Newsham exposed another vulnerability of WEP by demonstrating that the key generator used by many vendors is flawed for bit key generation. Using a typical laptop, he was able to crack a bit key is less than a minute. This weakness, exploited by commonly available tools such as AirSnort, WEPCrack and dweputils, has the ability to crack WEP keys by analyzing traffic from totally passive data captures.
If your network is consistently generating traffic at peak speeds, the WEP key 64 or bit can be cracked after capturing just a few hours of encrypted data. On a network with minimal activity, this attack could take days or even weeks to capture the requisite traffic.
Some packet injection techniques, however, have the ability to artificially flood the network with activity to reduce the amount of time it takes to collect enough packets for an FMS attack. On the other hand, keep in mind that vendors who include weak key avoidance techniques in their firmware which most do are not vulnerable to FMS attacks. So, be sure to update your firmware on a periodic basis! These issues don't make WEP useless, it just means that you have to be careful about how and when you use it.
If you aren't able to implement anything else such as WPA , and the only thing you have is WEP , then go ahead and use it. If you're in a network with minimal security requirements, WEP may be appropriate. I recommend using WEP and changing keys on a regular basis, if for no other reason, then because it identifies your network as private. Since the I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.
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Participation is voluntary. It is now recommended to use at least WPA, but how much longer until that can be cracked by everyday computers? His management of iTech News has led him to work with many brands on writing technology focus articles. Discover Section's community-generated pool of resources from the next generation of engineers. The simple, flexible deployment options your customers expect with the low overhead your team craves. For Infrastructure Providers.
Simple, centralized, intelligent management of distributed compute locations on massive scale. What is WEP? The plaintext message is run through an integrity check algorithm and the Integrity Check Value ICV is appended to the end of the original plaintext message.
Last the cipher text is then added with the IV in plaintext and then transmitted. The decryption process is the reverse of the encryption process.
Reuse is then unavoidable. Some manufacturers use random keys. This is not the best way to ensure against reuse. A better solution is to start with a key and increment by one for each subsequent key. Unfortunately many devices revert to the same value at start up and then follow the same sequence providing lots of duplicate values for hackers to work on. Certain keys value combinations, Weak IVs, do not produce sufficiently random data for the first few bytes.
This is the basis of the highly publicized attacks on WEP and the reason that keys can be discovered. Manufacturers often deliberately disallow Weak IV values.
This is good in that it reduces the chances of a hacker capturing weak keys, but also has the effect of reducing the already limited key possibilities further, increasing the chance of reuse of keys. From a cryptographic point of view using master keys directly is not at all recommended. Master keys should only be used to generate other temporary keys.
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