Wireless Security

Michael Sansone & Michael Marcucci

Depreciated wireless technology that uses a password to encrypt the wireless data and ensure that data sent across the air is secure and is also responsible for user authentication to the access point.
WEP cracking works on based on WEP vulnerabilities
Initially the password was used to create the keystream, by repetition, (ie. password="pass1" keystream="pass1pass1pass1...") and the keystream was combined with the plain text (this was bad, knowing a packet meant knowing the password)
Later, IV's were introduced and used in tandem with the key to encrypt the data
PROBLEM: IV's were predictable (psuedo-random) and the 24bit length of an IV meant wrapping would occur.
Methods to crack WEP involve sending the an arp packet to a router which in turn sends a response back with an incremented IV, eventually all IV's would be captured and wrapping occurs. Once enough packets are captured and the IVs wrap a few more times, the packets can be aligned and the IV's subtract from the encryption exposing the keystream with just the password.
Encryption:

Originally, cracking the preshared key involved waiting for client to connect and listening to the four way handshake that occurs.
WPA uses a public and private key combo
Via the four-way handshake the public key can be acquired
This allows for offline cracking by guessing the password, however brute forcing (96^64 combos) takes forever.
HOWEVER:

WPA-TKIP-PSK is vulnerable to the Beck-Tew Attack
Which easily allows ARP poisoning or DNS spoofing
This uses the same vulnerability as WEP, which is that WPA also allows keystream reuse. (However, there is a limit imposed, which is 1 minute intervals).
The key stream is captured by sending a spoofed ARP packet and looking for responses, ie. good response 68 bytes, bad response 40 bytes.
Once the keystream is found, 7-15 packets can be sent and accepted.

WPA-AES is the new standard and must be brute forced or cracked with a dictionary
Difference between WPA & WPA2, WPA2 simply does not allow TKIP and forces AES

The demo, showed how easy it is to capture a handshake, either by waiting passively for a connection, or sending a de-authentication packet to a client and waiting for the to reconnect, often done automatically.
However, having a secure password mitigates any chance of guesses occurring, also changing your password forces the handshake to become invalid.

Wifi protected setups(WPS) use an 8 digit number to allow connections, (WPS pins do not change)
10^8 possibilities (~600 days to guess if limited to 1 guess a second)
HOWEVER:

Due to the implementation of WPS last digit is a checksum => 10^7 possibilities
Final Flaw, the first and last 4 digits are independently authenticated, therefore the first four digits (10^4) possibilities would take 2.h and the final 3 (10^3) would take 16 min
So bruteforcing all possible combos of WPS would take ~3h

Also, some manufacturers use bad algorithms to initialize WPS
An attacker only has to figure out some meta information about the AP and preform some calculations to get the WPS pin

The Demo showed how easy it is to attack WPS setups, it is hard to guess at 1 pin/second, but even at 5 seconds per pin, statistically a pin could be guessed in under 8 hours.
Furthermore, it is not just that the pin is captured, the WPA password is returned as well. Either the pin or the password can then be used to connect.

Router configuration, whereby the mac address assigned to each network card is used to determine who has access to a network
WHY its bad:

Hiding SSID (Network Name)
It works by disabling the sending of beacons so the AP cannot be discovered
However , this is just one way that the SSID is sent over the air and this gives a false sense of security

Kismet can be used passively, wait for a client to connect
Netstumbler or inSSIDer can be used to disassociate a client and force them to reconnect

The demo showed how easy it was to do this, a packet capturing utility is used to watch the network, and all we had to do was wait for a client to connect or force a client to disconnect (automatically tries to reconnect).

3 types: Friendly, Evil, Evil-Twin
A Friendly Rogue AP is one that an employee may setup in a workplace. If connected to your network this access point will become the weak point in your security.

An Evil-Twin AP is one that mimics an existing access point's SSID (network name).

Sending de-authentication packets
As a client will connect to stronger signals being a more powerful than the real AP or closer

Make sure a user is trusted as any person connected can perform a man in the middle attack
TO FIX : Try to setup the network so that clients cannot talk to each other

WIPS (depreciated) can be used in WEP systems to prevent password cracking by sending "chaff" which mimics/spoofs the APs packet but uses a different password/keystream
This is also called cloaking an AP
This works to confuse password cracking programs
Why depreciated: A. WEP is easy to crack & slow. B. Tools like airdecloak-ng can be used to remove most of the chaff. ~80%

Laptops not connected to AP's are still susceptible to intrusion
A packet can be crafted such that it would cause the card to run commands or code.
This has been proven, but it is not mainstream.
Vulnerability : Bad Drivers / Hardware
Same premise as the Nike Bluetooth band from other presentation
To Prevent : Update Drivers and turn off wireless radio when not using it