes
angry tapir writes "Researchers in Germany say they've been able to reveal passwords stored in a locked iPhone in just six minutes and they did it without cracking the phone's passcode. The attack, which requires possession of the phone, targets keychain, Apple's password management system. Passwords for networks and corporate information systems can be revealed if an iPhone or iPad is lost or stolen."
Give them a break! It's not like they have billions of dollars in annual profit which could help them do some serious security R&D.
vos nescitis quicquam, nec cogitatis quia expedit nobis ut unus moriatur homo pro populo et non tota gens pereat.
In IOS >4 with a modern device (3GS or better, iPad included) this article is blatantly incorrect.
"The attack works because the cryptographic key on current iOS devices is based on material available within the device and is independent of the passcode, the researchers said.". Not true. In iOS4 they use a variant of PBKDF2 to generate an encryption key that is used along with the device key alluded to in this article to decrypt "class keys". The class keys are then used to access data at the various protection levels (Never, After First Unlock, Only When Unlocked). Each of those levels of data has a separate key. Those keys are required to decrypt the individual keys on each file. Each file has an encryption key set on it in the meta data (which means you do have to reformat your system and set a reasonable passcode).
Because of the PBKDF2 variant brute forcing is infeasible. Because of the device key you have to try this IN the device and are limited to Apple's hardware for forcing.
All of this is possible because Apple has an AES-256 hardware chip that blazes through crypto for that algorithm.
Remote wipe uses yet another key (the file system key). So each file encryption key requires a "Class key" and a "file system key" to be decrypted. Lose either one and the file system is history. So remote wipe is accomodated in newer versions of iOS by just forgetting the file system key.
In short, this article is not providing an accurate portrayal of "current/latest" devices. Though I am not sure how many people: Have the newer hardware, have iOS 4 AND have reformatted their filesystem to accomodate the required metadata.
For a buddy's bachelor party we went white water rafting, and rented a huge cabin for the weekend. When we first arrived, we were all staking out beds (18 of us), and some of them were of the slide under the couch futon variety. While we were pulling one out, we found a woman's wallet from the previous occupants. It belonged to a girl in her early 20's that was clearly there partying it up. Her wallet contained everything, ID, credit cards, iPhone, etc.. (even a little white baggy of nose candy). Anyway the iPhone was locked, but one of the guys took it and said (his words not mine) "lets see how dumb this bitch is...". He typed 1,2,3,4 into the iPhone and nothing. Then he said, hey hand me her ID (which all the guys were checking out as she was rather hot), and then typed in her birthday as found on her ID into the iPhone... Click. Two tries. Her phone had plenty of photos of her and her girl friends which we all checked out. Anyway in the end we flushed her baggy, and using the contacts of her iPhone called up her Mom and some of her friends to get hold of her, told her we found her stuff, got her address and at the conclusion of our weekend mailed her stuff back to her. When we talked to her on the phone, we suggested she change her password to something a little stronger.
Moral of the story, 1) People pick stupid passwords anyway, you hardly need some sophisticated password cracking system in many cases, 2) don't loose your iPhone with a stupid password at a party resort unless you want a bunch of stupid guys ogling your photos... We also may have taken a photo of one of the guys on the toilet using her phone, not sure if that ever got erased or not...
OR you could read the PDF which states CLEARLY:
"The results were taken from
a passcode protected and locked iPhone 4 with current firmware 4.2.1. "
That is the latest iOS and the latest iPhone, mind you.
http://www.sit.fraunhofer.de/en/Images/sc_iPhone%20Passwords_tcm502-80443.pdf
The data decrypted isn't arbitrary. It's information the phone requires when it starts up. Therefore the phone itself has to have some way (usually protected by root privileged objects) to unlock that information.
Any phone, or computer for that matter, that has automatic login enabled has to make this sacrifice. The iphone auto logs in as user "mobile". OS X (and therefore iOS) has a very convoluted/obfuscated way to unlock the user keychain based on automatic login, but of course no matter how much they obfuscate it, it can be defeated given enough time and dedication, by people that are capable of reverse-engineering your binaries.
This isn't a security blunder by Apple, it's a necessary tradeoff made by any operating system that features auto login. The only way to strengthen this is by encrypting the actual key with the unlock code, but four digits isn't enough entropy to even be worth the effort. You might turn a 6 minute hack into a 7 minute hack if you're very lucky. And as others have pointed out, that's about as much inconvenience as users will tolerate in an unlock code.
I work for the Department of Redundancy Department.