Tuesday, June 23, 2015

Wireless Security Brief

  • Cipher:
    • An algorithm which converts plain text into encrypted text & vice versa. i.e. it provides cryptography by providing both encryption and decryption.
  • Properties of Ciphers
    • Symmetric / Asymmetric: Asymmetric uses public key for encryption & private key for decryption. 
    • Stream / Block

  • Security Standard / Encryption Method provides:
    • Encryption: Provides confidentiality of data
    • Data Integrity: Provides prevention from Bit flipping, Forgery attacks, Fragmentation attacks, Redirection attacks, Impersonation attacks
    • Sequencing: Defeats Replay AttackRe-injection attack.
  • Different Security Standards

  • WEP
    • WEP was used for encryption only not for authentication.
    • Dynamic WEP used 802.1x for authentication & WEP for encryption.
  • Security related Information Elements
    • RSN Information Element: Present when WP2 is configured. (more info)
    • Vendor Specific: WPA Information Element:Present WPA is configured.
    • Both these IEs are available in Beacon frames, Probe Response frames, Association Request Re-association Request frames.
  1. Both IEs are present when WPA2 Mixed Mode is used. 
  2. Authentication Key Management (AKM) suite  gives info about whether PSK or Enterprise (802.1x) is used.
  3. Pairwise suite gives encryption method to be used for unicast packets.
  4. Group key suite gives info on the encryption method to be used for broadcast. In mixed mode, this element will fallback to TKIP as AP broadcast / Multicast is supposed to be for both WPA & WPA2 clients. 
PTK / GTK in Mixed Mode

  • 802.1x Authentication Methods
    • http://wiki.freeradius.org/protocol/EAP 
    • http://wiki.freeradius.org/protocol/EAP-PEAP 

  • Seven EAP Methods Required for WiFi Certification
    1. EAP-TLS
    2. EAP-TTLS
    3. PEAPv0 (EAP-MSCHAPv2)
    4. PEAPv1(EAP-GTC)
    5. EAP-FAST
    6. EAP-SIM
    7. EAP-AKA

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