Nowadays The most common ones are:. DSSS is also a protocol used to reduce noise interference by combining the signal with a higher data rate bit sequence commonly called a chipping code which separates the data up in to a logical sequence and attaches a form of CRC to the packet before transmitting.
Unlike the original It transmits data in the 2. Is sometimes called Wi-Fi. It uses OFDM like However unlike A point worth noting here is if you have an If you do want to get in to WEP cracking it is well worth your while investing in a dual band card. I will talk about Wireless Adaptors more later on. Well cracking WEP is fairly easy to understand if you have followed what I explained above. As I stated before WEP very kindly transmits the IV in clear, so if we can run a mathematical equation against it we can find and decipher the RC4 stream that encrypted the whole packet in the first place.
Remember the AP or the client has this key to use when decrypting the packet and is what we must find by running a complicated algorithm against the encrypted packet. If we run a statistical anyalisis against the IV to try and decrypt the packet, we can find the key used at the begining of the process.
When you try to decrypt them, every time you crack a piece of the algorithm the corresponding plain text part of the packet is revealed, once the whole packet is decrypted you know the algorithm used to encrypt that particular packet — A crude way of describing it but as simple as I can make it. This XOR can then be used to infer data about the contents of the data packets.
Once all the plain text of a data packet is known, it will also been known for all data packets using the same IV. So before any transmission occurs WEP combines the keystream with the payload using an XOR process, which produces ciphertext data that has been encrypted. WEP includes the IV in clear in the first few bytes of the frame.
XOR is a mathematical algorithm which I am not even going to attempt to explain. There is a copy of cygwin1. The peek. You will get a peek driver not found message if you dont do this. You also need to go to Wild Packets to pick up a new driver for your card. I have found that the most common cause of stress when trying to crack WEP is incompatible hardware. The Airopeek driver from Wild Packets is not compatible with all types of hardware.
There is a list of supported adaptors and the relevant driver you need to use on the web site. This card works with Whax, Auditor and BackTrack pretty much straight out of the box. It is my preferred Wireless Adaptor and has not let me down yet.
Most cards that are Atheros based will have the Atheros logo on the side of the box, use one of these if possible. Connexant cards are also a complete waste of time which I found out the hardway so please do not even think about buying one of these if you want to crack WEP. Aircrack-ng Cygwin1. Now we need to install the driver you have downloaded. The peek driver will not let you use your Wireless Adaptor in the conventional way. The Peek driver puts your Adaptor in to a promiscuous mode to allow it to sniff all Windows may display a prompt warning you that the driver is not digitally signed, if ths happens click continue anyway.
Cracking WEP is by now means a skilful thing to do, as all the hard work was done by Chris Devine who is the excellent coder of Aircrack, all we need to do is collect the data and start the program.
If you have questions about Aircrack a good place to post them is on the Netstumbler Linux Forums as I believe the author checks here quite often. To be fair, we also would like to draw your attention to our five-part wireless security tutorial which helps you to make your network more secure. It depends on your initial knowledge and equipment. Cracking WEP itself is relatively easy and can take as little as 5 minutes.
The problem is often with setting up your computer, so that it does what it needs to do for WEP cracking. In most cases, you need to upgrade your wireless driver which you first need to find somewhere.
Finding out how to set up your computer to crack WEP can take weeks! The driver that comes with the adapter from Intel does not support adapter promiscuous monitor mode and packet injecting and needs to be updated. There are many tools and approaches available on the web for WEP cracking, and one can get easily lost and confused when reading all the information provided on discussion forums OmniPeek, WinAirCrack, airmon, aircrack, Kismet, mac driver, ipwraw driver, ilw, etc.
The first question that needs to be answered is which platform to use. Some have had success with Windows XP. This is for one major reason.
Are you new to Linux? Do not worry. Just follow prompts in the Ubuntu installation process. After installing Ubuntu, get all system updates in the system application manager. Your wireless card driver needs to support two important functionalities:. Packet injection is a computer networking term which refers to sending a packet on a network into an already established connection.
Monitor mode allows packets to be captured without having to associate with an access point or ad-hoc network first.
We have had good luck with the ipwraw driver from aircrack. The lines of code below install the driver together with other two packages to your Ubuntu installation. Now you should have an upgraded driver available. 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. Reaver attempts known default pins first. Reaver comilation requires libpcap pcap-devel and sq3-devel sqlite3-dev installed, or you will get a "pcap library not found" error.
Here are some points to consider:. Is your adapter properly set in monitor mode? Does the adapter driver support injection is aireplay-ng working?
Do you have a good signal to the AP? Do you see associated clients for WPA handshake capture? As demonstrated above, WEP cracking has become increasingly easier over the years, and what used to take hundreds of thousands packets and days of capturing data can be accomplished today within 15 minutes with a mere 20k data frames.
Simply put, cracking WEP is trivial. However, weak passphrases are vulnerable to dictionary attacks. An extensive list of vulnerable devices is available here: google docs spreadsheet. Username: Password: forgot password? Home » Articles » Security. Yes, the aircrack suite will work under Vista as well. All commands need to be ran under "elevated command prompt" admininstrator priviledges , or you need to have UAC User Account Control turned off.
The only potential problem under Windows is that fewer network adapters have compatible drivers that support monitor mode. Do I need to install any drivers?
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