CTJammer: A Cross-Technology Reactive Jammer towards Unlicensed LTE

Abstract

Unlicensed LTE extends LTE into the unlicensed spectrum to relieve the burden of the rapidly growing mobile data traffic demand. The sharing usage of the unlicensed spectrum by unlicensed LTE and WiFi has drawn great attention in academia and industry. Previous work mainly focuses on the coexistence of those different technologies with the assumption that all the devices are benign. But we find that the usage of the unlicensed spectrum by unlicensed LTE may bring about more new problems if some devices are compromised. This paper first reveals that a low-cost COTS WiFi device can be used to attack unlicensed LTE devices, which is a cross-technology attack. The attacker can use the commercial WiFi device to conduct a smart and stealthy reactive jamming attack towards unlicensed LTE devices and block their wireless communication. To turn a commercial WiFi device into a cross-technology reactive jammer, we flexibly leverage WiFi chipsets to detect unlicensed LTE signals and combine multiple considerations to satisfy the real-time demand of reactive jamming. We implement a prototype jammer with a low-cost WiFi router, i.e., CTJammer, and our extensive experiments show that CTJammer can greatly jam the traffic of unlicensed LTE.