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WEP Broken Even Worse

Posted by kdawson on Tue Apr 03, 2007 04:43 PM
from the give-me-a-minute dept.
Security Wireless Networking Hardware IT
collin.m writes in with news of results out of Darmstadt. Erik Tews and others there have demonstrated how to recover a 104-bit WEP key in under a minute, requiring the capture of fewer than 10% the number of packets the previous best method called for. The paper is here (PDF). Quoting: "We were able to extend Klein's attack and optimize it for usage against WEP. Using our version, it is possible to recover a 104 bit WEP key with probability 50% using just 40,000 captured packets... for 85,000 data packets [the success probability is] about 95%... 40,000 packets can be captured in less than one minute under good condition. The actual computation takes about 3 seconds and 3 MB main memory on a Pentium-M 1.7 GHz..."
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  • Can ARC4 be used properly at all? (Score:5, Interesting)

    by Myria (562655) on Tuesday April 03 2007, @04:48PM (#18595335)
    Can ARC4 be used securely at all? Or are WEP's failings its own fault?

    On a somewhat related note, I'm annoyed that wireless encryption was implemented in hardware. Nintendo DS's wireless is worthless to me since the encryption system can't be upgraded.

    • Re:Can ARC4 be used properly at all? (Score:5, Insightful)

      by Lehk228 (705449) on Tuesday April 03 2007, @05:03PM (#18595607) Journal
      disable wireless security and implement real security, such as a RADIUS login. then set up a firewall rule to allow unauthenticated devices to access nintendo's servers

      • disable wireless security and implement real security, such as a RADIUS login. then set up a firewall rule to allow unauthenticated devices to access nintendo's servers

        Login authentication does not prevent a man in the middle attack of the breakin sort.

        You need end to end encryption, including encrypted login and certificate verification with secure exchange made pre-connection to provide security over a wireless link.

        Just another reason why if it's not a PDA or a tablet, you should be using a wire. You can get 100' or more of CAT5E for the price of a 802.11G access point, and an 8 port 10/100 FDX switch with port autonegotiation (auto-crossover, too) is about $20. Good jacks will run you $5 per end. Patch cables are a buck and longer cables are just a few bucks.

        • Dragging 300' of cable throughout and around your house to use your laptop anywhere you want: priceless.

            • Re:Can ARC4 be used properly at all? (Score:4, Interesting)

              by Scoth (879800) on Tuesday April 03 2007, @09:14PM (#18598513)
              My problem is I tend to be a wanderer. I might be surfing the web in my computer room, boot up the laptop and go sit on the couch for awhile and surf while watching the news or something, then go into the bedroom and play a few webgames while my fiancee works on homework, then maybe go sit on the back deck in the evening and get a little extra work done. Short of really long cables, or lots of plugging/unplugging, going wired isn't really practical. Of course, I guess that's what WPA and other better wireless security setups are for, although ideally I'd set up my DD-WRT with the wireless on a different segment. I'll get to it sooner or later. I've mostly made do with frequently rotated and never repeated wep keys, although that was going on the assumption of needing to capture tons of packets to crack it. This new thing throws that a bit out of whack...

        • Re:Can ARC4 be used properly at all? (Score:4, Insightful)

          by zippthorne (748122) on Tuesday April 03 2007, @05:16PM (#18595821) Journal
          It's not the wire that's expensive, it's the holes. In fact, those aren't even the expensive bit. It's the properly out-of-the way and invisible that's expensive.

          • Re:Can ARC4 be used properly at all? (Score:5, Insightful)

            by Belial6 (794905) on Tuesday April 03 2007, @05:20PM (#18595893) Homepage
            I agree with you. That is why I really annoys me that in this day and age, builders are still not putting conduit in walls during construction. I understand a 20 year old house not having conduit in the walls. I can even understand a 10 year old house not having conduit, but any house built in the last 5 years should have conduit to every room. We already know that whatever is in the walls today will be inadequate in another 10 years.

            • Conduit (Score:3, Insightful)

              by xquercus (801916)
              The only real conduit one needs in a house are a crawlspace and an attic.

