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This paper presents a radar target tracking framework for addressing main-beam range deception jamming attacks using random finite sets (RFSs). Our system handles false alarms and detections with false range information through multiple hypothesis tracking (MHT) to resolve data association uncertainties. We focus on range gate pull-off (RGPO) attacks, where the attacker adds positive delays to the radar pulse, thereby mimicking the target trajectory while appearing at a larger distance from the radar. The proposed framework incorporates knowledge about the spatial behavior of the attack into the assumed RFS clutter model and uses only position information without relying on additional signal features. We present an adaptive solution that estimates the jammer-induced biases to improve tracking accuracy as well as a simpler non-adaptive version that performs well when accurate priors on the jamming range are available. Furthermore, an expression for RGPO attack detection is derived, where the adaptive solution offers superior performance. The presented strategies provide tracking resilience against multiple RGPO attacks in terms of position estimation accuracy and jamming detection without degrading tracking performance in the absence of jamming., Comment: 12 pages, 7 figures

In this work, we present Dyna-5G, a dynamic, self-organizing 5G New Radio (5G-NR) network designed for massive Machine-to-Machine (M2M) networks. Traditional 5G NR networks, characterized by their centralized architecture, face challenges in supporting applications that require dynamic, decentralized communication, such as autonomous vehicles and drone swarms for emergency responses. These scenarios often suffer from the centralized model's single point of failure, undermining the reliability required in critical and fully autonomous applications. Dyna-5G addresses these challenges by allowing each device in the network to function as either part of the Radio Access Network (RAN) and Core Network, or as User Equipment (UE), thus maintaining network functionality even when conventional infrastructure components are compromised. Dyna-5G has built-in mechanisms carefully designed specifically for M2M networks, such as failure-recovery and ad-hoc entry and exit. We demonstrate the performance and feasibility of Dyna-5G using a custom-built testbed that simulates real-world missions, demonstrating our network's robustness, adaptability, and failure recovery capabilities. The results indicate that our entire 5G network model can fully re-organize in 6 seconds at maximum, without compromising the mission.

Short Message Service (SMS) remains one of the most popular communication channels since its introduction in 2G cellular networks. In this paper, we demonstrate that merely receiving silent SMS messages regularly opens a stealthy side-channel that allows other regular network users to infer the whereabouts of the SMS recipient. The core idea is that receiving an SMS inevitably generates Delivery Reports whose reception bestows a timing attack vector at the sender. We conducted experiments across various countries, operators, and devices to show that an attacker can deduce the location of an SMS recipient by analyzing timing measurements from typical receiver locations. Our results show that, after training an ML model, the SMS sender can accurately determine multiple locations of the recipient. For example, our model achieves up to 96% accuracy for locations across different countries, and 86% for two locations within Belgium. Due to the way cellular networks are designed, it is difficult to prevent Delivery Reports from being returned to the originator making it challenging to thwart this covert attack without making fundamental changes to the network architecture.

Zero-click attacks require no user interaction and typically exploit zero-day (i.e., unpatched) vulnerabilities in instant chat applications (such as WhatsApp and iMessage) to gain root access to the victim's smartphone and exfiltrate sensitive data. In this paper, we report our experiences in attempting to secure smartphones against zero-click attacks. We approached the problem by first enumerating several properties we believed were necessary to prevent zero-click attacks against smartphones. Then, we created a security design that satisfies all the identified properties, and attempted to build it using off-the-shelf components. Our key idea was to shift the attack surface from the user's smartphone to a sandboxed virtual smartphone ecosystem where each chat application runs in isolation. Our performance and usability evaluations of the system we built highlighted several shortcomings and the fundamental challenges in securing modern smartphones against zero-click attacks. In this experience report, we discuss the lessons we learned, and share insights on the missing components necessary to achieve foolproof security against zero-click attacks for modern mobile devices.

