:::::Learn2hack:::::

Wireless networks broadcast their packets using radio frequency or optical wavelengths. A modern laptop computer can listen in. Worse, an attacker can manufacture new packets on the fly and persuade wireless stations to accept his packets as legitimate.
The step by step procerdure in wireless hacking can be explained with help of different topics as follows:-
1) Stations and Access Points :- A wireless network interface card (adapter) is a device, called a station, providing the network physical layer over a radio link to another station.
An access point (AP) is a station that provides frame distribution service to stations associated with it.
The AP itself is typically connected by wire to a LAN. Each AP has a 0 to 32 byte long Service Set Identifier (SSID) that is also commonly called a network name. The SSID is used to segment the airwaves for usage.
2) Channels :- The stations communicate with each other using radio frequencies between 2.4 GHz and 2.5 GHz. Neighboring channels are only 5 MHz apart. Two wireless networks using neighboring channels may interfere with each other.
3) Wired Equivalent Privacy (WEP) :- It is a shared-secret key encryption system used to encrypt packets transmitted between a station and an AP. The WEP algorithm is intended to protect wireless communication from eavesdropping. A secondary function of WEP is to prevent unauthorized access to a wireless network. WEP encrypts the payload of data packets. Management and control frames are always transmitted in the clear. WEP uses the RC4 encryption algorithm.
4) Wireless Network Sniffing :- Sniffing is eavesdropping on the network. A (packet) sniffer is a program that intercepts and decodes network traffic broadcast through a medium. It is easier to sniff wireless networks than wired ones. Sniffing can also help find the easy kill as in scanning for open access points that allow anyone to connect, or capturing the passwords used in a connection session that does not even use WEP, or in telnet, rlogin and ftp connections.
5 ) Passive Scanning :- Scanning is the act of sniffing by tuning to various radio channels of the devices. A passive network scanner instructs the wireless card to listen to each channel for a few messages. This does not reveal the presence of the scanner. An attacker can passively scan without transmitting at all.
6) Detection of SSID :- The attacker can discover the SSID of a network usually by passive scanning because the SSID occurs in the following frame types: Beacon, Probe Requests, Probe Responses, Association Requests, and Reassociation Requests. Recall that management frames are always in the clear, even when WEP is enabled.
When the above methods fail, SSID discovery is done by active scanning
7) Collecting the MAC Addresses :- The attacker gathers legitimate MAC addresses for use later in constructing spoofed frames. The source and destination MAC addresses are always in the clear in all the frames.
Collecting the Frames for Cracking WEP :- The goal of an attacker is to discover the WEP shared-secret key. The attacker sniffs a large number of frames An example of a WEP cracking tool is AirSnort ( http://airsnort.shmoo.com ).
9) Detection of the Sniffers :- Detecting the presence of a wireless sniffer, who remains radio-silent, through network security measures is virtually impossible. Once the attacker begins probing (i.e., by injecting packets), the presence and the coordinates of the wireless device can be detected.
10) Wireless Spoofing :- There are well-known attack techniques known as spoofing in both wired and wireless networks. The attacker constructs frames by filling selected fields that contain addresses or identifiers with legitimate looking but non-existent values, or with values that belong to others. The attacker would have collected these legitimate values through sniffing.
11) MAC Address Spoofing :- The attacker generally desires to be hidden. But the probing activity injects frames that are observable by system administrators. The attacker fills the Sender MAC Address field of the injected frames with a spoofed value so that his equipment is not identified.
12) IP spoofing :- Replacing the true IP address of the sender (or, in rare cases, the destination) with a different address is known as IP spoofing. This is a necessary operation in many attacks.
13) Frame Spoofing :- The attacker will inject frames that are valid but whose content is carefully spoofed.

14) Wireless Network Probing :- The attacker then sends artificially constructed packets to a target that trigger useful responses. This activity is known as probing or active scanning.

15) AP Weaknesses :- APs have weaknesses that are both due to design mistakes and user interfaces
16) Trojan AP :- An attacker sets up an AP so that the targeted station receives a stronger signal from it than what it receives from a legitimate AP.
17) Denial of Service :- A denial of service (DoS) occurs when a system is not providing services to authorized clients because of resource exhaustion by unauthorized clients. In wireless networks, DoS attacks are difficult to prevent, difficult to stop. An on-going attack and the victim and its clients may not even detect the attacks. The duration of such DoS may range from milliseconds to hours. A DoS attack against an individual station enables session hijacking.
18) Jamming the Air Waves :- A number of consumer appliances such as microwave ovens, baby monitors, and cordless phones operate on the unregulated 2.4GHz radio frequency. An attacker can unleash large amounts of noise using these devices and jam the airwaves so that the signal to noise drops so low, that the wireless LAN ceases to function.
19) War Driving :- Equipped with wireless devices and related tools, and driving around in a vehicle or parking at interesting places with a goal of discovering easy-to-get-into wireless networks is known as war driving. War-drivers (http://www.wardrive.net) define war driving as “The benign act of locating and logging wireless access points while in motion.” This benign act is of course useful to the attackers.
Regardless of the protocols, wireless networks will remain potentially insecure because an attacker can listen in without gaining physical access.

