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.
This might be a good time to move over to WPA. If WEP can be cracked that quickly, you won’t feel safe using it. It’s noted further that the actual computation was completed in under 3 seconds on a 1.7GHz laptop.
Source: Slashdot