Civilian-GNSS is vulnerable to signal spoofing attacks, and countermeasures based on cryptographic authentication are being proposed to protect against these attacks. Both Galileo and GPS are currently testing broadcast authentication techniques based on the delayed key disclosure to validate the integrity of navigation messages. These authentication mechanisms have proven secure against record now and replay later attacks, as navigation messages become invalid after keys are released. This work analyzes the security guarantees of cryptographically protected GNSS signals and shows the possibility of spoofing a receiver to an arbitrary location without breaking any cryptographic operation. In contrast to prior work, we demonstrate the ability of an attacker to receive signals close to the victim receiver and generate spoofing signals for a different target location without modifying the navigation message contents. Our strategy exploits the essential common reception and transmission time method used to estimate pseudorange in GNSS receivers, thereby rendering any cryptographic authentication useless. We evaluate our attack on a commercial receiver (ublox M9N) and a software-defined GNSS receiver (GNSS-SDR) using a combination of open-source tools, commercial GNSS signal generators, and software-defined radio hardware platforms. Our results show that it is possible to spoof a victim receiver to locations around 4000 km away from the true location without requiring any high-speed communication networks or modifying the message contents. Through this work, we further highlight the fundamental limitations in securing a broadcast signaling-based localization system even if all communications are cryptographically protected.

Zigbee is an energy-efficient wireless IoT protocol that is increasingly being deployed in smart home settings. In this work, we analyze the privacy guarantees of Zigbee protocol. Specifically, we present ZLeaks, a tool that passively identifies in-home devices or events from the encrypted Zigbee traffic by 1) inferring a single application layer (APL) command in the event's traffic, and 2) exploiting the device's periodic reporting pattern and interval. This enables an attacker to infer user's habits or determine if the smart home is vulnerable to unauthorized entry. We evaluated ZLeaks' efficacy on 19 unique Zigbee devices across several categories and 5 popular smart hubs in three different scenarios; controlled RF shield, living smart-home IoT lab, and third-party Zigbee captures. We were able to i) identify unknown events and devices (without a-priori device signatures) using command inference approach with 83.6% accuracy, ii) automatically extract device's reporting signatures, iii) determine known devices using the reporting signatures with 99.8% accuracy, and iv) identify APL commands in a public capture with 91.2% accuracy. In short, we highlight the trade-off between designing a low-power, low-cost wireless network and achieving privacy guarantees. We have also released ZLeaks tool for the benefit of the research community., Comment: An updated version of the authors' previous submission (arXiv:2107.10830). It has been accepted at the 20th International Conference on Applied Cryptography and Network Security, ACNS 2022

It is well-known that GPS is vulnerable to signal spoofing attacks. Although several spoofing detection techniques exist, they are incapable of mitigation and recovery from stealthy attackers. In this work, we present SemperFi, a single antenna GPS receiver capable of tracking legitimate GPS satellite signals and estimating the true location even during a spoofing attack. The main challenge in building SemperFi is, unlike most wireless systems where \emph{the data} contained in the wireless signals is important, GPS relies on the time of arrival (ToA) of satellite signals. SemperFi is capable of distinguishing spoofing signals and recovering legitimate GPS signals that are even completely overshadowed by a strong adversary. We exploit the short-term stability of inertial sensors to identify the spoofing signal and extend the successive interference cancellation algorithm to preserve the legitimate signal's ToA. We implement SemperFi in GNSS-SDR, an open-source software-defined GNSS receiver, and evaluate its performance using UAV simulators, real drones, a variety of real-world GPS datasets, and various embedded platforms. Our evaluation results indicate that in many scenarios, SemperFi can identify adversarial peaks by executing flight patterns that are less than 50 m long and recover the true location within 10 seconds (Jetson Xavier). We show that our receiver is secure against stealthy attackers who exploit inertial sensor errors and execute seamless takeover attacks. We design SemperFi as a pluggable module capable of generating a spoofer-free GPS signal for processing on any commercial-off-the-shelf GPS receiver available today. Finally, we release our implementation to the community for usage and further research.