            • Re: (Score:3, Informative)

              by failedlogic (627314)
              About 5 years ago when I worked for sales at a cable company, a mid to large size home builder told me every house he was building would have Cat-5 in every room of the house with a wall jack. He didn't care if the room was the laundry, the basement, the attic (ok, attic I'm exaggerating) but he was serious about it. I think he was one of the first builders in my city to do this. I remember his story and then a few years later the larger builders ensued with similar practices. He did similar pre-wiring with

              • Re:Can ARC4 be used properly at all? (Score:5, Insightful)

                by Belial6 (794905) on Tuesday April 03 2007, @09:26PM (#18598601) Homepage
                That is a perfect example of what I consider a bad builder. One that is putting in things that are designed to make people THINK they are getting quality, when they really are not. I could care less about Cat-5 and coax, if you just put in a conduit. That builder has already created a situation where the wiring is out dated. Gigabit wants Cat-6. If he had put in conduit, every one of his houses could be rewired by the homeowner with very little fuss. But since the builder didn't care if the house was maintainable, he just slapped in some wire, and sprinted that he did it as a bullet point on the sales sheet. Part of the problem though is that the buyers ooohhh and ahhhh about the cat-5, and don't even think about what they are going to do in a few years.

        • Re:Can ARC4 be used properly at all? (Score:5, Insightful)

          by thealsir (927362) on Wednesday April 04 2007, @12:23AM (#18599751) Homepage
          Common Slashdot Format(TM)

          1. Story posted about $SECURITY_PROTOCOL being broken on $BROKEN_DATE at $SEVERITY
          2. Comments ensue recommending ridiculously complex/impractical solutions (in typical slashdot lore) getting modded up
          3. Comments ensue about how ridiculous and complex those impractical solutions are, getting modded down/up on a 50/50 basis
          4. Actual common-to-do, easy to implement solutions, like the WPA2 in linksys routers, are not discussed or modded
          5. Extreme architecture biases/overall naivete about NO security implementation being completely secure is prevalent in a lot of comments
          6. Sometimes, people come in to right these fallacies in the free market way, by posting.

          Put short, wires are not a solution, no encryption protocol is flawless, the risks/rewards of wireless should be known and the technology should be used accordingly. But improvements in protocol and advancements in technology, especially relatively easy to implement ones, should be emphasized.

          • Re: (Score:3, Interesting)

            by MS-06FZ (832329)

            So, for instance, the laptops of the house would all use WPA and the NDS would use WEP?

            That wouldn't really increase the overall security of the network. If somebody wanted to break in, he'd just crack the WEP encryption..

            I am aware of that flaw. However, I'm attempting to make the best of a bad situation - a perfect solution is not possible.

            The idea is that by having the NDS and only the NDS use WEP, the opportunities for sniffing WEP packets will be limited to those times when someone's accessing the network with an NDS - as opposed to when one of our unwired computers is on (and presumably doing some net activity, either in the foreground or background), which is pretty much all the time. So if someone wanted to break

    • The problems with WEP have nothing to do with RC4. The problem is that the initialization vectors end up being reused because they are only 24 bits. Reusing IVs is a major no-no when dealing with a stream cipher. And to compound that, the implementation allows for a 50% chance to use the same IV after only 5000 packets. (see wikipedia)

      RC4 is still just as secure as it was before these WEP attacks.

      • Re:Can ARC4 be used properly at all? (Score:5, Insightful)

        by kakos (610660) * on Tuesday April 03 2007, @05:58PM (#18596467)
        Get a clue. The weakness in WEP has everything to do with a vulnerability in RC4 (specifically this one [drizzle.com]). The vulnerability is due to the fact that there is a weakness in RC4's key scheduling algorithm that allows an attacker to obtain the whole key from only a very few bits that just happen to be in the first 24-bits of the key. Since the IV does repeat, it is easy to obtain packets with the weak key bits. However, if WEP did not use RC4, that vulnerability wouldn't be there and you couldn't break WEP using that attack.

    • Re:Can ARC4 be used properly at all? (Score:5, Informative)

      by linuxmop (37039) on Tuesday April 03 2007, @05:22PM (#18595917)
      Wireless encryption is (often) implemented in hardware because encryption is expensive to perform. This is especially true on embedded platforms like the DS.

