Access points are those points that has router to spread the radio signals of a network, these type of router have antenna(s) (smart or omni directional), the main aim of using these access point is to establish a wireless (Wi-Fi) network. Wireless networks are the rising network that are currently using by the organizations, for public places and for home usage.
Wi-Fi network has different vulnerabilities that can be exploit, as discussed before about wardriving. In wardriving you are searching for an access point to exploit but what if an access point is searching for you to exploit, strange but true and the term can be called an Inverse wardriving.
In inverse wardriving an attacker has to create a rogue access point, so the question is what is rogue access point? A rogue access point is a access point that has been installed without the permission of legitimate user (Administrator), rogue access point is a biggest threat for wireless network for large organization because it is open a way to launch man-in-the-middle attack, and it is a backdoor to enter into an Enterprise network.
It is a layer 2 attack that can be turn into layer 3 attack, here is the video demonstration that will better explain rogue access point. Thanks to the AirTightNetworks for the wonderful video.
There is another awesome video that explain rouge access point and available on securitytube.
I hope after this you have an idea about rogue access point, Airsnarf is a simple rogue wireless access point setup utility designed to demonstrate how a rogue AP can steal usernames and passwords from public wireless hotspots. Airsnarf was developed and released to demonstrate an inherent vulnerability of public 802.11b hotspots–snarfing usernames and passwords by confusing users with DNS and HTTP redirects from a competing AP. Follow the link to learn more about Airsnarf.