Page 243 - StudyBook.pdf

Communication Security: Wireless • Chapter 4 227

Creating a hijacked AP DoS attack requires additional tools that can be found
on many security Web sites. See the earlier section “Sample Hijacking Tools” for a
starting point to acquiring some of the ARP spoofing tools needed.These tools are
not very complex and are available for almost every computing platform available.
Many apartments and older office buildings do not come prewired for the
high-tech networks used today.To add to the problem, if many individuals are set-
ting up their own wireless networks without coordinating the installations, prob-
lems can occur that will be difficult to detect.
Only a limited number of frequencies are available to 802.11 networks. In fact,
once the frequency is chosen, it does not change until manually reconfigured.
Considering these problems, it is not hard to imagine the following situation
occurring:
A man goes out and purchases a wireless AP and several network cards for his
home network.When he gets home and configures his network, he is extremely
happy with how well wireless networking works. Suddenly, none of the machines
on the wireless network are able to communicate.After waiting on hold for 45 min-
utes to get through to the tech support line of the vendor who made the device, he
finds that the network has magically started working again, and hangs up.
Later that week, the same problem occurs, except this time he decides to wait
on hold.While waiting, he goes outside and begins discussing his frustration with
his neighbor. During the conversation, his neighbor’s kids come out and say that
their wireless network is not working.
So, they begin to do a few tests (while still waiting on hold). First, the man’s
neighbor turns off his AP (which is usually off to “protect” their network).When
this is done, the original person’s wireless network starts working again.Then they
turn on the neighbor’s AP again and his network stops working again.
At this point, a tech support representative finally answers and the caller
describes what has happened.The tech-support representative informs the user that
he needs to change the frequency used in the device to another channel. He
explains that the neighbor’s network is utilizing the same channel, causing the two
networks to conflict. Once the caller changes the frequency, everything starts
working properly.
Protecting Against DoS and Flooding Attacks

There is little that can be done to protect against DoS attacks. In a wireless envi-
ronment, an attacker does not have to even be in the same building or neighbor-
hood.With a good enough antenna, an attacker is able to send these attacks from a
great distance away.

www.syngress.com