Evolution of wireless LAN security standards

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Evolution of wireless LAN security standards

• Team members
• Bo Li
• Daniel Menchaca
• Harold Lee
• Narendra Kamat

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Motivation for wireless LAN security

• Wireless LAN is becoming very popular
• Wireless LAN is not very securely protected
• Initial proposed WEP in IEEE 802.11 was weak
• Modified WEP2 cannot solve the exposed problem
  due to inherited mechanism from WEP
• Design flaws have been reported on newly
  developed standard IEEE 802.1x
• Can 802.11i protect our wireless LAN?

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Wired Equivalent Privacy (WEP)

• Extensively analyzed. (Usually unfavorably!)
• Integrity Control by CRC-32 checksum.
• Linear can be easily modified.
• RC4 rand. gen. takes a secret key and an
  initialization vector as input
• Distribution of secret key k infrequent (hard to
  manage)
• Sequence space of 24-bit IV is rapidly used up.
  (IV collision)
• Initial challenge/response sequence (with IV)
  visible to attacker.
• IP redirection, reaction attack, etc.
• This solution does not inspire confidence!!

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Overview of 802.1x

• Uses Extensible Authentication Protocol (EAP)
• Provides key management

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802.1x vulnerabilities

• Absence of mutual authentication
• One way authentication of supplicant.
• Adversary acting as access point leads to
  Man-in-the-middle attack
• Session hijacking
• Attacker spoofs MAC of AP and disassociates
  client
• Next, it spoofs MAC of client and gains
  connection

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802.11i

• 802.1x
• Robust authentication
• Key distribution
• TKIP (upgrade path)
• Fixes WEP issues
• Backward compatible
• CCMP (mandatory)
• Advanced Encryption Standard (AES)
• Privacy, integrity, authenticity

Upper Layer Auth. (ULA)
802.1x authentication
TKIP (Temporal Key Integrity Protocol)
CCMP (counter mode CBC-MAC Protocol)
Encryption Algorithms
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Expected Results

• Understanding architecture and weaknesses of WEP
• Analysis of 802.1X, including both state
  machines.
• Proposal for new state machine.
• Evaluation of proposed standard 802.11i
• Recommendations for improvement and new
  direction in evolution.

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Thank You!