74 research outputs found
A uniformity-based approach to location privacy
No full textAs location-based services emerge, many people feel exposed to high privacy threats. Privacy protection is a major challenge for such services and related applications. A simple approach is perturbation, which adds an artificial noise to positions and returns an obfuscated measurement to the requester. Our main finding is that, unless the noise is chosen properly, these methods do not withstand attacks based on statistical analysis. In this paper, we propose UniLO, an obfuscation operator which offers high assurances on obfuscation uniformity, even in case of imprecise location measurement. We also deal with service differentiation by proposing three UniLO-based obfuscation algorithms that offer multiple contemporaneous levels of privacy. Finally, we experimentally prove the superiority of the proposed algorithms compared to the state-of-the-art solutions, both in terms of utility and resistance against inference attacks
Packet captures of login bruteforcing attacks against RabbitMQ MQTT broker via IEEE 802.11p and LTE links
No full textWe measured and analyzed the throughput of brute-force login attacks carried out against an MQTT broker server (namely RabbitMQ), to assess how efficient these attacks can be. The throughput was measured as the number of passwords per second. To perform the attacks, a command-line interface software called Ncrack was used. This tool can attempt to log in to a target service using a list of tentative credentials provided either via a file or directly in the command. As the password list, we used the widespread “RockYou” list, which is a well-known password dictionary file that contains millions of real-world passwords, originated from a data breach of the RockYou social application company in 2009. The attacks were conducted in various ways, simulating different scenarios. First, they were executed locally, simulating a case where a potential hacker has direct access to the server's local network. In this case, by varying the number of passwords in the file used for the attacks, it was observed that the throughput remained fairly constant and high as expected. Subsequently, other scenarios were analyzed. In particular, considering that the MQTT protocol is widely used in vehicular network contexts, it was decided to simulate the network performance of such environments using the tc tool available on Linux systems, and to conduct the attacks within this context. For this analysis, two widely used layer-2 protocols in vehicular networks were considered: IEEE 802.11p and LTE. The link characteristics of both protocols were simulated, recreating the scenario in which a potential attacker has access to one of these networks, and the attacks were carried out as in the previous case. However, unlike the first case, the total number of passwords was kept constant, while the packet loss ratio was varied, thus studying how the attack throughput changed accordingly. These simulations confirmed that the attacks through an IEEE 802.11p or LTE link are significantly less efficient compared to those carried out locally, with a throughput an order of magnitude lower
SmartFly: Fork-Free Super-Light Ethereum Classic Clients for the Internet of Things
No full textThe use of blockchains in the Internet of Things (IoT) is extremely promising, as it gives connected things the possibility to send and receive payments or tamper-proof data. In the last years, FlyClient has emerged in the literature as a technique for allowing resource-constrained devices to verify blockchain transactions. FlyClient is based on Merkle mountain ranges (MMRs) and probabilistic sampling, and it allows us to develop blockchain clients whose resource consumption is sublinear with the length of the chain. However, this comes at the cost of a change in the blockchain format, which leads to forks that are politically expensive, because they require 51% consensus. In this article, we explore the possibility of forkfree FlyClient verification methods that leverage smart contract programming. Smart contracts are able to add functionalities to a blockchain without needing forks. This raises several and novel technical issues that we address in the article. We show that fork-free sublinear clients are feasible without trusting the nodes that invoke the smart contract methods, as long as the smart
contract language provides a means to access the most recent block or its hash. As a proof of concept we propose SmartFly, a fork-free FlyClient verification system for the ethereum classic (ETC) blockchain. We measure several performance metrics of SmartFly, proving that it is succinct in storage and bandwidth consumption and economically bearable (about 38 euros per day to maintain the whole system)
Integration of privacy protection mechanisms in location-based services
No full textIn the next few years, we will see the upcoming of location-based services. Such LBSs will be extremely heterogeneous. Protecting the privacy of the users in such a situation requires flexible approaches. A single privacy protection mechanism is often insufficient. The contribution of this paper is two-fold. First we present LbSprint, a middleware architecture for location-based services which integrates different privacy mechanisms by means of the standard XACML language. The system administrator can configure and extend the set of such mechanisms. To the best of our knowledge, this is the first proposal of an architecture which integrates many privacy mechanisms in an extensible way. Secondly, we present practical optimizations which considerably improves the performance of the XACML policy evaluation process. © 2013 IEEE
The verifier bee: A path planner for drone-based secure location verification