This is a tutorial of How you can make a Fake access point by using airsnarf in Backtrack.
As you know wireless hotspots are everywhere. A mobile user can obtain connectivity quickly and easily in a wide variety of public locations.  Some of these hotspots are free and some of them require a fee or subscription.  Either way, you will continue to see how being in a public Wi-Fi hotspot poses the greatest security risk you will find.

Stealing Wi-Fi Hotspot Subscription Credentials

A big issue a few years back had to do with dial-related fraud in Russia. Basically, usernames and passwords to dial accounts were being bought and sold on the black market and the owners of the stolen credentials were being hit with enormous usage charges.  In actuality, this still takes place.  With the onset of Public Wi-Fi locations, the threat of fraud and misuse has also moved to the stealing of wireless subscription credentials.

An easy and inexpensive method to steal wireless subscription credentials is by Access Point Phishing.  As it stands today, the only real methods a typical end-user has to determine if a wireless access point is valid is by recognizing the SSID (name of the wireless network) and ascertaining if the site has the look and feel of the real public Wi-Fi hotspot login page. Unfortunately for the end-user, both of these can be easily spoofed. Here’s how it’s done and no, you won’t have to carry a wireless access point around to do this.

Performing this technique requires two steps:

1. Setting up your computer to look like an actual Access Point broadcasting the appropriate SSID

1. Having the walled-garden, or login page that your computer will display look like the real login page of the provider whose signal you are broadcasting

It’s not hard to make your computer broadcast the SSID of your choice, in an attempt to get a person to connect to you instead of a valid Wi-Fi hotspot SSID.  The problem with the ‘easy way’ is that the potential victim sees that this is an Ad-Hoc network and most people these days know not to connect to these.  So, we employ the use of Airsnarf by the Schmoo Group to make this signal look like it’s coming from an Access Point.  Essentially, we will be turning the laptop into an Access Point.

The most difficult part of using Airsnarf and other HostAP (Host Access Point) reliant programs is finding a card that supports the HostAP drivers. Airsnarf consists of a number of configurable files that control how it operates.

Where to get Airsnarf

BackTrack  (BT) is a live CD based on Slax, hence Slackware, it is evolved from the widely adopted Whax and Auditor security distributions.

Slackware is one of the many Linux distribution, Slax is a linux live-distro version based on Slackware. BackTrack is a Penetration Testing oriented live-distro based on Slax.

BT has an intuitive layout, some tools are available in the menu and invoke automated scripts, most of the analysis tools are located either in the path or in the /pentest directory. It is possible to explore wireless tools under /pentest/wireless.

Airsnarf is located at /pentest/wireless/airsnarf-0.2

Using Airsnarf

dhcpd.src file can used to configure the DCHP settings of the access point created.
 


With Airnsnarf configured with default design settings, it will display a default login page that looks like the following. To make this attack really work, this login page needs to be modified to look just like a real Wi-Fi hotspot provider’s login.  Depending upon your HTML skills, you can either get real fancy or just stick to basics.



Once Airsnarf is configured and the customer Login page is created, the attack can be launched.  Any airport, coffee shop, or other public area where people utilize their laptops will work.  To launch the attack, activate Airsnarf by typing the ./airsnarf command.  Below is an example of what you’ll see when the attack is launched.
 


Airsnarf being launched and waiting for a connection

An end-user attempting to connect to the hotspot will see the SSID that was entered into the airsnarf.cfg file and use their computer to connect to that network.  Upon launching their browser, they will be prompted to enter their username and password.

Once the user enters their credentials and hits the Login button, their credentials have been compromised and can be used by the person with ill-intent.  This could be only the beginning, though.  Commonly, users will utilize the same username and password for many different accounts/websites.  Consequently, the username and password that were just grabbed may enable a hacker to access the user’s e-mail, online banking, etc.

This login page will take the username and password that is entered and will dump them into a file where it can be read.

Preventing Attack

There are basically two things to combating the previous hacks:

1. Taking measures to ensure a hotspot is valid
2. Protecting the machine against browser-based exploits