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WEP Is Dead, Haven't You Heard?

Wi-Fi Security: Cracking WPA With CPUs, GPUs, And The Cloud
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Wired Equivalent Privacy (WEP) was the first security algorithm used by wireless networks to restrict access. It was originally introduced in 1999 as part of the 802.11 standard. However, it has long been considered to be a "broken" algorithm, and was effectively replaced by Wi-Fi Protected Access (WPA).

Recovering a WEP key out in the wild.Recovering a WEP key out in the wild.

If you're still using WEP on an older wireless router, try not to feel too safe. The Wi-Fi Alliance abandoned WEP in 2003 because it's very easy to crack. With $20 and some basic technical know-how, a neighbor can procure your WEP password in about 10 minutes using publicly-available tools. It really is time to upgrade to at least WPA.

The process of breaking a WEP password can vary, but we've seen it done enough times that there's little reason to detail this bit of deviousness here on Tom's Hardware. Think of us like AMC's Breaking Bad. We're not here to show you how to cook meth. But our story hinges on the process. An enthusiast using WEP should know how easy it is to circumvent, and we did it so that you don't have to learn the hard way. To give you an idea of what's involved, we used Cain & Abel, Aircracking-ng, and an AirPcap Nx adapter to find a nearby network's WEP key in about five minutes. The length of the key doesn't affect recovery time, either.

Connecting to the cracked network after six minutes of effort.Connecting to the cracked network after six minutes of effort.

The fundamental problem is that it's incredibly easy to eavesdrop on a WEP network and sniff out the information needed to crack the RC4 cipher backing the protocol. Even if there aren't enough packets traveling between the router and clients inside the network, it's possible to send packets in such a way to simulate reply packets, which then can be used to find the key. It's even possible to forcibly boot users off a router in order to generate packets with authentication information. Scary stuff; avoid it at all costs if security truly matters to you.

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  • 6 Hide
    fstrthnu , August 15, 2011 4:50 AM
    Well it's good to see that WPA(2) is still going to hold out as a reliable security measure for years to come.
  • 9 Hide
    runswindows95 , August 15, 2011 4:52 AM
    The 12 pack of Newcastles works for me! Give that to me, and I will set you up on my wifi! Free beer for free wifi!
  • 9 Hide
    Soma42 , August 15, 2011 4:59 AM
    I think I'm going to go change my password right now...
  • 3 Hide
    Pyree , August 15, 2011 5:10 AM
    runswindows95The 12 pack of Newcastles works for me! Give that to me, and I will set you up on my wifi! Free beer for free wifi!


    Then either beer at your place is really expensive or internet is really cheap. Need 6x12 pack for me.
  • 14 Hide
    compton , August 15, 2011 8:01 AM
    Thanks for another article that obviously took a lot of work to put together. The last couple of articles on WiFi and archive cracking were all excellent reads, and this is a welcome addition.
  • 4 Hide
    Anonymous , August 15, 2011 9:38 AM
    What about the permutations of the words?
    i.e ape can be written:
    ape, Ape, aPe, apE, APe, aPE, ApE, APE.
    Thats 2^3=8 permutations. Add a number after and you get (2^3)*(10^1)=80 permutations.
    You can write PasswordPassword in 2^16=65536 ways.
    How about using a long sentence as a password?
    i.e MyCatIsSuperCuteAndCuddly, thats 2^25 permutations :) 
  • 7 Hide
    molo9000 , August 15, 2011 9:57 AM
    Any word on MAC address filtering?
    Can you scan for the MAC addresses? It's probably easy to get and fake MAC adresses, or it would have been mentioned.


    *scans networks*
    12 networks here,
    1 still using WEP
    10 allowing WPA with TKIP
    only 1 using WPA2 with AES only (my network)
  • 5 Hide
    agnickolov , August 15, 2011 10:50 AM
    Considering my WPA password is over 20 characters long I should be safe for the foreseeable future...
  • 10 Hide
    aaron88_7 , August 15, 2011 11:05 AM
  • 2 Hide
    ojas , August 15, 2011 12:24 PM
    Interesting article, i see that my fortress is safe :) 
  • 3 Hide
    dickcheney , August 15, 2011 1:40 PM
    molo9000Any word on MAC address filtering?Can you scan for the MAC addresses? It's probably easy to get and fake MAC adresses, or it would have been mentioned.*scans networks*12 networks here,1 still using WEP10 allowing WPA with TKIPonly 1 using WPA2 with AES only (my network)


    Same over here. I have a guest though, its a bit weaker than my main network. The guest is a 20 alphanumerical character long WPA2 AES-256bit. My main is 40 character long... Guess I went a bit overboard.
  • 0 Hide
    gokanis , August 15, 2011 1:43 PM
    aaron88_7"12345, that's amazing, I've got the same combination on my luggage!"Still makes me laugh every time!


