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Security Wireless Networking Hardware

New Way To Crack Secure Bluetooth Devices 137

Posted by Zonk
from the mind-what-you-say dept.
moon_monkey writes "Cryptographers have discovered a way to hack Bluetooth-enabled devices even when security features are switched on, according to a report from New Scientist.com. The discovery may make it even easier for hackers to eavesdrop on conversations and charge their own calls to someone else's cellphone. From the article: 'Our attack makes it possible to crack every communication between two Bluetooth devices, and not only if it is the first communication between those devices,'"
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New Way To Crack Secure Bluetooth Devices

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  • Show me the code (Score:2, Interesting)

    by Anonymous Coward

    where are these cryptographers and their code ?
    and why isnt this mentioned on Butraq or Full Disclosure ?
    • Re:Show me the code (Score:3, Informative)

      by moyix (412254)

      Well, here [tau.ac.il] might be a good place to look. The article doesn't actually tell you where to find the research, but it was posted on Schneier's blog this morning.

      Cheers,
      Brendan

  • Funny quote (Score:4, Insightful)

    by MyLongNickName (822545) on Friday June 03, 2005 @02:24PM (#12716326) Journal
    "Too many people are thinking of security instead of opportunity. They seem more afraid of life than death. -- James F. Byrnes"

    At bottom of Slashdot screen :)
  • by plover (150551) * on Friday June 03, 2005 @02:24PM (#12716328) Homepage Journal
    By forcing a re-pairing (as stated in the article) does it then rely on the user to re-pair his devices as a manual step? Or does this re-pair process happen in an automated fashion?

    If it's a manual step, then it'll require education of the users to not pair their phones in public.

    • From TFA:

      Wool and Shaked have managed to force pairing by pretending to be one of the two devices and sending a message to the other claiming to have forgotten the link key.

      So, it's an automatic and remote attack which doesn't rely upon any cooperation from either of the two original Bluetooth devices.

      • The way I originally read it I didn't understand if this forced pairing required the input of the user to perform a "pairing" manually, (which was then intercepted by the attacker) or if the devices just agreed automatically to resend their pair information (which was then intercepted by the attacker.)

        Thanks for the clarification.

      • by Sancho (17056) on Friday June 03, 2005 @02:37PM (#12716461) Homepage
        The article isn't clear.

        They imply that part of the pairing process is inputting the 4 digit PIN. If this is the case, user intervention would be required for re-pairing. Maybe the article wasn't as precise as possible regarding the process, but it distinctly uses the above terminology which, to me, implies manual input.

        Perhaps the devices remember the PIN if the link-key is forgotten, thus removing the need for user intervention? That would explain the bit in the article about trying every PIN (a 4-digit PIN seems pretty ridiculously small, regardless).
      • by MadRocketScientist (792254) on Friday June 03, 2005 @02:39PM (#12716480)
        Digging up their paper [tau.ac.il], it seems that it is not automatic:

        If the attack is successful, the Bluetooth user will need to enter the PIN again - so a suspicious user may realize that his Bluetooth device is under attack and refuse to enter the PIN.
        • Ahh! Thank you for the link to the actual paper! (TFA suggested to me that since they were presenting it at a conference next week they hadn't published it yet. Yet another misread by me. I'm two for two today!)

          So I really am safe as long as I'm not entering my PIN in a place where I can be eavesdropped upon. No worries! Whew.

    • It would seem that way.

      How does this work with headsets? Where do you enter the PIN on the headset? Or do you ONLY have to do it with the phone?

      Also, I hear that some phones do an autonegotiation that doesn't require a PIN at all. It would seem that these would be the most vulnerable to the attack, although what happens when the legitimate device tries to pair at the same time as the spoofer?

      Regardless, at the very least this looks like it could be a DOS.
      • The headsets I'm familiar with have a preset PIN (something like 0000 or 1111) that you have to enter into the phone. But they can't initiate the pairing process -- it has to be driven from the phone side. I suppose it's entirely possible for an attacker who sees you use a headset to set up his device to sniff your headset's ID, then pretend to be that headset with PIN 1111.

        Now a headset has only a limited set of functions it can perform -- they can't dial digits without a keypad, so they're usually res

      • I think on most headsets the PIN is preset and the number is in the manual or on a separate piece of paper. As for auto negotiation, on some phones you can turn off the PIN request.
  • by Adult film producer (866485) <van@i2pmail.org> on Friday June 03, 2005 @02:26PM (#12716348)
    this fucking depressing, can firmware updates fix these streams of bluetooth hacks? Or is the problem so close to the hardware that nothing but scrapping the device and building from ground-up fix it ?
    • Firmware updates? Heh, good luck to all of you stuck with non-flashable Nokia phones. Even the high end Nokia kit isn't firware-upgradable, which really sucks for those of us with early 3650 models that crash every few hours.
  • Time for WUSB...
  • Why, oh why ? (Score:1, Insightful)

    by Anonymous Coward
    Why doesn't the telecom industry learn ?

