Fragile Frames: Wi-Fi's Fraught Fight Against FragAttacks

In 2021, researchers disclosed vulnerabilities in the IEEE 802.11 standard related to frame fragmentation and aggregation, also known as the FragAttacks. In this paper, we design novel methods to measure whether real-world Wi-Fi networks are still affected by these vulnerabilities. Using our methods, we conducted surveys in three cities at two points in time (2023 and 2025) and found many networks still vulnerable. Concretely, we detected 52691 networks, found that in one city, 30% are still affected by one of the FragAttacks, and that for some ISPs, nearly all their routers are still affected. Motivated by this, we also present a design flaw in the 802.11 standard's defense against one of these vulnerabilities.