Low-power wide area networks (LPWANs), such as LoRa, are fast emerging as the preferred networking technology for large-scale Internet of Things deployments (e.g., smart cities). Due to long communication range and ultra low power consumption, LPWAN-enabled sensors are today being deployed in a variety of application scenarios where sensitive information is wirelessly transmitted. In this work, we study the privacy guarantees of LPWANs, in particular LoRa. We show that, although the event-based duty cycling of radio communication, i.e., transmission of radio signals only when an event occurs, saves power, it inherently leaks information. This information leakage is independent of the implemented crypto primitives. We identify two types of information leakage and show that it is hard to completely prevent leakage without incurring significant additional communication and computation costs.

Location information is critical to a wide-variety of navigation and tracking applications. Today, GPS is the de-facto outdoor localization system but has been shown to be vulnerable to signal spoofing attacks. Inertial Navigation Systems (INS) are emerging as a popular complementary system, especially in road transportation systems as they enable improved navigation and tracking as well as offer resilience to wireless signals spoofing, and jamming attacks. In this paper, we evaluate the security guarantees of INS-aided GPS tracking and navigation for road transportation systems. We consider an adversary required to travel from a source location to a destination, and monitored by a INS-aided GPS system. The goal of the adversary is to travel to alternate locations without being detected. We developed and evaluated algorithms that achieve such goal, providing the adversary significant latitude. Our algorithms build a graph model for a given road network and enable us to derive potential destinations an attacker can reach without raising alarms even with the INS-aided GPS tracking and navigation system. The algorithms render the gyroscope and accelerometer sensors useless as they generate road trajectories indistinguishable from plausible paths (both in terms of turn angles and roads curvature). We also designed, built, and demonstrated that the magnetometer can be actively spoofed using a combination of carefully controlled coils. We implemented and evaluated the impact of the attack using both real-world and simulated driving traces in more than 10 cities located around the world. Our evaluations show that it is possible for an attacker to reach destinations that are as far as 30 km away from the true destination without being detected. We also show that it is possible for the adversary to reach almost 60-80% of possible points within the target region in some cities.

Multicarrier phase-based ranging is fast emerging as a cost-optimized solution for a wide variety of proximity-based applications due to its low power requirement, low hardware complexity and compatibility with existing standards such as ZigBee and 6LoWPAN. Given potentially critical nature of the applications in which phase-based ranging can be deployed (e.g., access control, asset tracking), it is important to evaluate its security guarantees. Therefore, in this work, we investigate the security of multicarrier phase-based ranging systems and specifically focus on distance decreasing relay attacks that have proven detrimental to the security of proximity-based access control systems (e.g., vehicular passive keyless entry and start systems). We show that phase-based ranging, as well as its implementations, are vulnerable to a variety of distance reduction attacks. We describe different attack realizations and verify their feasibility by simulations and experiments on a commercial ranging system. Specifically, we successfully reduced the estimated range to less than 3 m even though the devices were more than 50 m apart. We discuss possible countermeasures against such attacks and illustrate their limitations, therefore demonstrating that phase-based ranging cannot be fully secured against distance decreasing attacks., Comment: 14 pages

The Location Service (LCS) proposed by the telecommunication industry is an architecture that allows the location of mobile devices to be accessed in various applications. We explore the use of LCS in location-enhanced server authentication, which traditionally relies on certificates. Given recent incidents involving certificate authorities, various techniques to strengthen server authentication were proposed. They focus on improving the certificate validation process, such as pinning, revocation, or multi-path probing. In this paper, we propose using the server's geographic location as a second factor of its authenticity. Our solution, SALVE, achieves location-based server authentication by using secure DNS resolution and by leveraging LCS for location measurements. We develop a TLS extension that enables the client to verify the server's location in addition to its certificate. Successful server authentication therefore requires a valid certificate and the server's presence at a legitimate geographic location, e.g., on the premises of a data center. SALVE prevents server impersonation by remote adversaries with mis-issued certificates or stolen private keys of the legitimate server. We develop a prototype implementation and our evaluation in real-world settings shows that it incurs minimal impact to the average server throughput. Our solution is backward compatible and can be integrated with existing approaches for improving server authentication in TLS., Comment: 14 pages. This paper will be presented at the 22nd ACM International Conference on Mobile Computing and Networking (MobiCom 2016). Related paper: https://eprint.iacr.org/2015/230