    Guys, what about hiring ONE competent cryptographer to design a wireless protocols ?
    • Why doesn't the telecom industry learn ? Guys, what about hiring ONE competent cryptographer to design a wireless protocols ?

      As with most paid employees, a cryptographer's competence decreases as his job security increases.

      It's only a hacker who has nothing legitimately to gain that would find an exploit like this. Unless he's a crazy researcher who put his life on hold to find some obscure flaw with hyperthreading processors.

      • Re:Why, oh why ? (Score:3, Insightful)

        by fuzzybunny (112938)
        Nope, most security professionals want to fix bugs. There will always be enough holes in software to make our lives difficult.

        Bluetooth in and of itself is a fairly decent protocol for what it was originally designed for (ca. 15m range personal networking). It encounters a lot of limitations in the capabilities of how it is implemented (i.e. static shared PINs, etc.)

        And you're mistaken about crazy hackers; I know of quite a few pretty top-end cryptographers still doing good research while employed as pe
      • Re:Why, oh why ? (Score:2, Informative)

        by cebailey (849614)
        Maybe I'm missing a beat here, but TFA says that the communications between Bluetooth devices ARE encrypted...it's simply a Bluetooth device's "heartbeat" that's unencrypted, and it allows for hacking.

        Now, if they maybe wanted to use more encryption so the key isn't as breakable, that would be an idea...but it would probably mean more expensive hardware, and longer PINs.

        My boss always says security and ease of use are on two opposite ends of a line, and with any system you have to put the 'x' somewher
  • While the last dowzin times I've paired devices HAVE been on the bus. I've noticed the auto generating pins are now 5 to 8 digits long.

    Further, it's extremely rare that I even SEE Another bluetooth device on the bos or train. While the phones may be popular, not a whole lotta people are using bluetooth, it seems.

    Additionally, the phones I've got default to a Bluetooth radio-off mode...ya can't see them unless you a) turn them on (v600) or b) are already paired (nokia 9820)

    Lastly, at 15 feet, there's not a large number of people around you that can pull this off (except that poindexter across the aisle with the laptop and dish antenna pointed at you)

    Now, if you're being shadowed at less than 20 feet by a guy with a BT headset, get worried...or turn off your phone...or ignore it, you've got a blue bajillion minutes anyway.
    • You can't hack a bluetooth easily unless you are within 15 feet of a person who also has bluetooth. You also can't catch a cold easily beyond that distance. Yet, my nose is running right now. The odds against me having a runny nose are mind boggling!

      Or, maybe not...

      • You can't hack a bluetooth easily unless you are within 15 feet of a person who also has bluetooth.

        Is that a fact? [tomsnetworking.com]
        • And there are exactly HOW many 'Toothers out there with a gun shaped antenna?

          The article says it can be done. The odds of it happening are _Vanishingly_ small.

          • And there are exactly HOW many 'Toothers out there with a gun shaped antenna?

            That information is classified. What's your security clearance, Citizen?

            The article says it can be done. The odds of it happening are _Vanishingly_ small.

            The odds of being struck by lightning are small, too, but sensible people still refrain from golfing in thunderstorms.
        • Yes, it is a fact. Spending a couple hundred dollars on parts and then requiring a diverse range of skills from welding to electronics assembly is by no stretch of the imagination considered "easily".
    • > Additionally, the phones I've got default to a Bluetooth radio-off mode...
      > ya can't see them unless you turn them on

      Wouldn't you have to leave it on (and vulnerable) in order to use one of those
      fancy wireless headsets tho?
      • Grandparent is a bit off on the v600. Bluetooth itself needs to be on to use headsets and so forth, but discovery is turned off by default (and can only be turned on for 60 seconds at a time, after which it turns back off).

        This means that under usual operating conditions, only devices that have previously paired with the phone can talk to it.

    • 15 to 20 feet? Try over a mile away with a BlueSniper Rifle [tomsnetworking.com].

      If that gets slashdotted, just UTFSE--bluetooth sniper hack gets you tons of relevant info.

      Yes, that's pretty visible on a bus, but what if I stand by the window of my 11-floor office and snipe the mindless drones walking the streets?

