Transcript Cohen - Tightening Wireless Networks

Tightening Wireless Networks
By
Andrew Cohen
Question
Why more and more businesses aren’t
converting their wired networks into wireless
networks?
The truth is that a wireless network “poses a
much greater threat because the attacker has
easy access to the transport medium. In wired
networking, an attacker usually must
penetrate some physical security perimeter to
gain network access. But wireless
networking’s broadcast nature makes
traditional link-layer attacks readily available
to anyone wishing to create mischief”
(Arbaugh).
WiFi network
• A WiFi network, sometimes called Wireless
Local Network (WLAN) consists of two main
components; clients and access points
– An access point is like a door to the wireless
network.
– A client is you…
It utilizes radio waves for communication
Goals of Wireless Security
• Confidentiality
• Integrity
• Availability
A modern wireless router normally comes
with several security features; Service Set
Identifier, Wired Equivalent Privacy (WEP), and
MAC Address Filters.
Service Set Identifier (SSID)
It broadcasts the name of its wireless router to
others who are searching for access points
Wired Equivalent Privacy (WEP)
A technique dubbed RC4 stream cipher
applies the 40 or 104 bit symmetric key to the
data
MAC Address Filters
hexadecimal value assigned to a piece of
hardware
Secure Enough?
• Service Set Identifier
• Wired Equivalent Privacy (WEP)
• MAC Address Filters.
What do you need for hacking?
cheap computer with a wireless LAN card to
intercept the signal.
Hack SSID?
• Stumbling
– actively detect networks
• Sniffing
– capturing, all the traffic moving through the air
Hack MAC?
• ARP Spoofing (or ARP Poisoning)
– It only requires a simple change in the operating
system’s registry.
Hack WEP?
• WEP uses RC4 which takes short groups of
data and expands it into an incredibly long
random bunch of characters.
• Initialization Vector (IV)
– only 24 bits long
How to improve WiFi security?
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•
•
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Change default username and password
Turn off SSID
Enable MAC Filtering
Turn on WEP
Limit the # of clients (through DHCP)
Change the default ip address (192.168.0.1)
How to improve WiFi security?
• Virtual Private Network (VPN)
• Intrusion Detection System (IDS)
• Temporal Key Integrity Protocol (TKIP)
– a new encryption scheme
• WiFi Protected Access (WPA)
– Wireless protocol
• Strong Password (over 20 characters)
802.11i protocol
Incorporate all the advantages of WEP, WPA,
AES, TKIP, and a few other encryption
schemes.