Guide to Operating
System Security
Chapter 8
Wireless Security
Objectives
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Explain wireless networking and why it is used
Describe IEEE 802.11 radio wave networking
Explain Bluetooth networking
Describe attacks on wireless networks
Discuss wireless security measures
Configure security for wireless interfaces in
workstation operating systems
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Introduction to Wireless
Networking
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Enables communications where a wired
network is impractical
Reduces installation costs
Provides “anywhere” access
Enables easier small and home office
networking
Enables data access to fit the application
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Attacks on Wireless Networks
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Many opportunities, particularly through
sniffer software
Difficult or impossible to detect
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Wireless Network Support
Organizations
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Wireless LAN Association (WLANA)
WINLAB
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Why Use a Wireless Network
Instead of a Wired Network?
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A wired network can be difficult or impossible
to install in some situations
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Radio Wave Technologies
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Network applications use high frequencies
measured in hertz
Line-of-sight transmission
Spread spectrum technology
Popular technologies
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IEEE 802.11 standard
Bluetooth
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Radio Wave Technologies
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Radio Wave Technologies
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Advantages
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Relatively inexpensive
Easy to install
Provide anywhere access
Offer an alternative for hard-to-cable areas
Disadvantages
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Do not have speeds to match 100Mbps
communications
Frequencies may experience interference
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IEEE 802.11 Radio Wave
Networking (Continued)
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Advantages in terms of compatibility and
reliability
Devices are not proprietary
Encompasses fixed and mobile stations
Recognizes indoor and outdoor
communications
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IEEE 802.11 Radio Wave
Networking (Continued)
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Kinds of communication
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Discrete units (asynchronous)
Governed by time restrictions
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How IEEE 802.11 Wireless
Networks Function
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Components
Access methods
Handling of data errors
Transmission speeds
Authentication
Topologies
Multiple-cell wireless LANs
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Wireless Components
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Wireless NIC (WNIC)
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Functions as a transmitter/receiver (transceiver)
Access point
Antennas
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Directional antenna
Omnidirectional antenna
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Directional Antenna
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Omnidirectional Antenna
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Wireless Networking Access
Methods
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Priority-based access
Carrier Sense Multiple Access with Collision
Avoidance (CSMA/CA)
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Handling Data Errors
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Automatic repeat request (ARQ) characteristic
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Helps reduce communication errors created by
sources of interference
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Transmission Speeds
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Infrared Wireless Networking
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802.11R standard
Can be broadcast in a single direction or in all
directions
Transmits in range of 100 GHz to 1000 THz
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Infrared Wireless Networking
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Security factors
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Difficult to intercept without someone knowing
Not susceptible to interference from RFI and EMI
Disadvantages (but also make it more secure)
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Data transmission rates only reach up to 16 Mbps
(directional) and can be less than 1 Mbps
(omnidirectional)
Does not go through walls
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Diffused Infrared Wireless
Communication
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Using Authentication to
Disconnect
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Prevents two communicating stations from
being inadvertently disconnected by a
nonauthorized station
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802.11 Network Topologies
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Independent basic service set (IBSS) topology
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Consists of two or more wireless stations that can
be in communication
Does not use an access point
Extended service set (ESS) topology
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Uses one or more access points to provide a larger
service area than an IBSS topology
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IBSS Wireless Topology
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ESS Wireless Topology
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Multiple-Cell Wireless LANs
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ESS wireless topology that employs two or
more access points
Inter-Access Point Protocol (IAPP)
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Roaming protocol that enables a mobile station to
move from one cell to another without losing
connection
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Bluetooth Radio Wave
Networking
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Uses frequency hopping in the 2.4-GHz band
designated by FCC for unlicensed ISM
transmissions
Uses time-division duplexing (TDD) for
packet transmissions
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Anatomy of Attacks on Wireless
Networks
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Antenna
Wireless network interface card
GPS
War-driving software
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Rogue Access Point
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Wireless access point installed without
knowledge of network administrator
Not configured to have security
Provides an attacker with an unsecured
entryway to packet communications
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Attacks Through Long-Range
Antennas
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Increases reach of a signal
Enables network to be monitored from a
greater distance without being observed
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Man-in-the-Middle Attacks
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Interception of a message meant for a different
computer
Attacker operates between two communicating
computers in order to:
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Listen in on communications
Modify communications
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Pitfalls of Wireless
Communications
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Inherently not secure because they are
transported over radio waves
Considerations
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Avoid wireless communications for extremely
sensitive information
Configure tightest security available
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Wireless Security Measures
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Open system authentication
Shared key authentication
Wired Equivalent Privacy (WEP)
Service set identifier (SSID)
802.1x security
802.1i security
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Open System Authentication
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Two stations can authenticate each other
Provides little security, only mutual agreement
to authenticate
Default form of authentication in 802.11
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Shared Key Authentication
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Uses symmetrical encryption
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Same key for both encryption and decryption
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Wired Equivalent Privacy (WEP)
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Same encryption key is used at both stations
that are communicating
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Wired Equivalent Privacy (WEP)
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Service Set Identifier (SSID)
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Identification value:
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typically up to 32 characters in length
defines a logical network for all devices that
belong to it
Each device is configured to have same SSID
Typically used in ESS, but not IBSS
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802.1x Security
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Port-based form of authentication
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Does not include encryption
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Uncontrolled port
Controlled port
can be set up to work with EAP and its evolving
versions (EAP-TTLS and PEAP)
Use different computers for authentication
server and authenticator
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802.1i Security
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Builds on 802.1x standard
Implements Temporal Key Integrity Protocol
(TKIP) for creating random encryption keys
from one master key
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Configuring Security for
Wireless Interfaces
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Windows 2000/XP Professional
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Red Hat Linux 9.x
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Support use of WNICs
Supports use of WNICs (installed through
GNOME desktop Network Device Control tool)
Mac OS X
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Built-in compatibility for AirPort WNICs and base
stations (access points)
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Windows 2000 Professional
Wireless Security Techniques
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Open system
authentication
Shared key
authentication
WEP (40-bit and
104-bit keys)
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SSID
802.1x
EAP
Authentication
through RADIUS
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Windows XP Professional
Wireless Security Techniques
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Open system
authentication
Shared key
authentication
WEP (40-bit and
104-bit keys)
Guide to Operating System Security
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SSID
802.1x
EAP and EAP-TLS
PEAP
Authentication
through RADIUS
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Red Hat Linux Wireless Security
Techniques
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Open system authentication
Shared key authentication
WEP (40-bit and 104-bit keys)
SSID
802.1x
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Mac OS X Wireless Security
Techniques
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Open system authentication
Shared key authentication
WEP (40-bit and 104-bit keys)
SSID
RADIUS authentication
Firewall protection
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Summary
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How wireless networks work
Popular approaches to wireless networking
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IEEE 802.11
Bluetooth
Types of attacks against wireless networks
Wireless security measures and how to
implement them in client operating systems
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