    • Heh, you forgot to mention that Ch 11 News in L.A. CA will do at least 15 FUD stories on how evil hackers will steal our phonebooks, identities, memories and souls through our Blue-Cheese phones while we sleep. They will run these stories on the same days they have some clown standing out in the drizzle to let us know of the "BIG STORM!" Oh, BTW, even though I've been known to scan for BT at Union Station I have NEVER sent anyone a picture of the goings on at the platforms - I SWEAR!
    • In the US, they may be uncommon. But in the UK, where we've (rightly, IMHO) banned the use of handheld mobile phones while driving, wireless headsets are very common indeed. And as far as I know, they're all bluetooth.
  • by Anonymous Coward


    Cracking the Bluetooth PIN [tau.ac.il]


    This paper describes the implementation of an attack on the Bluetooth security mechanism. Specifically, we describe a passive attack, in which an attacker can find the PIN used during the pairing process. We then describe the cracking speed we can achieve through three optimizations methods. Our fastest optimization employs an algebraic representation of a central cryptographic primitive (SAFER+) used in Bluetooth. Our results show that a 4-digit PIN can be cracked in less th
  • Finally... (Score:4, Funny)

    by Mattygfunk1 (596840) on Friday June 03, 2005 @02:28PM (#12716380)

    ...an excuse for my "adult" calls on my phone bills.

    __
    free funny videos [laughdaily.com]
  • by Anonymous Coward
    The more important issue here is bluetooth keyboards. Can people use this hack to get my password that I'm typing on a wireless keyboard. (Distance issues aside.)

    The article doesn't seem to say.
    • Can people use this hack to get my password that I'm typing on a wireless keyboard. (Distance issues aside.)

      Essentially, yes, although it's a bit complex. Basically, they can send out a packet that forces your keyboard to stop working. At this point you have to re-pair your keyboard, so you type in the PIN and re-pair it.

      Now, the PIN is never actually sent, but by capturing what *is* sent between your machine and your keyboard in setting up that secured connection, and then running a program to brute for
  • That is an extremely serious flaw. The device sends its key to anyone claiming to forgot theirs? That is a great design. Why wouldn't it only resend the key if it recognized the ID as something it already paired with?

    It's like your online bank site giving someone else your password, just because they said they forgot it.

    While I doubt this is a widespread serious issue with the small number of bluetooth devices now, it could be an issue on something like a train, where there are a lot of business co
    • The hacking device spoofs the ID of the known device, then says "whoopsie, I forgot our pin" causing the repairing, it said that in the article.
    • It's because the ID is spoofed. IE, it thinks it's sending it to someone they've already paired with, and because it's over the wire, the spoofing device can pick up the re-pairing.

    • Re:Serious Flaw (Score:3, Informative)

      by Mike Buddha (10734)
      The device sends its key to anyone claiming to forgot theirs? That is a great design. Why wouldn't it only resend the key if it recognized the ID as something it already paired with? \

      RTFA. The hackers device tells the other device that it forgot the key. The pairing is deleted. The user has to re-pair the devices if he wants to use them again. The hacker can listen to that second pairing and use the previously discovered techniques to get the key.

    • That is an extremely serious flaw. The device sends its key to anyone claiming to forgot theirs? That is a great design. Why wouldn't it only resend the key if it recognized the ID as something it already paired with?

      This has to be Microsoft's fault somehow.

    • Thanks guys. The serious flaw was with my reading comprehension. I must have missed the spoofing part somehow.

      It still isn't good, but at least it's not as bad as I thought.
    • Re:Serious Flaw (Score:3, Informative)

      by sPaKr (116314)
      It doesn't resend the key. The problem is that an unencrypted easily spoofable message can force the device to renegotiate a new key. This renegotiation is the vulnerable state. Really this just makes the orignal hack easier to preform in that it can happen when at any time instead of initial pairing of the two devices.
    • The device sends its key to anyone claiming to forgot theirs? [...] It's like your online bank site giving someone else your password, just because they said they forgot it.

      It's all a case of "be careful what you wish for..."

      Apparently a senior security researcher, in an effort to get an overzealous junior security researcher out of his hair, set him to the task of solving the problem of social engineering, and just to make sure he was occupied until nearly the end of time, told him he had to do it enti
  • by G4from128k (686170) on Friday June 03, 2005 @02:36PM (#12716448)
    Reading between the lines, it seems that the short nature of the PIN code is a key to the exploit. The attacker forces a re-pairing, listens to the re-pairing exchange, and then tries all possible PIN codes to determine which one is the right one. Because a 4-digit PIN has only 10,000 possibilities, it's easy to brute force it.

