Demonstrated LLC-layer attack and defense strategies for wireless communication systems

In this work we demonstrate an over-the-air capability to exploit software weaknesses in the signal processing code implementing the physical and link layers of the OSI stack. Our test bed includes multiple nodes leveraging both GNU Radio and the Universal Software Radio Peripheral to demonstrate these attacks and corresponding defensive strategies. More specifically, we examine two duplex modem implementations, continuous wave and OFDM, and a link layer framing protocol vulnerable to buffer overflow attacks. We also discuss possible attacks against the network layer and above by exploiting a waveform utilizing the GNU Radio tunnel/tap block, which allows the waveform to directly interact with the Linux kernel´s network stack. Lastly, we consider several different defensive countermeasures, both active and passive, for detecting vulnerabilities in the waveform implementation and also detecting malicious activity in the system. These mitigation strategies should be used to protect communications systems from succumbing to similar classes of attacks.