A. Wireless Approaches
Most of the current approaches for detecting rogue APs are
rudimentary and easily evaded by hackers. Some
organizations have equipped IT personnel with wireless
packet analyzer tools (e.g., sniffers) on laptops and handheld
devices (e.g., AirMagnet [4] and NetStumbler [5]), forcing IT
personnel to walk the halls of the enterprise or campus
searching for rogue APs. This method is generally ineffective
because manual scans are time-consuming and expensive –
and, therefore, are conducted infrequently. Also, with 802.11
hardware operating at separate frequencies (802.11a - 5Ghz
and 802.11b - 2.4Ghz), IT personnel must upgrade their
detection devices to accommodate multiple frequencies.
Moreover, scans are easy to elude, since a rogue AP can
easily be unplugged when the scan takes place.
Most vendors today go a step further. Rather than relying
on an employee equipped with a scanner, they enable IT to
initiate an enterprise-wide scan from a central location. This
is possible by using separate hardware devices [2][3][7][8]
(e.g., sensors) or using APs to detect beacons from
surrounding APs [2], and transmitting this information back
to a central management platform containing the wireless
network policy for analysis [1]. This method becomes costly,
considering that one must place sensors or APs throughout
the entire enterprise to monitor the air waves. This technique
is also completely impractical for the networks that do not
have wireless APs. Much like the drawback of the “walking
the halls” solution, each sensor/AP must operate at both
frequencies to be completely effective. Moreover, with
sensors deployed throughout the network, one still may not
be able to detect the rogue AP. The clever employee could
have used a directional antenna, or reduced the signal
strength to cover the small range within his/her office.
Another drawback of wireless-based solutions is that they
will falsely report the wireless network in the coffee house
next door as a rogue.