    A longer alphanumeric PIN might be a first step to making this exploit much less practical -- increasing the PIN search time from a fraction of a second to hours or days.

    This looks like another classic example of the fundemental tradeoff between usability and security.
    • You can't brute-force 10,000 combinations with a good hope of succeeding if you only get three tries. Even a 25 second wait after 3 incorrect PINs would make the attack last a full day.
      • You can't brute-force 10,000 combinations with a good hope of succeeding if you only get three tries. Even a 25 second wait after 3 incorrect PINs would make the attack last a full day.

        I could be wrong, but my understanding is that you record the negotiation process, during which the unknown PIN is exchanged. You can then go offline and figure out which PIN number would have resulted in the particular set of data exchanged during the negotation. Then, you can go back online, having bruted the correct PIN, and Bob's your uncle.
      • You can't brute-force 10,000 combinations with a good hope of succeeding if you only get three tries. Even a 25 second wait after 3 incorrect PINs would make the attack last a full day.

        Actually the "brute force" is not done by communication so the victim cannot stall the attack. The brute force attack is entirely computed in software by the attacker's PC. The attacker simulates all 10,000 combinations until he/she gets a match with what was sniffed during listening to the re-pairing processes. The att
      • You can't brute-force 10,000 combinations with a good hope of succeeding if you only get three tries. Even a 25 second wait after 3 incorrect PINs would make the attack last a full day.

        In order to get that kind of security you would need to change the pairing protocol to use EKE, SPEKE or similar protocol that which is resistant to offline attacks even with weak passwords. These algorithms are patented by Lucent and Phoenix Technologies.
  • by Zarhan (415465) on Friday June 03, 2005 @02:39PM (#12716483)
    Ok, before this the attacker could only attack when the target link was forming.

    With this, you can force them to re-form at will.

    Even so, you still need to bruteforce the PIN. The "PIN" is really a 16-byte field, and is not really limited to numeric (or even alphanumeric) characters.

    So what can be done:

    1) Start using long PIN codes (if your device is limited to numbers, at least use the maximum length)
    2) Software update that notifies user of the "forced re-pairing"
    3) Allow users to use PIN's beyond the numeric space or possibility to use some pre-shared secret keys.

    This affects those of you who use "1234" or similar keys for pairing process for convenience.
    • That's the combination to my luggage!
    • Most likely the devices shouldn't just notify the user of repairing, but prompt for the PIN then as well.

      Right now, it appears that:

      First pairing: Request PIN -> Have stored PIN -> Make that long internal code
      Subsequent pairing: Have stored PIN -> Make that long internal code

      If they just removed the optimisation of storing the PIN, then it would be more secure. Plus since there'd be no need to store it, then if you lost your phone no one could extract the PIN, which may well be the same as your
  • by Xaroth (67516) on Friday June 03, 2005 @02:41PM (#12716500) Homepage
    ...add one of these bad boys [tomsnetworking.com] and shake vigorously.

    Mmm... phreaky...
  • My guess would be... "Easy money baby."
  • In April 2004, UK-based Ollie Whitehouse, at that time working for security firm @Stake, showed that even Bluetooth devices in secure mode could be attacked.

    He must be a relative to the Whitehouse family in Cryptonomicon and The Baroque Trilogy - everyone in that family was supposed to be a hacker, after all. ;-)
  • they can work out the link key in just 0.06 seconds on a Pentium IV-enabled computer

    I wonder how long it would take with Pentium 4 disabled.


  • Time to get more Paris Hilton pics!
  • phone in my comment. But ... somehow ... my cell phone appears to be busy.
  • Ok, so I went and look at my bluetooth devices again (a Motorola cell phone and a Logitech keyboard/mouse) - in both cases, I don't see how this crack would actually work:

    - With the Logitech keyboard, you actually have to type in the PIN from the keyboard in order for it to pair.

    - The motorola must be told to pair specifically - so if it loses connection with a device, it won't automatically re-pair because I haven't made my phone pairable. To make the phone pairable requires a specific menu sequence and
    • Presumably Bluetooth car keys are not open to this attack? anyone know?
    • After having read the actual paper and not just TFA, I see how the attack works. It's done in several steps.
      • 1. The attacker sends an "oops I forgot our link key that we came up with way back whenever it was that we paired". The phone immediately stops talking with the device, because the device just reported "I can't be trusted."
      • 2. The attacker waits for the human victim to notice that his devices don't work. Perhaps his phone says "please reenter pair code with device 'logitech keyboard'", or mayb
  • ...even when security features are switched on.

