"Freedom always comes at a price" | ||
--Samir Datt |
Today, people desire to be free from the restraining and restricting wires. Always connected and always online, the growth of this desire has fueled the proliferation of wireless networks. Who doesn't have Wi-Fi at home or at their place of work? Our phones are connected using Wi-Fi, our tablets are connected over Wi-Fi and with the advent of the Internet of Things (IoT), even our household devices are connected over Wi-Fi or will be in the future!
However, the freedom of a wireless existence comes at a price. Wireless networks broadcast a signal that is open to the air. With no physical limitations except those of range, this signal is open to interception and interpretation by the bad guys.
In the previous chapters, we saw how information travels in packets over the network physical layer. In wireless LAN networks, the data packets are broadcast wirelessly over the air. The receiving device reads the packet header, identifies the packets that are meant for it, and collects just those while discarding the rest. This means that any network device that is on the wireless network can receive the data packets meant for somebody else if it is set up and configured to do so.
To enhance your understanding of the wireless world and upgrade the ability to investigate it, we will cover the following topics in this chapter:
At the Institute of Electrical and Electronics Engineers (IEEE), a working group was set up to create specifications for wireless local area networks (WLANs). This slowly evolved into a family of specifications known as the IEEE 802.11 specifications for wireless LANs.
The Ethernet protocol forms the foundation of all the 802.11 specifications.
As investigators who are getting ready to explore the forensics of wireless networks, it is important to develop an understanding of the underlying technology. The 802.11 specifications allow us to gain an insight into data speeds, spectrums, encoding, and so on.
These standards are downloadable and available free of charge from the IEEE website at http://standards.ieee.org/about/get/802/802.11.html.
In a nutshell, the 802.11 specifications are a set of media access control (MAC) and physical layer (PHY) specifications that govern communications in wireless LANs in the 2.4, 3.6. 6, and 60 GHz frequency bands.
The 802.11 specifications were first released in 1997. These consisted of a series of half-duplex, over-the-air modulation techniques that use the same basic protocol. Since then, they have undergone considerable changes and a number of specifications have been released. Amendments have also been added to the specifications in order to address further evolution. In fact, all wireless network products adhere to one or the other 802.11 specifications and amendments.
There are several specifications in the 802.11 family, as shown in the following:
All the major 802.11 specifications can be represented in an easy-to-understand table, as shown in the following:
802.11 Standard |
Year of Release |
Frequency Band GHz |
Modulation |
Data Transmission Rate (Mbits/sec) |
---|---|---|---|---|
802.11 |
1997 |
2.4 GHz |
DSSS/FHSS |
2 Mbit/s |
802.11a |
1999 |
5 GHz |
OFDM |
54 Mbit/s |
802.11 ac |
2013 |
5 GHz |
OFDM |
6.93 Gbit/s |
802.11ad |
2012 |
60 GHz |
SC-OFDM |
6.76 Gbit/s |
802.11b |
1999 |
2.4 GHz |
DSSS |
11 Mbit/s |
802.11g |
2003 |
2.4 GHz |
DSSS/OFDM |
54 Mbit/s |
802.11n |
2009 |
2.4/5 GHz |
OFDM |
600 Mbit/s |
Full form of abbreviations used in the table are as follows:
Now that we have developed an understanding of what is going on at the MAC and physical layers, let's move on to understanding a bit about wireless protection and security.
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