A note about WEP
While uncommon at this point, some Wi-Fi networks are still encrypted using a protocol known as Wired Equivalent Privacy, or WEP. WEP utilizes an RC4 cipher to create ciphertext from the plaintext and a per-packet key, which is reversed by the receiving device to yield the plaintext. Unfortunately, the implementation of WEP has several critical flaws that allow us to retrieve the WEP key with minimal effort. In this attack, we do not need to guess the WEP key – we can retrieve it with complete accuracy if we can capture a sufficient amount of packets from that WEP-encrypted network.
While outside the overall scope of this chapter, WEP-encrypted networks still exist and may contain items of interest or importance. Thankfully, there is minimal effort required to crack WEP keys. In fact, you only need two components:
- Hardware supporting monitor mode Wi-Fi capture
- Software to capture traffic in monitor mode
aircrack-ngsoftware for cracking WEP...
