[2026.03.04] Protecting wi-fi beacons from outsider forgeries

Abstract

All Wi-Fi networks periodically broadcast beacons to announce their presence to nearby clients. These beacons contain various properties of the network, including dynamic information to manage the behavior of clients. We first show that an adversary can forge beacons to carry out various known as well as novel attacks. Motivated by these attacks, we propose a scheme to authenticate beacon frames that is efficient and has low bandwidth overhead. We evaluate the security properties of this scheme, and discuss its current implementation in Linux. By collaborating with industry partners, our scheme also got incorporated into the draft 802.11 standard, increasing the chance of it being implemented by vendors.