Wireless networks introduce security risks like eavesdropping and internal attacks. The 802.11x standards define wireless transmission and authentication using options like SSID, MAC address, WEP, and 802.1x. Deploying wireless safely involves securing access points, transmissions, workstations, and the entire site through measures such as encryption, firewalls, and intrusion detection.

1. Lesson 20-Wireless Security
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2. Overview
Introduction to wireless networks.
Understanding current wireless technology.
Transmission security, authentication
Understanding wireless security issues.
WLAN detection, evaesdroping, active attacks,
Deploying wireless safely.
AP , Transmission, workstation, site security
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3. Introduction to Wireless
Networks
Wireless networks are inexpensive and easy to set up and
use.
But wireless technology opens up some serious security
issues to organizations using them.
As yet no effective solution has been put forward to handle
the risk of wireless networks.
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4. Understanding Current
Wireless Technology
Wireless LANs (WLAN) center around IEEE 802.11x
standards.
These standards allow workstations to establish connections
with a wireless access point (AP).
Access points are in turn connected to wired LAN or another
workstation.
802.11x standard provides for exchange of authentication
information and for encryption of the information.
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6. Understanding Current
Wireless Technology
Standard architectures:
Typical 802.11x standard allows for connectivity up to 150 feet
indoors and 1,500 feet outdoors.
DHCP server in this architecture provides necessary
information that allows proper workstation communication to
network.
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7. Understanding Current
Wireless Technology
Transmission security:
802.11x standard defines Wired Equivalent Privacy (WEP)
protocol to protect information passing over WLAN.
WEP provides authentication, confidentiality, and integrity
services.
Authentication service can be used to authenticate a
workstation to the AP.
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8. Understanding Current
Wireless Technology
Transmission security:
Open System authentication or cryptographic authentication
provides no proof to the AP of the workstation’s identity.
This method leaves the workstation open to attach itself to any
rogue AP.
Authentication and confidentiality services use RC4 algorithm,
which cannot be easily attacked.
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10. Understanding Current
Wireless Technology
Transmission security:
Confidentiality mechanism protects all protocol header
information and data above the 802.11x protocol.
WEP supports 40-bit and 128-bit keys.
WEP does not specify a key management system, which
means that WEP installations rely on static keys.
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11. Understanding Current
Wireless Technology
Transmission security:
Another problem with WEP is that an intruder can capture the
initialization vectors and also determine the encryption key.
Implementation of RC4 in WEP is flawed and open to
compromise.
Integrity check on each packet should be done by using cyclic
redundancy check (CRC) of 32 bits.
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12. Understanding Current
Wireless Technology
Authentication:
Authentication is a part of securing a WLAN.
WLAN users have service set identifier (SSID), MAC address,
WEP, and 802.1x port-based network access control options
for authentication.
These options cannot manage risk of WLAN by themselves.
For a workstation to associate with an AP, it must have the
SSID.
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13. Understanding Current
Wireless Technology
Authentication:
Since SSID is broadcast by many APs, listening workstations
can use it to add themselves to the appropriate network.
Some APs use MAC address authentication to authorize
computers to access the WLAN.
MAC addresses must be transmitted in clear or the network
would not function.
An intruder listening to the traffic could misuse MAC addresses.
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15. Understanding Current
Wireless Technology
Authentication:
802.1X protocol is an add-on to all layer 2 network access
protocols including Ethernet and WLANs.
Use of 802.1X allows for stronger authentication mechanism.
Since mutual authentication is optional with 802.1X, many
default installations will be open to interception attacks.
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16. Understanding Wireless
Security Issues
Use of WLANs involves risks like eavesdropping, direct
internal attacks, and attacks against external sites.
Several tools are available to detect WLANs easily.
WLANs allow computers close to the physical network to
communicate as if on the network.
In WLANs, intruders have the ability to gain access to an
organization’s internal network.
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17. Understanding Wireless
Security Issues
Organizations using WEP are also subject to eavesdropping
because of tools like WEPCrack.
WEPCrack requires the intruder to collect millions of
packets to determine the encryption key.
A passive eavesdropping attack is almost impossible to
detect.
An intruder can attack WLANs internally or externally and
discover and exploit vulnerabilities. 17

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19. Understanding Wireless
Security Issues
It is difficult to find the physical location of an intruder since
IP addresses are not location-specific.
The organization may be legally responsible if an intruder
gained access to the internal network.
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20. Deploying Wireless Safely
Deployment of WLAN should be preceded by a thorough
risk assessment.
Proper security measures should be implemented by the
organization to reduce risk while deploying a WLAN.
Access point security, transmission security, workstation
security, and site security measures assist in risk
management.
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21. Deploying Wireless Safely
Access point security:
Configuring the AP is an important starting point.
Setting WEP key and using MAC addresses help to limit AP
detection.
HTTPS should be used to manage AP when possible along with
strong passwords.
APs should be positioned so that their range outside the facility
is limited.
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22. Deploying Wireless Safely
Transmission security:
Though WEP has serious vulnerabilities, it does not provide
easy access to casual intruders.
It is appropriate to use another encryption system along with
WEP.
WLAN can be treated as a semi-trusted or untrusted segment
of the network.
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23. Deploying Wireless Safely
Workstation security:
It is possible to directly attack workstations on a WLAN.
Appropriate anti-virus software or personal firewalls should be
used on workstations for protection.
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24. Deploying Wireless Safely
Site security:
WLANs should be placed on their own network and protected
with a firewall between WLAN and the internal network.
An intrusion detection system should be deployed on WLAN to
detect unauthorized visitors.
Organizations must address illegal or unauthorized APs by
performing periodic wireless assessments on their networks.
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26. Summary
Wireless LANs center around the 802.11x standards.
WEP provides authentication, confidentiality, and integrity
services.
WLAN users have service set identifier (SSID), MAC address,
WEP, and 802.1x port-based network access control options
for authentication.
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27. Summary
Security risks in WLANs include eavesdropping, direct
internal attacks, and attacks against external sites.
Security measures like access point security, transmission
security, workstation security, and site security assist in
managing risk.
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