WiFi security (was wifi access from laptop to starbucks wifi)

Joel Rees joel.rees at gmail.com
Wed Jun 23 08:24:22 UTC 2010


On Jun 23, 2010, at 11:14 AM, JD wrote:

>
>
> On 06/22/2010 07:27 PM, Darr was caught red-handed while writing::
>> On Tuesday, 22 June, 2010 @22:00 zulu, JD scribed:
>>
>>
>>> WPA2-PSK + AES : I thought it is not possible for inter-customer
>>> traffic to figure out the keys because once the connection is
>>> established,
>>> keys change dynamically per the protocol. Perhaps a an expert on the
>>> WPA2-PSK protocl can shed some light on this.
>>>
>> The unsecure part is, if left to their own devices people tend
>> to choose weak passwords. It really is that simple.
>>
>> If you choose a password that is a dictionary word or the name
>> of one of your kids/friends/pets, or a phone number, or a simple
>> sequence on the keyboard like 123456, 1234qwer, qwertyuiop,
>> et cetera, then AES can be 'cracked' using the dictionary method.
>>
>> If you choose a passphrase like 1a!B2 at Cd3#4$efGH(56) it's
>> virtually uncrackable, Especially since there's a 1-minute xmit
>> timeout enforced when there have been 2 wrong PW tries in
>> 30 seconds. Even if they could make 3 guesses per second it
>> should take a couple hundred centuries to crack that passphrase.
>>
>>
> Even so, that does not mean you can decrypt another user's traffic,
> because you will n ot be able to find out the keys that were  
> exchanged just
> before the client transmitted a packet, regardless of how
> weak the passphrase is when using AES.
> All clients will be using same passphrase anyhow (assuming we
> are still talking about using a public wifi hotspot, or
> even a workplace shared wifi router/gateway, which is set
> to accept only WPA2-PSK and AES encryption - no two
> clients will be in lock-step conversation with the gateway
> such that they exchange same keys with the gateway.
> So, inter-client traffic (which means that someone has
> some software on his/her machine, and has set his/her
> interface in promiscuous mode and is trapping packets from
> some particulat IP address. Good luck trying to decrypt them
> The Japanese team of scientists could not do it.

Don't know where you're coming from, guy, but don't get too  
confident. There are groups where AES and all the current wireless  
standards are considered broken, not from weak passwords.

(Not sure why you're talking about the Japanese scientists, either.)
  


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