Today, we rely heavily on the constant availability of wireless communication systems. As a result, wireless jamming continues to prevail as an imminent threat: Attackers can create deliberate radio interference to overshadow desired signals, leading to denial of service. Although the broadcast nature of radio signal propagation makes such an attack possible in the first place, it likewise poses a challenge for the attacker, preventing precise targeting of single devices. In particular, the jamming signal will likely not only reach the victim receiver but also other neighboring devices. In this work, we introduce spatial control of wireless jamming signals, granting a new degree of freedom to leverage for jamming attacks. Our novel strategy employs an environment-adaptive reconfigurable intelligent surface (RIS), exploiting multipath signal propagation to spatially focus jamming signals on particular victim devices. We investigate this effect through extensive experimentation and show that our approach can disable the wireless communication of a victim device while leaving neighbouring devices unaffected. In particular, we demonstrate complete denial-of-service of a Wi-Fi device while a second device located at a distance as close as 5 mm remains unaffected, sustaining wireless communication at a data rate of 60 Mbit/s. We also show that the attacker can change the attack target on-the-fly, dynamically selecting the device to be jammed.

翻译：当今社会高度依赖无线通信系统的持续可用性。因此，无线干扰始终构成紧迫威胁：攻击者可通过制造人为射频干扰来压制目标信号，导致服务中断。尽管无线电信号传播的广播特性使此类攻击成为可能，但这同样给攻击者带来挑战——难以精准锁定单个设备。具体而言，干扰信号不仅会作用于目标接收端，还可能波及邻近设备。本研究提出对无线干扰信号实施空域控制的新思路，为干扰攻击赋予全新自由度。我们创新性地采用环境自适应可重构智能表面（RIS）技术，利用多径信号传播特性将干扰信号空间聚焦于特定受害设备。通过大量实验验证，该方法可在不影响邻近设备的前提下，致使目标设备的无线通信失效。特别地，我们成功实现了对Wi-Fi设备的完全服务中断，而相距仅5毫米的另一设备仍可维持60 Mbit/s的无线数据通信速率。实验同时表明，攻击者可动态切换攻击目标，实时选择要干扰的设备。