    One of the best lines in the movie...
  • 1 Hide
    fausto , August 15, 2011 1:46 PM
    i better check on security when i get home
  • 3 Hide
    banthracis , August 15, 2011 1:50 PM
    molo9000Any word on MAC address filtering?Can you scan for the MAC addresses? It's probably easy to get and fake MAC adresses, or it would have been mentioned.*scans networks*12 networks here,1 still using WEP10 allowing WPA with TKIPonly 1 using WPA2 with AES only (my network)


    MAC address filtering is a joke, especially if the network actively broadcasts its SSID. Simple reason, MAC address and IP info is not even encrypted when sent over the air. So, wait for legit user to connect, grab his MAC, spoof MAC address and enjoy.
  • 6 Hide
    acku , August 15, 2011 2:11 PM
    Quote:
    "Why? Because an entire word is functionally the same as a single letter, like "a." So searching for "thematrix" is treated the same as "12" in a brute-force attack."

    This is an extremely wrong conclusion. Extremely wrong.



    If you truly understand programming, then you know that my statement is a comparison of dictionary vs. brute-force attacks. In a dictionary attack, you provide a wordlist, which is used to make unique combination. For a brute-force attack, each letter is randomly selected and joined together in a string. The length of a password has no bearing on the number of KDFs. I suggest that you read Ivan Golubev's blog post and hit up the BackTrack forums if you need help understanding why this is the case.

    Quote:
    "Next Big Bang" do you known what moore's law is? that "All (Printable) ASCII characters" 12 character password will be cracked in your lifetime, possibly with the cpu power of your cell phone.
    in 1982 we had spectrum zx with a z80 cpu running @3.5mhz. now I've an intel E7-8870 with 10cores running @E7-8870. not to mention like you demonstrated that gpu's are far more powerful cracking passwords. Also you can use other programs, pyrit is not the best for cracking with gpu's. Also you can use rainbow tables.
    Your assumption that a WPA2 with 12 characters is safe forever is very wrong and missleading and dangerous. It's the same assumptions that made people believe WEP was ok to use forever. now we can crack wep under 1 minute.


    RISC? That better be distributed if we're going to walk down that path. And as I've explained time and time again, rainbow tables are not valid for this type of attack. I purposely explained why under "Understanding WPA/WPA2."

    Second, I'm not sure what you're using but Pyrit is considered the standard by which other brute-force crackers are measured for WPA/WPA2. It's what's used at DEFCON. Our version has some optimizations, but again, it you go to any of the major security conferences, you'll find that it's what people use.

    Third, WEP is can be broken with relative ease because it's not a brute-force attack that renders it ineffective. It's a related key attack. Any nondirect attack leverages weaknesses in order to compromise a system. That's a different ballpark. We're dealing with cracking at the lowest common denominator.

    Quote:
    What about the permutations of the words?
    i.e ape can be written:
    ape, Ape, aPe, apE, APe, aPE, ApE, APE.
    Thats 2^3=8 permutations. Add a number after and you get (2^3)*(10^1)=80 permutations.
    You can write PasswordPassword in 2^16=65536 ways.
    How about using a long sentence as a password?
    i.e MyCatIsSuperCuteAndCuddly, thats 2^25 permutations :) 


    Permutations of words don't count in a dictionary based attack. I mean com'on. :)  Let's be reasonable. You're either paranoid at this point or too smart. Though, I'd argue that caps on the first letter is easily defeatable.

    Cheers,
    Andrew Ku
    TomsHardware.com
  • 2 Hide
    custodian-1 , August 15, 2011 2:28 PM
    All through history people have tried to lock things if someone locks it someone else will figure how to unlock it. It may me mathematically impossible but it's not the only way. Someone will have to know the password and we are fallible.
  • 0 Hide
    WyomingKnott , August 15, 2011 4:03 PM
    Quote:
    or amateur script kiddies testing their meddle.

    I try to avoid picking on grammar or word errors, since it seems that many of these articles are translated from German. But this is a beauty.

    The phrase is usually "testing their mettle," which the dictionary on Yahoo! defines as "Courage and fortitude; spirit." The usual error on this phrase is the substitution of the word "metal" by spell checkers, dictation software, or people who don't know the origin of the phrase.

    But since these kiddies do indeed "meddle" with out networks, our data, and our lives, the substitution works elegantly.
  • -2 Hide
    jamie_1318 , August 15, 2011 4:17 PM
    Man sucks for all you people who live close enough to there neighbor to worry about their password being hacked. My nearest neighbor is more than 200m away, and than I live in a brick house, so it barely goes out the windows. It would be pretty obvious if some dude was standing outside my house accessing my files.
  • 3 Hide
    djridonkulus , August 15, 2011 4:17 PM
    Why don't they limit the number of authentication attempts like you said in the article like banks? Wouldn't that kill all attempts at brute force hacking?
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