      However, you can apparently upgrade your DS to support WPA with a hacked firmware [geekboy.ca]. It's not clear from the page, but I am fairly sure that it only supports TKIP encryption and not AES since, like WEP, TKIP uses RC4 so does not require a hardware upgrade. It does, however, solve the initialization vector problems of WEP that another poster mentioned; as far as I know, TKIP has not been broken.

      Moral? If you're still using WEP, update your drivers and firmware and you may be able to get TKIP WPA and get those pesky neighbors off of your connection.

  • Back in the courtroom (Score:5, Funny)

    by Nom du Keyboard (633989) on Tuesday April 03 2007, @04:53PM (#18595423)
    Your Honor, I was using WEP on my Linksys when the RIAA claimed their agents, Media Sentry, claimed that my IP address was involved in illegal filesharing. I was taking the best precautions my poor little 802.11b router can handle. Allow me to now introduce a paper here explaining how my system can be broken by the average desktop computer in less than a minute.

    Case Dismissed!

    • Re:Back in the courtroom (Score:4, Insightful)

      by TheGratefulNet (143330) on Tuesday April 03 2007, @05:07PM (#18595683)
      its modded as funny BUT its a VERY valid defense, I would think (ianal).

      there is significant doubt as to who the user of a wireless lan really is.

      in fact, it now makes sense to DOWNGRADE wireless AP's due to this...

      (and then just run ssh on top of it, for sessions that truly need privacy).

      • Re: (Score:3, Interesting)

        by dissy (172727)
        Shame about the file fragments (or whole files) they'll find on your harddrive.. which the court will compell you to produce to a forensic expert. You're better off planting a worm infection on your computer.. then claim you were part of a botnet.

        Totally valid point. One of the main reasons you should stay under the radar and not get a finger pointed at you if at all possible.

        While excuses such as 'someone was on my wireless' are totally valid, the court will indeed check your systems, and once they find t

  • Does this still depend on weak IVs? (Score:4, Interesting)

    by Zarhan (415465) on Tuesday April 03 2007, @04:57PM (#18595493)
    For some reason I can't get the paper to load, but anyway, does this still depend on weak initialization vectors?

    I know that the original attack did depend on that, and most software and basestations have since been configured to avoid those weak IVs. I know that some stuff (like Nokia's basestations) are still weak agains the original attack (at least when tested with Kismet), however, against Cisco Aironets and almost any newer hardware I haven't been able to see this weakness in action when trying out if it really works...

    (Terabeam uses the term "WEPPlus" about this - see http://www.terabeam.com/solutions/whitepapers/wep- plus.php [terabeam.com] )

    Anyway, if this is just extension of the original attack, then it still requires those weak IVs to exist.

    Or is it something completely new?

    • Re:Does this still depend on weak IVs? (Score:5, Informative)

      by tbo (35008) on Tuesday April 03 2007, @05:06PM (#18595649) Journal
      For some reason I can't get the paper to load, but anyway, does this still depend on weak initialization vectors?

      According to the article, the attack does not require weak IVs. They haven't actually tested against WEPplus, but expect the attack to still work against it. In other words, WEP in all its forms is now nothing more than an electronic "No trespassing sign" and 3-foot fence.

  • What about 64 and 128 bit? (Score:4, Interesting)

    by andy55 (743992) on Tuesday April 03 2007, @05:05PM (#18595639) Homepage
    This may be a dumb question, but why does TFA only refer to 40 and 104 bit WEP when the more common variants seem to be 64 and 128 bits?

    • Re:What about 64 and 128 bit? (Score:5, Informative)

      by !ramirez (106823) on Tuesday April 03 2007, @05:07PM (#18595677)
      Because there's a 24-bit IV, or initialization vector, that is not strictly considered part of the keyspace.

    • Re: (Score:3, Informative)

      by Galaga88 (148206) *
      Not a stupid question, a good question.

      WEP uses a 24 bit initialization vector, and the rest is left for the actual key. So 40 bit = 64 bit - 24 bit IV. Same for 128 = 104. People just use the terms interchangably (for better or for worse).

  • No problem for me (Score:5, Funny)

    by NotFamous (827147) on Tuesday April 03 2007, @05:19PM (#18595853) Homepage Journal
    I use 56-bit WEP and I've never had.... ATTN: YOU HAVE WON THE IRISH LOTTERY PLEASE respons immediately to... ...so I don't see why it is a big deal?

