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WIRELESS NETWORK SECURITY
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Hackers Ad-hoc networks War Driving Man-in-the-Middle Caffe Latte attack
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AD-HOC networks
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WAR DRIVING Searching for Wi-Fi by person in moving vehicle
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MAN-IN-THE-MIDDLE Hotspots have little security Entices computers to log into soft Access Point Hacker connects to real AP – offers steady flow of traffic Hacker sniffs the traffic Forces you to loose connection + reconnect within the hackers AP.
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CAFFE LATTE ATTACK Targets the Windows wireless stack Possible to obtain the WEP key from a remote client Sends flood of encrypted ARP requests Attacker can obtain the WEP key within minutes
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Wireless Intrusion Prevention System (WIPS) Robust way to counteract wireless security risks PCI Security Standard Council published guidelines for large organizations
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WEP: Wired Equivalent Privacy 1999 Secret Keys [Codes to Encrypt Data] Secondary Goal : Control Network Access
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WEP 64,128, 256 bit key 24 bits used for Initialization Vector Each packet includes integrity check
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Stream Ciphers RC4 is a stream cipher Expands a key into an infinite pseudo-random keystream
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What about IVs? RC4 keystream should not be reused. Use initialization vector to generate different keystream for each packet by augmenting the key IV reuse(24 bits)=>16.7 million variations Same shared key in both directions Encryption is vulnerable to collision-based attacks.
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Linear Checksum Encrypted CRC-32 used as integrity check Fine for random errors, but not deliberate ones CRC is linear Can maliciously flip bits in the packet Can replay modified packets!
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WEP Problem #1: No Limit on using the same IV Value more than once.This makes the encryption vulnerable to collision- based attacks. Problem #2 The IV is only 24 bits, there are only 16.7 million possible variations.
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WEP Problem: #3: Master Keys are used directly, when they should be used to generate other temporary keys. Problem #4: Users don’t change their keys very often on most networks, giving attackers ample time to try various techniques.
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802.11i TKIP [Temporal Key Integrity Protocol] AES is a cryptographic algorithm - new hardware may be required 802.1X: used for authentication
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802.1X Keeps the network port disconnected until authentication is complete. The port is either made available or the user is denied access to the network.
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WPA: Wifi Protected Access Subset of 802.11i Master keys are never directly used. Better key management. Impressive message integrity checking.
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WPA: Wifi Protected Access Advantages: IV length has increased to 48 bits, over 500 trillion possible key combinations IVs better protected through the use of TKIP sequence counter, helping to prevents reuse of IV keys.
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WPA: Wifi Protected Access Master keys are never directly used Better key management Impressive message integrity checking.
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802.11i WPA2 WPA2 uses AES (Advanced Encryption Standard) to provide stronger encryption. Enterprise uses IEEE 802.1X and EAP to provide authentication. Consumer uses a pre-shared key, or password. New session Keys for every association- unique to that client. Avoids reuse.
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WPA = TKIP + 802.1X To get a Robust Secure Network, the hardware must use CCMP [Counter Mode CBC MAC Protocol] WPA2 = CCMP+802.1X
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TIPS Change default Administrator Passwords for router. Turn on WPA/WEP Encryption Change the Default SSID Enable Mac Address Filtering
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TIPS Disable SSID Broadcast Do Not Auto-Connect to Open Wi-Fi Networks Assign Static IP Addresses to Devices Turn off DHCP on the router access point
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TIPS Ensure firewall is enabled on your router and also each computer connected.
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TIPS Position the router or Access Point Safely Turn Off the Network during Extended Periods of Non-Use.
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Questions ?
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