MAC access control lists

Hackers are most interested in getting one of
your employees’ laptops because it is easy to steal and is already enabled
on your internal access control list (ACL). One of the problems with just
trying to access your WLAN is that most administrators are wise to the
fact that they can set their wireless access point or router to screen out any
wireless network interface card that does not match their ACL of preprogrammed
unique identification values. If a laptop with an unknown MAC
address tries to log into the network, access is denied. However, if a hacker
steals a corporate laptop, he can take the wireless network interface card
out of the computer and use it on another machine in an attempt to breach
your security and access your protected network resources.

There are certain limitations to using MAC addresses. Not only can
these cards be stolen, but the address itself is transmitted in clear text
without encryption over the WLAN. This makes it very easy to spoof
these types of addresses and find still another way to breach your network.
By understanding the limitations of these security protocols, you
are better able to protect yourself against hacker exploits.