The proliferation of wireless devices and the availability of wireless applications and services constantly raise new security concerns. Towards this direction, wireless intrusion detection systems (WIDS) can assist a great deal to proactively and reactively protect wireless networks, thus discouraging or repealing potential adversaries. In this paper we discuss the major wireless attack categories concerning IEEE 802.11 family networks and in particular the latest 802.11i security standard. We elaborate on 802.11 specific attacks and experimentally explore how these outbreaks can be effectively mitigated or thwarted by a properly designed WIDS. Among specially crafted software for both WIDS's modules as well as for attack generators, our test-bed embraces the majority of well known open source attack tools. Test results show that the proposed WIDS modules are able to effectively detect, either directly or indirectly, most attacks.