  • Today on duh news. (Score:5, Funny)

    by kinglink (195330) on Tuesday April 03 2007, @05:22PM (#18595925)
    WEP insecure! Coming up at 6PM Bill Gates still really really rich.

  • 10 minutes, 1 minute... no big deal (Score:3, Interesting)

    by geekinaseat (1029684) on Tuesday April 03 2007, @06:07PM (#18596559) Homepage

    This isn't really news. It's pretty smart that they have managed to crack WEP with so few IVs (it usually takes about 200,000 for 64bit and just under a million for 128bit) but in reality this doesn't change (or expose) WEPs inherent vuneribilities at all, for example I am currently doing my dissertation on wireless security and in tests WEP64 on average can be cracked in about 3 minutes and WEP128 in about 10 minutes so getting this down to a minute doesn't really change the fact that a hacker could capture enough packets simply by hanging around and drinking a coffee using the "old" tools.

    An interesting sidenote is that the amount of time a hacker needs to be near a target WLAN for WPA-PSK is measured in seconds making it much more insecure if it has a weak passphrase than WEP is even now with crack times under a minute.

    Please if you want a secure home wireless network choose WPA-PSK and make the passphrase as long and as abstract as possible, nothing else is safe -and if you have the cash... buy a radius server

    • Re: (Score:3, Interesting)

      by Rick17JJ (744063)

      For my computers at home, I used the "Perfect Password Generator" that is on the grc.com web page to generate the longest most random possible WPA password. Each time I visit that web page a different a password is generated. I then placed the password on a USB key and transfered the password to both of my computers and the wireless router. I then cut and pasted the password instead of trying to type the huge password. For the extra paranoid, slicing and dicing and mixing up the long password that is ge

  • The most obvoius solution. (Score:3, Insightful)

    by Randseed (132501) on Tuesday April 03 2007, @06:10PM (#18596599)
    The most obvious solution is to have each machine that connects over wireless use a VPN. Everything coming in over anything other than the VPN is discarded.

    Since this is Slashdot, I request a community service: Come up with a script/whatever where this is simple.

  • Broken Even Worse?! (Score:5, Funny)

    by Seumas (6865) on Tuesday April 03 2007, @07:21PM (#18597467)
    Slashdot editors suck at grammar. Obviously, the words they were looking for was supposed to be more brokener.

    • Re:Who even still users WEP? (Score:5, Insightful)

      by Knara (9377) on Tuesday April 03 2007, @04:54PM (#18595431)
      No. Even a cursory glance at your laptop next time you are in a commercial parking lot will tell you that (or at an apartment complex).

      • Re:Who even still users WEP? (Score:5, Interesting)

        by Technician (215283) on Tuesday April 03 2007, @06:23PM (#18596777)
        No. Even a cursory glance at your laptop next time you are in a commercial parking lot will tell you that (or at an apartment complex).

        No. We use some prety antique hardware (laptop with embedded 11b no WPA). We are fairly remote so the number of potential attackers is pretty slim. To discourage them, DHCP is truned on. The DHCP range is blocked from the gateway by access control. To get a leachable connection, you will need to spoof a MAC address, use a fixed IP address, and hope we are not online at the moment. A conflict will be noticed.

        We don't need a hack proof wireless. We just need to be more difficult than our neighbors.

      • Re:Who even still users WEP? (Score:4, Interesting)

        by nutshell42 (557890) on Tuesday April 03 2007, @06:25PM (#18596797) Journal
        Well, from a legal POV the plausible deniability an unsecured WLAN offers is quite tempting.

        As long as you secure your computers and data (and if you're not charged by the GB), it's really useful to be able to tell the judge that it was teH h4X0rZz when the RIAA rings at your door.

        • Re:Who even still users WEP? (Score:4, Insightful)

          by JWW (79176) on Tuesday April 03 2007, @06:19PM (#18596713)
          Hell, out of 5 wireless networks I can "see" from my house, two have no encryption on whatsoever.

          I mean, no matter how bad WEP is, you'll never be able to hack into a WEP network as fast as you can an open one.

          It may be where I live, but around town there are open networks virtually EVERYWHERE.

