Evolution of WLAN Security

1
Evolution of WLAN Security

• Presented by
• Khalid AlShehri
• CSE 7339

2
802.11 Security Specifications

• MAC address filtering
• Each AP configured with a list of MAC addresses
  to make sure that only stations on the list can
  access the network
• Spoofing an authorized MAC address!
• Wired Equivalent Privacy (WEP)
• Uses RC4 symmetric key encryption algorithm
• 40-bit key shared between the AP and wireless
  client

3
WEP contd.

• Serious security flaws were present in the
  protocol. WEP was considered as a broken
  protocol.
• Experienced hackers can crack the WEP keys in a
  busy network within 15 minutes.
• Tests reveals that WEP remains insecure at any
  key size

4
IEEE 802.11i

• New WLAN security standard that adds stronger
  encryption, authentication, and key management
  strategies
• The default mode for implementing encryption and
  message authentication is based on AES
• When WEP was broken, there were millions of
  installed APs without practical security solution
• Problem Hardware needed to implement AES is
  different from that needed for RC4
• Solution Design a secure protocol that
  accommodate WEP hardware (TKIP)

5
802.11i contd.

• Consists of three main components organized into
  two layers
• Lower layer improved encryption algorithms
• TKIP legacy equipment
• AES future WLAN equipment
• Upper layer port based access control (802.1x)

6
IEEE 802.1X

• Original purpose behind 802.1X was to protect
  ports of the Ethernet switch (wired)
• Complete security solution for Wireless LANs?
• No, it is only a small part of the solution
• Addresses the issue of user authentication in WEP
  

7
Temporal Key Integrity Protocol (TKIP)

• Purpose to upgrade WEP systems to be secure
• TKIP uses RC4 as WEP
• Addresses WEPs known exposures
• Changes the temporal keys every 10000 packets

8
Wi-Fi Protected Access (WPA)

• Industry couldn't wait until the lengthy process
  of standards ratification was completed.
• Wi-Fi Alliance adopted a new security approach
  based on the draft of 802.11i
• Implements 802.1X to enforce authentication
• Apply TKIP on existing RC4 WEP to impose strong
  data encryption

9
WPA Contd.

• A major security improvement in wireless
  environment
• Vendors can transit to the WPA standard through a
  software upgrade
• There are still potential encryption weaknesses
  in TKIP.
• successful crack is expected to be heavy and
  expensive.
• Performance may be sacrificed due to a more
  complex authentication and encryption protocols.

10
WPA2

• WPA2 is the approved Wi-Fi Alliance
  implementation of 802.11i
• Uses AES (stronger encryption mechanism)
• Backward compatible with WPA
• WPA2 is not being released to address any flaws
  in WPA.

11
Conclusion

• Wireless security is one of the most
  misunderstood aspects of wireless technologies.