Password Cracking on WiFi | 223

Password Cracking Guarantees
Keep in mind that you are not guaranteed to obtain a password by
using this approach. If the actual password is not in the password
list you provide, there is no way to get a match. You will end up
with a failed crack attempt.
Fern
Fear not if you are reluctant to take multiple steps using the command line to go after
WiFi networks. You can use 
Fern
, a GUI-based application that can be used to attack
different encryption mechanisms. 
Figure 7-6
shows the interface that Fern presents.
You can see from the screen capture that Fern supports cracking WEP and WPA net‐
works.
Figure 7-6. Fern GUI
Once you have Fern running, you need to select the wireless interface you plan to use
and then you need to scan for networks. The selection of the interface is in the left‐
most box in the top row. Next to that is a Refresh button if you have made changes
outside the GUI in order to get them picked up in the interface. “Scan for Access
224 | Chapter 7: Wireless Security Testing

points” is the next button down. That populates a list that Fern will provide to you.
When you select the type of network you want to crack, either WEP or WPA, you will
be presented with the box shown in 
Figure 7-7
. This gives you a list of the networks
that were found. This list is basically the same list we’ve been dealing with up to now.
Figure 7-7. Fern network selection
You may also notice that at the bottom right of the dialog box is a selection button to
provide Fern with a dictionary to use. Just like 
aircrack-ng
, Fern uses a dictionary to
run cracks with, and just as with 
aircrack_ng
, you won’t be able to crack the password
if it is not provided in the dictionary that Fern is given. To get Fern started, you select
one of the networks provided, provide it with a dictionary file, and then click the
Attack button.
Going Rogue
Rogue APs come in two, possibly three, flavors. First, you may get an AP that just
tries to lure you in. It may be named FreeWiFi, or it may be a variation on a legiti‐
mate AP. There is no attempt to do anything other than get people to connect. In the
second kind, an attacker attempts to take over a legitimate SSID. The attacker mas‐
querades as the real network, possibly jamming the legitimate signal. The third one is

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