No full textMany dependable systems rely implicitly on the integrity of the positions of their components. For example, let us consider a sensor network for pollution monitoring: it is sufficient that a hostile actor physically moves some sensors to completely disrupt the monitoring. In such scenarios, a key question is: how to securely verify the positions of devices? To answer this question, researchers proposed several solutions. However, these generally require several fixed stations (anchors) with trusted positions. In this paper, we explore the possibility to use the emerging drone technology in order to overcome the limitation of using several fixed anchors. In particular, our approach is to replace all the fixed anchors with a single drone that flies through a sequence of waypoints. At each waypoint, the drone “acts like” an anchor and securely verifies the positions of the devices. The main challenge here is to find a convenient path for the drone to do this. The problem presents novel aspects, thus existing path planning algorithms cannot be used. We present VerifierBee: a path planning algorithm that allows a drone to perform a secure location verification of a set of devices. VerifierBee finds a good approximation of the shortest path, and at the same time it respects a set of requirements about drone controllability, localization precision, and communication range
A low-cost UAV-based secure location verification method
No full textThe capability to verify positions reported by devices is called secure location verification. The majority of the proposed solutions entail the use of many fixed anchors often along with special hardware, e.g., ultra-wideband and ultrasonic transceivers. However, the deployment and maintenance costs of such solutions make them scarcely attractive. A cheaper alternative is to use mobile entities as trusted infrastructure. In particular, Unmanned Aerial Vehicles (UAVs) represent a promising approach. Indeed, recent studies used them to face the secure location verification problem. In this paper, we introduce a low-cost approach based on a swarm of UAVs and a common radio frequency protocol, e.g., WiFi. By experimental simulations, we show that by using only three UAVs our system detects more than 99% of the attacks against an adversary that falsifies its position of at least 20 m. We also consider an adversary capable of tracking UAVs posi-tions. The success probability of such an advanced adversary is smaller than 1% starting from a falsification distance larger than 35 m
Secure positioning with non-ideal distance bounding protocols
No full textDistance bounding protocols are secure protocols to determine an upper bound to the distance between two devices. These protocols have shown to be useful for many tasks, from proximity verification to secure positioning. Unfortunately, real distance bounding protocols hardly fulfill the claimed property. Attacks at the PHY layer may cause significant reductions on the estimated upper bound. These attacks can be mitigated, not eliminated, by changing the receiver architecture and the PHY layer. Every distance bounding protocol is thus non-ideal. In this paper, we study the impact of non-ideal distance bounding on the reliability of secure positioning techniques. We show that a reduction of 10 meters, which is possible against a real PHY layer, allows the adversary to falsify a position of 21 meters. We also propose two countermeasures to mitigate the problem, and then estimate their efficacy by simulations
HUMsim: A Privacy-Oriented Human Mobility Simulator
No full textLocation-based services rise high privacy concerns because they make it possible to collect and infer sensitive information from a person's positions and mobility traces. Many solutions have been proposed to safeguard the users' privacy, at least to a certain extent. However, they generally lacking convincing experimental validation with real human mobility traces. Large databases of real mobility traces are extremely expensive to build or buy. In this paper, we present HUMsim (Human Urban Mobility Simulator), a generator of synthetic but realistic human traces oriented to the experimental validation of privacy solutions. HUMsim generates trajectories that reflect possibly privacy-sensitive habits of people and that, at the same time, account for constraints deriving from a real map. We also validate the soundness of the produced traces by statistically comparing them to real human traces
On Designing Resilient Location-Privacy Obfuscators
No full textThe success of location-based services is growing together with the diffusion of GPS-equipped smart devices. As a consequence, privacy concerns are raising year by year. Location privacy is becoming a major interest in research and industry world, and many solutions have been proposed for it. One of the simplest and most flexible approaches is obfuscation, in which the precision of location data is artificially degraded before disclosing it. In this paper, we present an obfuscation approach capable of dealing with measurement imprecision, multiple levels of privacy, untrusted servers and adversarial knowledge of the map. We estimate its resistance against statistical-based deobfuscation attacks, and we improve it by means of three techniques, namely extreme vectors, enlarge-and-scale and hybrid vectors
An Analysis of Routing Attacks Against IOTA Cryptocurrency
No full textIOTA is a new type of distributed ledger designed for allowing fee-less and rate-scalable micropayments in Internet of Things applications. Security research on IOTA has focused mainly on attacks involving its cryptographic operations or its consensus algorithm. In this paper, we present a preliminary analysis of the IOTA security with respect to malicious Autonomous Systems (ASes), which can intercept IOTA connections by manipulating routing advertisements (BGP hijacking) or by naturally intercepting traffic. We make the simplifying assumption that the malicious AS can intercept routes between hosts without causing side effects, or without these side effects being noticed by the intercepted hosts. We identify three notable attacks that can lead to permanent money freeze, and to local or global interruptions of the consensus mechanisms. We then analyze the vulnerability of IOTA against malicious ASes on the real Internet topology, and we show that IOTA cryptocurrency is, at the time of writing, pretty susceptible of these attacks because quite centralized from the point of view of BGP routing. We then study the routing-level security of the next version of IOTA (post-coordicide), which has been proposed by the IOTA Foundations to make the cryptocurrency fully distributed
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