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Wireless and WLAN Secuirty, Presented by Vijay


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From Book: Raj Kamal

Published in: Technology
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Wireless and WLAN Secuirty, Presented by Vijay

  2. 2.  Introduction  Wireless Security Issues  Solutions for Security Issues  WLAN Security Issues  Limited RF Transmission  Service Set Identifier (SSID)  MAC Address Control  Authentication Modes  802.1X Authentication  Security in 802.11b: WEP  WPA and WPA2
  3. 3.  Cabir worm can infect a cell phone  Infect phones running Symbian OS  Started in Philippines at the end of 2004, surfaced in Asia, Latin America, Europe, and later in US  Posing as a security management utility  Once infected, propagate itself to other phones via Bluetooth wireless connections  Symbian officials said security was a high priority of the latest software, Symbian OS Version 9.  With ubiquitous Internet connections, more severe viruses/worms for mobile devices have appeared and will continue to strive  Androids are very venerable to attack and remote monitoring.
  4. 4.  Wireless host communicates with a base station  base station = access point (AP)  Basic Service Set (BSS) (a.k.a. “cell”) contains: wireless hosts  access point (AP): base station  BSS’s combined to form distribution system (DS) 
  5. 5.  No AP (i.e., base station)  wireless hosts communicate with each other  to get packet from wireless host A to B may need to route through wireless hosts X,Y,Z  Applications:  “laptop” meeting in conference room, car  interconnection of “personal” devices  battlefield
  6. 6.  Confidentiality  Mobility risks  Integrity  Spoofing  Pre-keying  Reconfiguration  Availability  Eavesdropping  Non-repudiation  Traffic analysis  Resource constraint  Power of detection  Interception  Replay  Stealing of the subscribed services
  7. 7.  Direct signalling with restricted signal strengths  Hardware techniques  Hash  MAC  Encryption  SSL  Checksum or Parity  IPSec  CHAP  RADIUS  AAA
  8. 8.  Involves a radio transmitter and receiver  Not possible to set up absolute physical boundary  Anyone can listen to the transmissions  Encryptions can be easily cracked by hacking tools like Backtrack
  9. 9.  802.11b  up to 11 Mbps  802.11a  up to 54 Mbps  802.11g  up to 54 Mbps  802.11n  up to 150 ~ 600 Mbps  All have base-station and ad-hoc network versions
  10. 10. Limited RF Transmission  Control the range of RF transmission by an access point.  It is possible to select proper transmitter/antenna combination that will help transmission of the wireless signal only to the intended coverage area.  Antennas can be characterized by two features – directionality and gain.  Omni-directional antennas limit coverage to better-defined area.
  11. 11. Service Set Identifier (SSID)  SSID is a network name (ID of BSS or Cell) that identifies the area covered by an AP.  The SSID can be used as a security measure by configuring the AP to broadcast the beacon packet without its SSID
  12. 12. MAC Address Control  Many access points support MAC address filtering.  Similar to IP Filtering.  The AP manages a list of MAC addresses that are allowed or disallowed in the wireless network.
  13. 13.  Two types of client authentication are defined in 802.11  Open System Authentication  Shared Key Authentication  Open System: need to supply the correct SSID  Allow anyone to start a conversation with the AP  Shared Key is supposed to add an extra layer of security by requiring authentication info as soon as one associates
  14. 14.  Client begins by sending an association request to the AP  AP responds with a challenge text (unencrypted)  Client, using the proper WEP key, encrypts text and sends it back to the AP  If properly encrypted, AP allows communication with the client
  15. 15.  Primary built security for 802.11 protocol  Uses 40bit RC4 encryption  Intended to make wireless as secure as a wired network  Unfortunately, since ratification of the 802.11 standard, RC4 has been proven insecure, leaving the 802.11 protocol wide open for attack
  16. 16.  Attacker sets NIC drivers to Monitor Mode  Begins capturing packets with Airsnort  Airsnort quickly determines the SSID  Sessions can be saved in Airsnort, and continued at a later date so you don’t have to stay in one place for hours  A few 1.5 hour sessions yield the encryption key  Once the WEP key is cracked and his NIC is configured appropriately, the attacker is assigned an IP, and can access the WLAN
  17. 17.  Flaws in WEP known since January 2001 - flaws include weak encryption (keys no longer than 40 bits), static encryption keys, lack of key distribution method.  In April 2003, the Wi-Fi Alliance introduced an interoperable security protocol known as WiFi Protected Access (WPA).  WPA was designed to be a replacement for WEP networks without requiring hardware replacements.  WPA provides stronger data encryption (weak in WEP) and user authentication (largely missing in WEP).
  18. 18.  WPA includes Temporal Key Integrity Protocol (TKIP) and 802.1x mechanisms.  The combination of these two mechanisms provides dynamic key encryption and mutual authentication  TKIP adds the following strengths to WEP:  Per-packet key construction and distribution: WPA automatically generates a new unique encryption key periodically for each client. This avoids the same key staying in use for weeks or months as they do with WEP.  Message integrity code: guard against forgery attacks.  48-bit initialization vectors, use one-way hash function instead of XOR
  19. 19.  In July 2004, the IEEE approved the full IEEE 802.11i specification, which was quickly followed by a new interoperability testing certification from the WiFi Alliance known as WPA2.  Strong encryption and authentication for infrastructure and ad-hoc networks (WPA1 is limited to infrastructure networks)  Use AES instead of RC4 for encryption  WPA2 certification has become mandatory for all new equipment certified by the Wi-Fi Alliance, ensuring that any reasonably modern hardware will support both WPA1 and WPA2.
  20. 20.  Wireless technologies are more venerable to attacks  Easy to gain access through attacks (Passive, active, Dictionary, Hijacking etc.)  High level of encryption is needed to secure the line  Security is continuously increasing as evident from the bit length of key used for encryption (16, 32, 64, 128 and now 256 bit)