Abusing Wi-Fi Beacons and Detecting & Preventing Attacks

All Wi-Fi networks periodically broadcast beacons to announce their presence. These beacons are not authenticated and can be spoofed by an adversary, but it’s unclear what risks this poses in practice.

In this webcast, we discuss what kinds of attacks are possible by spoofing Wi-Fi beacons. For example, we show how an adversary can reduce the throughput of nearby devices, lower the transmission power of clients, and we show how spoofing beacons can facilitate advanced man-in-the-middle attacks.

In the second part of the webcast, we describe a scheme to protect Wi-Fi beacons. This scheme has been standardized as part of the (draft) IEEE 802.11 standard. We give a high-level explanation of our scheme, and we give a demo of its implementation in Linux.