Chp 4 Wireless Networks

802.11a

this standard called for the use of OFDM. Because that would require hardware upgrades to existing equipment, this standard saw limited adoption for some time. (5 GHz) supports speeds up to 54 Mbps.

WPA Enterprise

Requires an authentication server using Remote Authentication Dial-In User Service and the 802.1x authentication protocol.

WLAN Structure

802.11 wireless

Code division multiple access (CDMA)

assigns a unique code to each call or transmission and spreads the data across the spectrum, allowing a call to make use of all frequencies.

Lightweight Extensible Authentication Protocol (LEAP)

is a Cisco proprietary alternative to TKIP for WPA. LEAP should be avoided when possible; use of EAP-TLS as an alternative is recommended, but if LEAP is used, a complex password is strongly recommended.

Wi-Fi Protected Access (WPA)

is designed to improve on WEP. First, it uses the Temporal Key Integrity Protocol (TKIP) for encryption, which generates a new key for each packet. Second, the integrity check used with WEP is able to detect any changes to the data. uses a message integrity check algorithm called Michael to verify the integrity of the packets.

Extensible Authentication Protocol (EAP)

is not a specific mechanism of authentication; rather it is an authentication framework. Effectively, allows for new authentication technologies to be compatible with existing wireless or point-to-point connection technologies.

Frequency Division Multiple Access (FDMA)

is one of the modulation techniques used in cellular wireless networks, that divides the frequency range into bands and assigns a band to each subscriber.

802.11

standard specified the use of either FHSS or DSSS and supported operations in the 2.4 GHz frequency range at speeds of 1 Mbps and 2 Mbps.

802.11n

standard uses several newer concepts to achieve up to 650 Mbps. It does this using channels that are 40 MHz wide, using multiple antennas that allow for up to four spatial streams at a time (a feature called multiple input, multiple output [MIMO]). It can be used in both the 2.4 GHz and 5.0 GHz

CCMP (Counter Mode with Cipher Block Chaining Message Authentication Code Protocol)

was created to replace WEP and TKIP/WPA. uses AES (Advanced Encryption Standard) with a 128-bit key. It is the preferred standard security protocol of 802.11

Supplicant

A software client running on the Wi-Fi workstation

Authentication Server (AS)

A server that contains an authentication database, usually a RADIUS server

WPA2 Personal

A modern security type for wireless networks that uses a pre-shared key for authentication. Uses AES instead of TKIP

Frequency Hopping Spread Spectrum (FHSS)

A spread-spectrum broadcasting method defined in the 802.11 standard that sends data on one frequency at a time, constantly shifting (or hopping) frequencies.

Direct Sequence Spread Spectrum (DSSS)

A spread-spectrum broadcasting method defined in the 802.11 standard that sends data out on different frequencies at the same time.

Orthogonal frequency division multiplexing (OFDM)

A spread-spectrum broadcasting method that combines the multiple frequencies of DSSS with FHSS's hopping capability.

WPA Personal

Also known as WPA-PSK or preshared key mode. Only wireless devices with the passphrase can join the network

WPA2 Enterprise

An authentication scheme for Wi-Fi networks that combines WPA2 with RADIUS. Uses AES instead of TKIP

802.11b

has support for FHSS and enabled an increase of speed to 11 Mbps. It was widely adopted because it both operates in the same frequency as 802.11 and is backward compatible with it and can coexist in the same WLAN.

Infrared

is a short-distance wireless process that uses light rather than radio waves, is used for short connections between devices that both have an infrared port. It operates up to 5 meters at speeds up to 4 Mbps and requires a direct line of sight between the devices.

Access point (AP or wireless AP)

is a wireless transmitter and receiver that hooks into the wired portion of the network and provides an access point to this network for wireless devices

Wired Equivalent Privacy (WEP)

was the first security measure used with 802.11. It can be used to both authenticate a device and encrypt the information between the AP and the device. The problem is that it implements the RC4 encryption algorithm in a way that allows a hacker to crack the encryption. With RC4 all devices share the same password in this way.

Antenna Placement and Power Levels

When deploying wireless networks, administrators should ensure that the WAPs are deployed in an appropriate location based on the results of the site survey. If a site survey shows that the signal extends well beyond the range that needs coverage, administrators should lower the power level of the WAP.

Site Surveys

A wireless site survey allows administrators to determine the wireless networks in range. Site surveys are used for many purposes. Often administrators perform a site survey prior to deploying a new wireless network to determine the standard and possible channels deployed. site surveys are used to determine if rogue access points have been deployed

Temporal Key Integrity Protocol (TKIP)

An encryption technology that replaces the Wired Equivalent Privacy (WEP) protocol.

