RE: V/Scan for Wireless LANs

From: Morgan, Andy (Andy.Morganat_private)
Date: Fri Jul 18 2003 - 09:51:26 PDT

  • Next message: David Nester: "RE: V/Scan for Wireless LANs"

    Ian,
     
    There are some tools that will work to try to find a WEP key but they require a lot of data and time.  They exploit known vulnerabilities in the WEP algorithm to find the keys.  However it could take as much as 500 meg of data.  I don't have the links handy.  Sorry.
     
    As far as brute forcing.  ok idea but not very doable.  to iterate through all cobinations would be 2^128 possibilities which gets you to about 3.4028236692093846346337460743177e+38 possible combinations.  If you assumed you could do 1 per second - which would be tough if you wait for DHCP to respond it would take you 10790283070806014188970529154990 years to get through all the combinations.  Thats a long time.  :)  If somebody could check my math that would be great.
     
    Thanks,
    afm
    
    	-----Original Message----- 
    	From: Ian Chilvers [mailto:Ian.Chilversat_private] 
    	Sent: Fri 7/18/2003 7:18 AM 
    	To: pen-testat_private 
    	Cc: 
    	Subject: V/Scan for Wireless LANs
    	
    	
    
    	Hi all
    	
    	We've been asked to perform a vulnerability assessment for a company that
    	has a Wireless LAN.  The W/LAN is running WEP with a random key generated,
    	rather than a dictionary word.
    	
    	Are there any tools out there that can brute force a WEP.
    	
    	Take this example.  A person parks the car in the car park and sniffs the
    	air waves with a product like NetStumbler.  He discovers the W/LAN but with
    	WEP.
    	
    	Is there a tool he can use to discover the WEP key (possible by brute force)
    	
    	If there isn't such a tool, how does this sound for an idea.
    	
    	Run a app that starts at binary 0's and counts upto 128bits of 1's
    	For each sequence listen to see if there are any sensible packets or even
    	send out a DHCP discover request to see if you get a reply.  This would then
    	possibly give you the WEP key.
    	
    	Any comments
    	
    	Ian....
    	
    	
    	
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