According to Wikipedia,
Wireless communication is the transfer of information without the use of wires. The distances involved may be short (a few meters as in television remote control) or long (thousands or millions of kilometers for radio communications). The term is often shortened to "wireless".
Generally a wireless network consists of three components. :
Detecting a wireless network can be pretty straight forward, if the wireless AP is not set as hidden. The following ways can be used to detect wireless networks.
The issues with the security of SSID led to the development and usage of wireless protocols and standards. The important standards are:
Two types of MITM:
Eavesdropping (mostly passive)
Manipulation (mostly active)
WEP uses secret keys to encrypt data. Both AP and the receiving stations must know the secret keys.
There are two kinds of WEP with keys of either 64bits or 128bits. The longer key gives a slightly higher level of security (but not as much as the larger number would imply). In fact the user keys are 40bits and 104bits long, the other 24bits in each case being taken up by a variable called the Initialization Vector (IV).
When a packet is to be sent it is encrypted using a combination of the IV and the secret key. The IV is different (in theory) for each packet, while the secret key is fixed. The resulting packet data looks like random data and therefore makes the original message unreadable to an outsider not knowing the key. The receiving station reverses the encryption process to retrieve the message in clear text.
IV values can be reused
In fact the standard does not specify that the value needs to change at all. Reusing keys is a major cryptographic weakness in any security system.
IV length is too short
24 bit keys allow for around 16.7 million possibilities. Sounds a lot, but on a busy network this number can be achieved in a few hours. 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.
Weak keys are susceptible to attack
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.
Master keys are used directly
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. WEP is seriously flawed in this respect.
Key Management and updating is poorly provided for
Administration of WEP keys is not well designed and difficult to do on large networks. Users tend to change keys very infrequently which gives a potential hacker lots of time to collect enough packets to launch an attack.
Message integrity checking is ineffective
WEP does have a message integrity check but hackers can change messages and recompute a new value to match. This makes the checking ineffective against tampering.
WPA is wireless security with greater protection than WEP. Most wireless networks should use either WEP or WPA. WPA-PSK is not much more difficult to configure than the older WEP, but is not available on some older products. All computers, access points, and wireless adapters must use the same type of security. See your user manuals for configuration instructions.
WPA operates in either WPA-PSK mode (aka Pre-Shared Key or WPA-Personal) or WPA-802.1x mode (aka RADIUS or WPA-Enterprise). In the Personal mode, a pre-shared key or passphrase is used for authentication. In the Enterprise mode, which is more difficult to configure, the 802.1 x RADIUS servers and an Extensible Authentication Protocol (EAP) are used for authentication. The enhanced WPA2 uses Advanced Encryption Standard (AES) instead of Temporal Key Integrity Protocol (TKIP) to provide stronger encryption mechanism.
Advantages of WPA
Disadvantages of WPA
WPA has significant advantages over WEP:
The EAP types supported by WPA-Enterprise are
For cracking WEP airmon-ng,airodump-ng and aircrack-ng package are used in linux based system.
WEP Cracking works in the following manner
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