Global Positioning System (GPS) is used ubiquitously in a wide variety of applications ranging from navigation and tracking to modern smart grids and communication networks. However, it has been demonstrated that modern GPS receivers are vulnerable to signal spoofing attacks. For example, today it is possible to change the course of a ship or force a drone to land in an hostile area by simply spoofing GPS signals. Several countermeasures have been proposed in the past to detect GPS spoofing attacks. These countermeasures offer protection only against naive attackers. They are incapable of detecting strong attackers such as those capable of seamlessly taking over a GPS receiver, which is currently receiving legitimate satellite signals, and spoofing them to an arbitrary location. Also, there is no hardware platform that can be used to compare and evaluate the effectiveness of existing countermeasures in real-world scenarios. In this work, we present SPREE, which is, to the best of our knowledge, the first GPS receiver capable of detecting all spoofing attacks described in literature. Our novel spoofing detection technique called auxiliary peak tracking enables detection of even a strong attacker capable of executing the seamless takeover attack. We implement and evaluate our receiver against three different sets of GPS signal traces and show that SPREE constrains even a strong attacker (capable of seamless takeover attack) from spoofing the receiver to a location not more than 1 km away from its true location. This is a significant improvement over modern GPS receivers that can be spoofed to any arbitrary location. Finally, we release our implementation and datasets to the community for further research and development.

Side channels remain a challenge to information flow control and security in modern computing platforms. Resource partitioning techniques that minimise the number of shared resources among processes are often used to address this challenge. In this work, we focus on multi-core platforms and we demonstrate that even seemingly strong isolation techniques based on dedicated cores and memory can be circumvented through the use of thermal side channels. Specifically, we show that the processor core temperature can be used both as a side channel as well as a covert communication channel even when the system implements strong spatial and temporal partitioning. Our experiments on an x86-based platform demonstrate covert thermal channels that achieve up to 12.5 bps and a weak side channel that can detect processes executed on neighbouring cores. This work therefore shows a limitation in the isolation that can be achieved on existing multi-core systems., Comment: 15 pages, 9 figures

A distance bounding system guarantees an upper bound on the physical distance between a verifier and a prover. However, in contrast to a conventional wireless communication system, distance bounding systems introduce tight requirements on the processing delay at the prover and require high distance measurement precision making their practical realization challenging. Prior proposals of distance bounding systems focused primarily on building provers with minimal processing delays but did not consider the power limitations of provers and verifiers. However, in a wide range of applications (e.g., physical access control), provers are expected to be fully or semi-passive introducing additional constraints on the design and implementation of distance bounding systems. In this work, we propose a new physical layer scheme for distance bounding and leverage this scheme to implement a distance bounding system with a low-power prover. Our physical layer combines frequency modulated continuous wave (FMCW) and backscatter communication. The use of backscatter communication enables low power consumption at the prover which is critical for a number of distance bounding applications. By using the FMCW-based physical layer, we further decouple the physical distance estimation from the processing delay at the prover, thereby enabling the realization of the majority of distance bounding protocols developed in prior art. We evaluate our system under various attack scenarios and show that it offers strong security guarantees against distance, mafia and terrorist frauds. Additionally, we validate the communication and distance measurement characteristics of our system through simulations and experiments and show that it is well suited for short-range physical access control and payment applications., Comment: 14 pages