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WiFi - Wireless Networks

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  • WiFi - Wireless Networks

    WiFi is widely in use today both because it is easy to implement and in some cases using a wired network is just not practical. Some common business use wireless as part of the infrastructure and some, such as airports, hotels, coffee shops, libraries and others use it as a service for customers. When wireless is in place to work as an extension to an existing wired network, either software-based Access Points (SAP) or Hardware-based Access Points (HAP) can be used. A HAP is considered a hardware appliance such as a physical router or access point and a SAP is a system such as a computer that is connected to the existing wired network which also has an enabled WiFi card shared amongst other WiFi enabled devices. In some cases several APs are in place to allow connected users to roam from location to location seamlessly without losing connectivity. In come cases a LAN-to-LAN wireless connection is in use, not to connect users to the network but to connect two separate networks. Such solutions could be between two buildings separated by a street where the cost of using a wired connection may be expensive or impossible. A 3G or 4G hot spot is also included in the category of wireless networks.
    The risk associated with using wireless has increased compared to traditional wired networks. Attackers have found wireless networks much easier to attack than wired networks.

    Even though wireless technologies provide users with convenience and flexibility, it has some important drawbacks.

    These include the following
    • There is a dramatic decrease in available bandwidth than with wired networks because of the amount of connected devices and the limitations of the technology itself.
    • You must invest in new equipment and an extended infrastructure.
    • Interference is an issue because many other electronic devices operate on similar frequencies as WiFi.
    • The range of a wireless network can be less than advertised and can be affected by numerous things such as doorbells, microwaves, baby monitors, the wireless next door, humidity etc.
    • Terrain can slow down or impede wireless signals.

    Some advantages are
    • You do not have to deal with wires
    • You can connect in places where it would be impossible to run wires

    A wireless network uses radio waves to transmit data and this is part of the physical layer in the OSI model. Wireless networks fall into the range of technologies covered in the IEEE 802.11 standard and has been adopted by everything from laptops and smart phones to game consoles and cameras. WiFi itself was build from the 802.11 specification which defines most details, including how to manage a connection through techniques such as Direct Sequence Spread Spectrum (DSSS), Frequency-Hopping Spread Spectrum (FHSS), infrared (IR), and Orthogonal Frequency-Division Multiplexing (OFDM). Wireless uses the ISM (Industrial, Scientific, and Medical) band which is an unlicensed band of frequencies, meaning they are not regulated like your favorite radio station is.

    Remember when assessing wireless connections that technologies such as Bluetooth and WiMAX (802.16) may also be included in the attack surface.

    Does range matter? Yes, of course! As with any fairly secure system it is a balance of a system being user-friendly and secure. A wireless infrastructure with a long range gives the user a well-working system but may leak wireless signals far beyond the business property. This will increase the risk of war driving, war walking or an attacker in a van just out side the premises attempting to penetrate the infrastructure. Even though laws are in place to limit the transmit power of a WiFi radio on the frequencies used for wireless, networks has gotten faster and more widespread and they use wider frequency bands than before.
    Some special types of antennas may give the attacker the ability to listen in on wireless traffic from great distances. These antennas are unidirectional or directional antennas and have an incredible range. Often omni-directional antennas are used inside organizations that covers everything around the access point. Not just 360 degrees around the AP but if the environment will allow it, also the floor below or the floor above the AP. The signal does not have to be very strong for an attacker to sniff the traffic as long as the access point emanates radio energy in all directions.
    Certified Security Geek