In this lesson,
we'll explore wireless infrastructure security.
Wireless infrastructure security is
a critical aspect of any organization's IT strategy
and as wireless networks have become increasingly widespread
in our organization, it's very important
that you understand how to secure them effectively.
So in this lesson, we will dive into the importance
of wireless access point placement, site surveys
and heat map to ensure
that your wireless infrastructure is secure.
First, let's talk about where your wireless access
points should be placed and installed.
A wireless access point, also known as the WAP
is a device that allows wireless devices to connect
to a wired network using the 802.11 Wi-Fi standards
and protocols.
The placement
of these wireless access points is important to consider
in terms of achieving both optimal network performance
and increased levels of security.
Your wireless access point placement will significantly
impact the range, coverage and the signal strength
of your organization's wireless network.
If you can properly place your wireless access points
you can ensure that your organization's wireless
network will cover the entire physical area
of your office spaces without leaving dead zones
or areas without any coverage by wireless signals.
However, proper access point placement isn't just
about achieving good coverage for your networks.
It's also a huge concern
in terms of wireless security of your wireless network.
If you place the wireless exit point
near a window or an external wall of your facility,
the wireless signal may extend
out past the physical boundaries of your building.
This provides an increased coverage zone that could
allow unauthorized individuals
or threat actors to access your wireless network even
if they are located outside of your facility.
For example, a threat actor could park their car
in your parking lot next to your building
and if an access point is located too close
to the exterior wall of the building
then the wireless network signal could be obtained safely
from the parking lot.
For this reason, you should normally place your wireless
access point near the center of the facility and away
from windows and external walls to minimize the risk
of unauthorized access.
This is especially true if your wireless access points are
using omnidirectional antennas that broadcast the signal 360
degrees in every direction.
Alternatively, if you need to place a wireless access point
on one of your exterior walls, then you should select a
unidirectional antenna that only broadcasts the wireless
signal in one direction.
In works towards your facility
and this will prevent an attacker from gaining access
to the network from your parking lot or other areas outside
of your facilities.
When placing your wireless access point, you should always
place the access point in a higher location, such
as placing it on top of a shelf or mounting it
to the ceiling.
This will help maximize coverage and minimize interference
with your wireless network.
If you're trying to install a wireless network
in a large building, though, you'll not be able to
adequately cover the entire building
with a single wireless access point.
So instead, you need to install them in an extended service
set or ESS configuration where multiple wireless access
points work together to create one large merge coverage zone
across the entire facility and provide seamless coverage
as a user moves throughout the facility
automatically switching from one wireless access
point to another,
while still remaining on the same enterprise network.
When setting
up multiple wireless access points that are working together
in extended service set configuration
it's important that you consider interference
between different wireless access points since they are only
a few channels that most wireless access points can support
and the SEC approved frequency bands for wireless networks.
The two most common types
of interference are co-channel interference
and adjacent channel interference.
With co-channel interference
you start to experience interference
because there are two wireless access points
that are providing overlapping coverage in the same area
and they're using the same channel
or frequency bands to create their coverage areas.
Because
of these two access points using the same frequencies
or channels, it will cause those signals to collide
and then the data must be re-transmitted again
and again until it successfully is transmitted.
This retransmission will slow down your wireless networks
since it is adding additional traffic
to your wireless networks.
On the other hand
adjacent channel interference will occur when
the channel selected
for your adjacent wireless access points do not
have enough space between the channels
which causes some overlapping other frequencies
or signals being transmitted
which can cause a significant number
of errors and loss of bandwidth.
For example, if two access points within range
of one another or configured in the 2.4 gigahertz band
with channels one and six, they will not overlap.
But if a third access point is added using channel three
it will use part of the spectrum used in both of the WAPs
and all three networks will suffer from interference.
This is because in the 2.4 gigahertz band
there are only 11 frequency bands
or channels that are allowed to be used.
Each channel from one to 11 is considered to
be 22 megahertz wide, but there's only a hundred megahertz
of total frequency bands available
so there's a lot of overlap between the different channels.
For example, channel six operates a 22 megahertz channel
centered on 2.437 gigahertz.
This means that there's a strong overlap with channels five
and seven and a little less interference with channels four
and eight.
Since channel six operates at a peak efficiency
of 2.437 gigahertz, but then the strength of the signal
deteriorates and weakens as the signal spreads out
from 2.436 gigahertz to 2.448 gigahertz to
create a circular channel pattern on a frequency chart.
For this reason, you should always select channels one, six
and 11 if you're operating in a 2.4 gigahertz wireless
frequency band.
Since these channels do not overlap with each other
and they will not interfere with each other.
Now that we have a little interference theory covered
let's move into the more practical side of figuring out
if you have interference in your wireless network, and
if your wireless access points have been placed
in the right locations to provide us with the best coverage.
To do this, we'll perform a site survey
and create a heat map.
A site survey is a process of planning
and designing a wireless network to provide a solution
that will deliver the required wireless coverage, data rates
network capacity, roaming capability, and quality
of service levels.
A site survey usually
involves a site visit to test
the radio frequency interference
and to identify optimal installation locations
for access points by scanning the airways
in order to identify any device that is already configured
and is operating
in that wireless frequency band that we are considered using
for our wireless network.
During your site survey
you'll usually create something known as a heat map.
A heat map is a graphical representation
of your wireless coverage
the signal strength and frequency utilization data
at different locations on that map,
with each individual value being represented
as a different color.
Heat maps are really
useful when you're trying to troubleshoot coverage issues
or dead zone areas that have no coverage, as well
as determining any areas where the signal strength is too
strong.
Also, these heat maps are useful
in identifying the areas where your wireless network
signal may be leaking outside of physical boundaries
of the building and could potentially allow
for an attacker to gain unauthorized access to the network.
For example, if you were hired
by a company as a cybersecurity and consultant to
determine the proper configuration and placement
of their wireless network, you should first
conduct a site survey to identify the optimal locations
for the wireless access points by determining what
other wireless networks are already nearby.
Then after installing the new wireless access points
you should create a heat map to visualize the
actual coverage of the network.
The heat map should show that the signal is strong
in the central areas of the building
but weak near the outer edges.
This might indicate that additional WAPs are needed
near the edges of the building
and use some unidirectional antennas to
focus the signal back into the building instead
of letting it leak outside of the building.
On the other hand, at the heat map shows
that the signal is leaking outside the building.
That will indicate that the wireless access points
need to be repositioned to prevent unauthorized access
from outside the building, or the signal strength
of those wireless access points may need to be decreased so
that the signal remains within the walls of your facility.
So remember, the placement
of your organization's wireless access points is crucial
for ensuring the proper network performance
and security for your wireless networks.
The wireless access points should be placed
in central locations within the building
and remain away from the windows and external walls.
A site survey is an essential step
in planning a secure wireless network
and you should create a heat map at the end
of your installation to show a graphical representation
of the coverage area
and strength of your wireless network signals.
These heat maps can then be used
in areas where coverage is too weak, coverage is too strong
or coverage is leaking outside the walls of your facility.