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WIRELESS SECURITY by Prof. Russell Jones

WIRELESS SECURITY by Prof. Russell Jones. WIRELESS COMMUNICATION ISSUES. Wireless connections are becoming popular. Network data is transmitted using radio waves. Physical security is no longer sufficient. Transmissions can be intercepted outside the building where the data originates.

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WIRELESS SECURITY by Prof. Russell Jones

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  1. WIRELESS SECURITYbyProf. Russell Jones

  2. WIRELESS COMMUNICATION ISSUES • Wireless connections are becoming popular. • Network data is transmitted using radio waves. • Physical security is no longer sufficient. • Transmissions can be intercepted outside the building where the data originates.

  3. HOW WIRELESS NETWORKING WORKS • Institute of Electrical and Electronics Engineers (IEEE) 802.11 is the standard • 802.11b & 802.11g • Security Standard • 802.1x & 802.11i (June 2004) • Can use various upper-layer protocols

  4. WIRELESS INFRASTRUCTURE MODE NETWORKING

  5. WIRELESS THREATS • Theft of service • Free use of Internet access • Free use of applications • Eavesdropping • Confidential Information • Financial & Health Security Laws • Unauthorized access • Change of Data, insert viruses, disable system

  6. WIRED EQUIVALENCY PRIVACY (WEP) • Provides encryption and access control • Media Access Control • Uses the RC4 encryption algorithm • Originally - 24-bit and 40-bit encryption • New versions support 128-bit encryption

  7. WEP KEYS • An attacker can discover the WEP key by using a brute-force attack. • All computers use a single shared WEP key. • WEP does not define a secure means to distribute the key. • WEP designed to use manual distribution of keys

  8. ADVANTAGES OF WEP • All messages are encrypted. • Privacy is maintained. • WEP is easy to implement. • WEP provides a basic level of security. • Keys are user definable and unlimited.

  9. DISADVANTAGES OF WEP • A hacker can easily discover the shared key. • You must tell users about key changes. • WEP alone does not provide sufficient wireless local area network (WLAN) security. • WEP must be implemented on every client and AP.

  10. WiFi Protected Access (WPA) • Improved encryption using Temporal Key (TKIP) • Provides integrity testing • Scrambles the key fields • Use of smart card devices with EAP • Allows for MAC filtering

  11. 802.11i PROTOCOL (June 2004) • Improved authentication (PEAP, EAP) • Certificate-based (client and RADIUS) • Do not use EAP-MD5 (No protection to client password) • Requires authentication before access • Dynamic key assignment (Every 10 minutes) • Increased encryption (128-bit) • Adding preferred networks to clients

  12. Authentication Process • Wireless client contacts uncontrolled AP port • The AP requests identity of client • AP create a RADIUS request and transmits • RADIUS checks to see if AP is approved • Checks credentials and policies on client • If ok, AP generates WEP key and passed to client • Client access controlled port with WEP key

  13. Wireless Threats • Attack by intruder with wireless connection • Use Switches instead of Hubs • ARP Spoofing • Warn client not to accept credential changes • Evil Twin Attack • Authentication of Access Points • WEP Attacks • www.airsnort.com & www.netstumbler.com

  14. BASIC DEFENSES AGAINST WIRELESS ATTACKS • Limit the range of radio transmissions. • Change the default SSID. • Disable SSID broadcast. • Use newer Access Points • Search for unauthorized access points (APs). • Restrict access by limiting access to specific media access control (MAC) addresses. • Separate the wireless segment from the rest of the network.

  15. BASIC DEFENSES AGAINST WIRELESS ATTACKS • Increase WEP encryption levels. • Change the default WEP keys. • Measure the signal strength. • Protect SNMP. • Do not use Shared Key Authentication • Secure clients • Use honeypots

  16. CONCLUSION • Access your particular security needs • Determine efficiency versus security trade-off • Any key is hackable • Use longest key feasible (not necessarily available) • Change as often as feasible • Remember the Wireless Rule • The more flexible access to a network is made, the less secure the environment

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