    Why does everything come with security 'features'? Shouldn't everything be as secure as possible out of the box? If it was made inherently secure, it wouldn't need 'features'.
  • FTA: The first step requires the legitimate users to type the same secret, four-digit PIN into both devices.

    Pin length isn't fixed in bluetooth.
    It can be anything between 1 to 16 numbers.
    Sure it's easy to crack if you use one or two digit length,
    but with 8 digits or more, it will take much longer to crack using brute force.

    Besides, bluetooth always requires authorization before allowing network/dialup access from the modem device, even if it's already paired with the client machine.
    Annoying, but g
    • Nope, Bluetooth absolutely does not require the extra auth step. Without touching my phone, I can pick up my Tungsten and go online through my phone.

      You can, however, set up your phone so that this extra auth step is required. But this exposes you to exactly the vulnerability mentioned in the paper [tau.ac.il]:

      6 Countermeasures

      [ ... ]

      Most Bluetooth devices save the link key (Kab) in non-volatile memory for future use. This way, when the same Bluetooth devices wish to communicate again, they use the stored

  • The researchers who developed this new attack will be presenting their results in Seattle on Monday, June 6 at MobiSys 2005. Their paper can be viewed at http://www.eng.tau.ac.il/~yash/shaked-wool-mobisys 05/ [tau.ac.il]

    Mike

  • ...seriously. The giveaway is the 4 digit pin. Of course it's crackable. You don't even have to look at the specs to deduce that.
  • By looking at the timing results for their fastest algorithm (algebraic manipulation), it appears that adding a single PIN digit increases the calculation time 10-fold.

    Just by making the pin 8 digits, this crack would take over 12 minutes.

    And then there's this little tid-bit:

    "Note that the attack, as described, is only fully successful against PIN values of under 64 bits. If the PIN is longer, then with high probability there will be multiple PIN candidates, since the two SRES values only provide 64 bits
    • Re the 19 decimal digits thing: what % of PHBs do you think you'd be able to convince to use a _20+_ digit code? I believe that code has to be entered at each repairing?

      Also, the attack is trivially parallelisable (it's bruteforce, hence the exponential curve). Even without additional caching à la MD5, the amount of data describing the data is extremely small, and could easily be sent over the internet. 64 or 128 P4s aren't exactly hard to come by. Moreover, it seems like the researchers haven't used
    • And implementing something like that will just make it easier to hack in because people don't like to have to remember long passwords especially with weird requirements. They are very hard to remember and people just end up going with 111111111111111111 or some such thing.
  • this is really a flaw in the reconnection process. All they need to do is change the reconnection procedure--make it more complex (mathematically that is). For instance, during reconnect the sender's PIN must be encoded and resent (with the previously setup key stored on the sending device--which is likely not on the hackers device).

    With the relibility of bluetooth, peer reconnect is uncommon unless a guy w/a big antenna is sitting right next to you trying to disrupt your connection (as mentioned). It's n

  • I know Apple was the first to start shipping Bluetooth 2.0? What did they have to do with these security problems?

    Few people realize how Apple's responsible for many of the technologies that plague personal computers today. For example, the first computer virus recorded came out in 1982 on Apple hardware [wikipedia.org] and exploited flaws in Apple's early operating system. Apple also had a key role in the development of the MIME attachemnt protocol (via their NeXT subsidiary) that allowed malicious executable software t

    • Apple didn't invent Bluetooth 2.0. Also, how come Apple got their shit together and Microsoft didn't? Last time I check my Mac, it wasn't vulnerable to either any current virii or MIME-contained executables.

      And don't forget, Apple is also responsible for both 400Mb/s and 800Mb/s firewire, along with the best ZefoConf protocol there is, Rendezous/Bonjour. And made the 3.5" floppy disk standard....in fucking 1984. Original mac also shipped with a real sound processor and speaker, instead of that boop/bee
    • Uh-huh. So, the Apple ][ is the sole cause for Blaster, SoBig, Poza, and every single other virus out there? What about adware? Did Apple 'cause' that to happen too?

      And NeXT was never a subsidiary of Apple. NeXT broke away from Apple, started by Steve Jobs, and later bought to form Rhapsody and then completely re-written (but with the same ideals) to form OS X.

      And Bluetooth 2.0 is a standard. Apple doesn't make the standard-- they comply with the standard. Like I could make a web browser that whe

  • Sounds like we shoul start putting quote marks around the word "secure" whenver we talk about Bluetooth devices.
  • I'm about to buy a cell phone. I was looking at a couple blue-tooth phones, just to keep the cell phone viable for a longer period of time. Should I refrain?
  • So they are called "Cryptographers" now...

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