Router Charts

Click for Router Charts

Router Ranker

Click for Router Ranker

NAS Charts

Click for NAS Charts

NAS Ranker

Click for NAS Ranker

More Tools

Click for More Tools

Wireless How To

Introduction

There is a new version of this article here.

Previously, we showed you how to secure your wireless with industrial strength RADIUS authentication via WPA-Enterprise. It turns out that there's a little back-story there. So, in traditional Tarentino fashion, now that we've already seen the ending, let's back up to the beginning: cracking WPA-PSK.

Wi-Fi Protected Access (WPA) was created to solve the gaping security flaws that plagued WEP. Perhaps the most predominant flaw in WEP is that the key is not hashed, but concatenated to the IV, allowing completely passive compromise of the network. With WEP, you can literally sit in your car listening for packets on a network. Once you have captured enough of them, you can extract the key and connect to the network.

WPA solves this problem by rotating the key on a per-packet basis, which renders the above method useless. However, nothing is perfectly secure, and WPA-PSK is particularly vulnerable during client association, during which the hashed network key is exchanged and validated in a "four-way handshake".

The Wi-Fi Alliance, creators of WPA, were aware of this vulnerability and took precautions accordingly. Instead of concatenating the key in the IV (the weakness of WEP), WPA hashes they key using the wireless access point's SSID as a salt. The benefits of this are two-fold.

First, this prevents the statistical key grabbing techniques that broke WEP by transmitting the key as a hash (cyphertext). It also makes hash precomputation via a technique similar to Rainbow Tables more difficult because the SSID is used as a salt for the hash. WPA-PSK even imposes a eight character minimum on PSK passphrases, making bruteforce attacks less feasible.

So, like virtually all security modalities, the weakness comes down to the passphrase. WPA-PSK is particularly susceptible to dictionary attacks against weak passphrases. In this How To, we'll show you how to crack weak WPA-PSK implementations and give you some tips for setting up a secure WPA-PSK AP for your SOHO.

NOTE!Warnings:
  • Accessing or attempting to access a network other than your own (or have permissions to use) is illegal.
  • SmallNetBuilder, Pudai LLC, and I are not responsible in any way for damages resulting from the use or misuse of information in this article.

NOTE!Note: The techniques described in this article can be used on networks secured by WPA-PSK or WPA2-PSK. References to "WPA" may be read "WPA/WPA2".

More Wireless

TRENDnet logo

How Powerline Can Solve Your Wi-Fi Woes - There's a better way to get WiFi Everywhere™.

Wi-Fi System Tools
Check out the new Wi-Fi System Charts, Ranker and Finder!

Featured Sponsors


Win This!

Insteon Giveaway

You could win a kit of Insteon Home Automation products!

Learn How!

Support Us!

If you like what we do and want to thank us, just buy something on Amazon. We'll get a small commission on anything you buy. Thanks!

Over In The Forums

Hey guysI have been having issues with a lot of WiFi routers bought for the pub over the years...currently I am using Asus RT-AC68U, bought 2 years ag...
I've been looking forward to the most recent Xbox dashboard update because of its ability to choose Xbox Live ports, so I can finally disable UPnP on ...
Apologies for the long post - I wanted to provide as much detail as I could. I've been having an issue for the last week and I can't seem to get to th...
I'm in a situation with temporary housing where I am flatting, and can't really expect to be able to connect an ethernet cable from my PC to the route...
Pretty simple to describe what I am looking for. A (4 port at least) switch with integrated wireless. (WAN port connected to internet via gigabit port...

Don't Miss These

  • 1
  • 2
  • 3
Get Backblaze Now!