MAC Filter

Another commonly discussed security measure that can be taken is to create a list of allowed MAC addresses on the AP. When this is done, only the devices with MAC addresses on the list can make a connection to the AP. Although on the surface this might seem like a good security measure, in fact a hacker can easily use a sniffer to learn the MAC addresses

Cellular or Mobile Wireless Techniques

Frequency division multiple access (FDMA) Code division multiple access (CDMA) Orthogonal frequency division multiple access (OFDMA) Global system for mobile communications (GSM) Massive multiple input multiple output (MIMO)

802.11 Techniques

Frequency hopping spread spectrum (FHSS) Direct sequence spread spectrum (DSSS) Orthogonal frequency division multiplexing (OFDM)

Infrastructure Mode Versus Ad Hoc Mode

In most cases a WLAN includes at least one AP. When an AP is present, the WLAN is operating in Infrastructure mode. In this mode, all transmissions between stations or devices go through the AP, and no direct communication between stations occurs. In Ad Hoc mode, there is no AP, and the stations or devices communicate directly with one another.

Wireless Antenna Types

Omnidirectional antennas can send data in all directions that are perpendicular to the line of the antenna. Directional antennas can send data in one primary direction. Yagi, parabolic, and backfire antennas are all directional antennas.

Authenticator

The wireless access point

Protected Extensible Authentication Protocol (PEAP)

encapsulates EAP methods within a TLS tunnel that provides authentication and potentially encryption. EAP is usually not encrypted. So PEAP can provide encryption for EAP methods

802.11g

has support for OFDM, which made it capable of 54 Mbps. This also operates in the 2.4 GHz frequency so it is backward compatible with both 802.11 and 802.11b. 5 GHz band is much less crowded than the 2.4 GHz band.

Service Set Identifier (SSID)

is a name or value assigned to identify the WLAN from other WLANs. The SSID either can be broadcast by the AP, as is done in a free mobile hot spot, or can be hidden. When it is hidden, a wireless station will have to be configured with a profile that includes the SSID to connect. Although some view hiding the SSID as a security measure, it is not an effective measure because hiding the SSID only removes one type of frame, the beacon frame, while it still exists in other frame types and can be easily learned by sniffing the wireless network.

802.1X

is a port access protocol that protects networks via authentication. It is used widely in wireless environments. When used, the access point opens a virtual port for communication. If authorization is unsuccessful, the virtual port is unavailable, and communication is blocked.

802.1x

is a port access protocol that protects networks via authentication. It is used widely in wireless environments. When used, the access point opens a virtual port for communication. If authorization is unsuccessful, the virtual port is unavailable, and communication is blocked.

Near Field Communication (NFC)

is a set of communication protocols that allow two electronic devices, one of which is usually a mobile device, to establish communication by bringing them within 2 inches of each other. can be provided with apps to read electronic tags or make payments

Massive multiple input multiple output (MIMO)

is a type of cell phone that is used in 5G implementations. 5G networks offer performance as high as 20 Gbps.

Bluetooth

is a wireless technology that is used to create personal area networks (PANs). These are simply short-range connections that are between devices and peripherals, such as headphones. Bluejacking is when an unsolicited message is sent to a Bluetooth-enabled device, often for the purpose of adding a business card to the victim's contact list. This can be prevented by placing the device in non-discoverable mode. Bluesnarfing is the unauthorized access to a device using the Bluetooth connection. In this case the attacker is trying to access information on the device rather than send messages to the device.

Zigbee

is an IEEE 802.15.4-based specification that is used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, is capable of up to 250 Kbps and operates in the 2.4 GHz band.

Wi-Fi Protected Access 3 (WPA3)

is being developed to address security issues with WPA2. includes several new features, including blocking authentication after a few failed login attempts (preventing brute-force attacks), simplifying device authentication, strengthening user security over open wireless networks, and implementing a 192-bit security suite for higher security environments.

Global system for mobile communications (GSM)

is the default global standard for mobile communication that contains a subscriber identity module (SIM) chip. These chips contain information about the subscriber and must be present in the phone for it to function.A danger is cell phone cloning, a process in which copies of the SIM chip are made, allowing another user to make calls as the original user.

Open System Authentication (OSA)

is the original default authentication used in 802.11. The authentication request contains only the station ID and authentication response. While it can be used with WEP, authentication management frames are sent in cleartext because WEP only encrypts data.

802.11ac

operates in the 5 GHz frequency. The most important feature of this standard is its multistation WLAN throughput of at least 1 Gbps and single-link throughput of 500 Mbps. Wireless access points have multiple antennas. 802.11ac is faster and more scalable than 802.11n. Advantages include Increased speed,Higher speeds over longer distances, Less interference, Increased number of clients supported by an access point,Extended battery life, Extended Wi-Fi coverage,Reduction of dead spots

Orthogonal frequency division multiple access (OFDMA)

takes FDMA a step further by subdividing the frequencies into subchannels. This is the technique required by 4G devices.

Wi-Fi Protected Access 2 (WPA2)

uses Counter Cipher Mode with Block Chaining Message Authentication Code Protocol (CCMP) based on Advanced Encryption Standard (AES), rather than TKIP. AES is a much stronger method and is required for Federal Information Processing Standards (FIPS)-compliant transmissions.