WEP was previously known to be insecure. Some time later, it was shown that this attack can be applied to WEP and the secret key can be recovered from about 4,, to 6,, captured data packets.
In a hacker named KoReK improved the attack: the complexity of recovering a bit secret key was reduced to , to 2,, captured packets. In , Andreas Klein presented another analysis of the RC4 stream cipher.
Klein showed that there are more correlations between the RC4 keystream and the key than the ones found by Fluhrer, Mantin, and Shamir which can additionally be used to break WEP in WEP like usage modes.
Using active techniques like deauth and ARP re-injection, 40, packets can be captured in less than one minute under good condition. The actual computation takes about 3 seconds and 3 MB main memory on a Pentium-M 1. The same attack can be used for 40 bit keys too with an even higher success probability. We believe that WEP should not be used anymore in sensitive environments.
Find an aircrack-ptw How To here. Please note aircrack-ptw should be used together with the aircrack-ng toolsuite. One could of course argue that stupidity should be made punishable. If you have an open or badly locked down AP yo are asking for it and regarding the amount of pc magazine having spend tutorial on how-to lock down you wireless setup you could argue for neglect on part of the AP owner. Although it is questionable to mooch off of other peoples wireless internet, its not illegal where I live well not yet at least.
I think using it for my basic surfing is fine although I wont be using anything like torrents which could call the persons service into question or bog down their internet connection. This software is very difficult to install.
It can be checked by executing the iwconfig command. Next step is finding available wireless networks, and choosing your target:. To capture data into a file, we use the airodump-ng tool again, with some additional switches to target a specific AP and channel.
Most importantly, you should restrict monitoring to a single channel to speed up data collection, otherwise the wireless card has to alternate between all channels. Assuming our wireless card is mon0, and we want to capture packets on channel 6 into a text file called data:. Running airodump-ng on a single channel targeting a specific access point Notes: You typically need between 20, and 40, data packets to successfully recover a WEP key.
One can also use the "--ivs" switch with the airodump-ng command to capture only IVs, instead of whole packets, reducing the required disk space. However, this switch can only be used if targeting a WEP network, and renders some types of attacks useless. Increase Traffic aireplay-ng - optional step for WEP cracking. An active network can usually be penetrated within a few minutes. However, slow networks can take hours, even days to collect enough data for recovering the WEP key.
The aireplay-ng command should be executed in a separate terminal window, concurrent to airodump-ng. It requires a compatible network card and driver that allows for injection mode.
You may also want to read the information available -here-. To see all available replay attacks, type just: aireplay-ng. WEP cracking is a simple process, only requiring collection of enough data to then extract the key and connect to the network. You can crack the WEP key while capturing data. In fact, aircrack-ng will re-attempt cracking the key after every packets. Usually, between 20k and 40k packets are needed to successfully crack a WEP key. It may sometimes work with as few as 10, packets with short keys.
What this means is, you need to wait until a wireless client associates with the network or deassociate an already connected client so they automatically reconnect. All that needs to be captured is the initial "four-way-handshake" association between the access point and a client. This can be obtained using the same technique as with WEP in step 3 above, using airodump-ng.
You may also try to deauthenticate an associated client to speed up this process of capturing a handshake, using:. Note the last two numbers in brackets [ ACKs] show the number of acknowledgements received from the client NIC first number and the AP second number. It is important to have some number greater than zero in both.
If the first number is zero, that indicates that you're too far from the associated client to be able to send deauth packets to it, you may want to try adding a reflector to your antenna even a simple manilla folder with aluminum foil stapled to it works as a reflector to increase range and concentrate the signal significantly , or use a larger antenna.
Simple antenna reflector using aluminum foil stapled to a manilla folder can concentrate the signal and increase range significantly. For best results, you'll have to place the antenna exactly in the middle and change direction as necessary. Of course there are better reflectors out there, a parabolic reflector would offer even higher gain, for example. See related links below for some wordlist links. You can, then execute the following command in a linux terminal window assuming both the dictionary file and captured data file are in the same directory :.
After that, an offline dictionary attack on that handshake takes much longer, and will only succeed with weak passphrases and good dictionary files. My record time was less than a minute on an all-caps character passphrase using common words with less than 11, tested keys! A modern laptop can process over 10 Million possible keys in less than 3 hours.
This prevents the statistical key-grabbing techniques that broke WEP, and makes hash precomputation more dificult because the specific SSID needs to be added as salt for the hash. There are some tools like coWPAtty that can use precomputed hash files to speed up dictionary attacks. Those hash files can be very effective sicne they're much less CPU intensive and therefore faster , but quite big in size.
The external PIN exchange mechanism is susceptible to brute-force attacks that allow for bypassing wireless security in a relatively short time few hours. The only remedy is to turn off WPS, or use an updated firmware that specifically addresses this issue. To launch an attack:. Set your network adapter in monitor mode as described above, using:. Alternatively, you can put your network card in monitor mode using: airmon-ng start wlan0 this will produce an alternate adapter name for the virtual monitor mode adapter, usually mon0.
Before using Reaver to initiate a brute-force WPS attack, you may want to check which access points in the area have WPS enabled and are vulnerable to the attack. You can identify them using the "wash" Reaver command as follows:.
Run Reaver it only requires two inputs: the interface to use, and the MAC address of the target. There are a number of other parameters that one can explore to further tweak the attack that are usually not required, such as changing the delay between PIN attempts, setting the tool to pause when the access point stops responding, responding to the access point to clear out failed attempts, etc.
The above example adds "-vv" to turn on full verbose mode, you can use "-v" instead for fewer messages. Reaver has a number of other switches check with --help , for example " -c11" will manually set it to use only channel 11, " --no-nacks" may help with some APs. Spoof client MAC address if needed.
Reaver supports MAC spoofing with the --mac option, however, for it to work you will have to change the MAC address of your card's physical interface wlan0 first, before you specify the reaver option to the virtual monitor interface usually mon0. To spoof the MAC address:. Note that some routers may lock you out for a few minutes if they detect excessive failed WPS PIN attempts, in such cases it may take over 24 hours.
Common pins are , , , etc. Assuming we have our operating system ready and our driver updated to allow packet capturing and packet injection, we have to choose the right application that does the math when finally cracking WEP. We have chosen the aircrack-ng suite. Although Ubuntu comes with the aircrack preinstalled, it is advised to get the latest version:. Once we have our computer ready for WEP cracking, we can proceed to the fun part which is described on the next page: How to crack WEP encryption wifi security.
Efforts to crack WEP encryption have been around and even publicly discussed since the inception Setting up and configuring WPA security depends on the scale of your network and the robustness of s We have asked thi Allow shared folders to be published is a policy related to allowing network users to share resources on your network.
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