Router Charts

Router Charts

Router Ranker

Router Ranker

Router Chooser

Router Chooser

NAS Charts

NAS Charts

NAS Ranker

NAS Ranker

More Tools

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

Featured Sponsors


Win This!

Linksys Linksys LAPC1750PRO

You could win a Linksys LAPC1750PRO AC1750 Pro Dual-Band Access Point

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!

Top Performing Routers

AC3200
AC2600
AC1900
AC1750
AC1200

Top Performing NASes

NoRAID
RAID1
RAID5

Over In The Forums

Hi I am using a ISP (Media Force) to log on and use the internet, however when I connect my phone (Samsung S5) to the wifi network, I'm logged out an...
Hello All, I got a 68U running the latest Merlin and it is solid as rock. Well over a year ago, I started using DNSCrypt along with DNS filtering to ...
RT-AC56U_380.57_0.trx I've tried all 3 download options.
Is this firmware interchangeable and backwards compatible? Specifically, can I use RT-AC3200 firmware on an RT-AC3100?
http://www.microcenter.com/product/454481/RT-AC1200_Dual_Band_80211ac_Wireless_Router I'm interested in this mostly as a distant AP for people looki...

Don't Miss These

  • 1
  • 2
  • 3