Cognitive Radio from Hell: Flipping Attack on Direct-Sequence Spread Spectrum

TL;DR

This paper introduces a novel, undetectable flipping attack on DSSS systems that can nullify channel capacity, discusses its feasibility, and proposes detection and mitigation strategies for secure communication.

Contribution

The paper presents the first detailed analysis of a flipping attack on DSSS, including detection methods and heuristics to improve error performance under attack.

Findings

Flipping attack can reduce channel capacity to zero.

Detection methods can identify the attack.

Heuristics improve error performance during attack.

Abstract

In this paper, we introduce a strong adversarial attack, referred to as the flipping attack, on Direct-Sequence Spread Spectrum (DSSS) systems. In this attack, the attacker, which is appropriately positioned between the transmitter and the receiver, instantaneously flips the transmitted symbols in the air at 50% rate, thereby driving the channel capacity to zero. Unlike the traditional jamming attack, this attack, when perfectly executed, cannot be detected at the receiver using signal-to-noise-ratio measurements. However, this attack necessitates the attacker to perfectly know the realizations of all the channels in the model. We first introduce the consequences of the flipping attack on narrowband frequency-flat channels, and subsequently discuss its feasibility in wideband frequency-selective channels. From the legitimate users' perspective, we present a method to detect this attack and also propose heuristics to improve the error-performance under the attack. We emphasize that future cyber-physical systems that employ DSSS should design transceivers to detect the proposed flipping attack, and then apply appropriate countermeasures.