    • Re:Who even still users WEP? (Score:5, Insightful)

      by ukatoton (999756) on Tuesday April 03 2007, @04:57PM (#18595487)
      2 words: Legacy Hardware I have 2 computers in my house with cards that don't support WPA. If I were to set my router to run with WPA, then my sister would not be able to connect to the network. If i told her the security implications, she wouldn't understand nor care. Upgrading the network would mean me footing the bill for new wireless cards unless I can convince my dad that there is a real reason to upgrade to better security. However, this is unlikely.

    • Re:Who even still users WEP? (Score:4, Informative)

      by Southpaw018 (793465) * on Tuesday April 03 2007, @05:04PM (#18595619) Journal
      Unfortunately, Nintendo has outright refused to support WPA on the DS. Those who use the DS online regularly must either fall back to WPA or resort to completely unsecured communication. Or change their router's settings every single time they want to play online.

      Nintendo's response to this is, last I checked, "well, disable WEP and then turn off your computer," which is obviously ridiculous.

    • Re: (Score:3, Informative)

      by Zadaz (950521)
      I live in downtown San Francisco. If I put my laptop in my kitchen window I can pick up 46 wireless networks.

      2 of them are WPA-PSK (including mine)
      12 of the are unsecured.
      The rest are WEP.

      7 of the WEP encrypted ones are the DSL router/wireless access point that AT&T hands out. As far as I can tell this piece of hardware can't be configured in any way, can't even change your WEP key.

      • Re: (Score:3, Insightful)

        by jrumney (197329)
        All my pieces of wifi equipment but one support WPA-PSK, but it only takes one piece of equipment to tie me to WEP.

        • So.. your answer is "people who don't upgrade." Not to sound discriminatory, but I'm pretty sure he wasn't including you in the question, much the way when I say "Who doesn't run a firewall?" I'm not including people who still use C64s. Talk to us again when all your hardware supports WPA, but you still use WEP anyway.

          Well, that was an incredibly arrogant response from someone who refuses to examine reality.

          How many environments are you familiar with in which everything is always upgraded all at the same time, in which all of the hardware works the first time, and in which you never become dependent on a legacy product for any length of time?

          Here in the really real world, we often have reasons to utilize legacy hardware. What if I've got one of those $1500 bar code scanner boxes and it doesn't support WPA and there's no upgrade to provide it? Am I going to spend $1600 for this year's model with two more buttons and WPA support? Or am I going to keep using this device as long as I think I can get away with it? What if I don't have budget to buy a replacement? What if it's not even my decision?

          Like I said, here in the real world, we often have to use suboptimal equipment. And I assure you that huge numbers of corporations, including those amongst the fortune whatever, are still using wifi gear with no WPA support on a daily basis.

        • Re: (Score:3, Insightful)

          by zippthorne (748122)
          It's faster than his Internet connection, which apparently is a cable modem. No need to go significantly faster than the main bottleneck. Especially if the LAN is mostly used to share the WAN anyway.

      • Corporate Greed (Score:5, Informative)

        by Lead Butthead (321013) on Tuesday April 03 2007, @05:47PM (#18596351)
        My understanding is that it should be easy enough to implement WPA on older (.11a/b) hardware, but companies much rather sell end user new hardware (.11g etc.) than spending development time to upgrade old hardware (that does not generate additional revenue.) This is evident in that Apple's old AirPort (.11b) does support WPA but other venders' (that would include YOU, Linksys) old .11a/b products do not.
      • WPA "cracks" are all just brute force, which you could also do with WEP and any other encryption algorithm. It just takes fucking forever (assuming the user chose a key that was more than just a dictionary word). These WEP attacks are actually flaws in the design of the system which allow you to crack a key many times faster than brute force.

        Rainbow tables, dictionaries, and the like are all just variations on brute force. They accelerate the process, but either way you're not actually breaking the encryption but instead using a crapload of processor power to try one key after another until you hit the right one.

        Saying WPA is insecure because there is a brute force tool for it is like saying the a lock is insecure because I could go and start trying combinations. 1-1-1....1-1-2....1-1-3.........
      • Wireless Total Price: $80
        CAT5 Total Price*: $393

        Having your network compromised and your identity stolen: Priceless

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