arXiv subjects

Erik C. Rye

Publications and source records attributed to Erik C. Rye.

7 recordsLinked to original sources

arXiv2021

Follow the Scent: Defeating IPv6 Prefix Rotation Privacy

IPv6's large address space allows ample freedom for choosing and assigning addresses. To improve client privacy and resist IP-based tracking, standardized techniques leverage this large address space, including privacy extensions and provider prefix rotation. Ephemeral and dynamic IPv6 addresses confound not only tracking and traffic correlation attempts, but also traditional network measurements, logging, and defense mechanisms. We show that the intended anti-tracking capability of these widely deployed mechanisms is unwittingly subverted by edge routers using legacy IPv6 addressing schemes that embed unique identifiers. We develop measurement techniques that exploit these legacy devices to make tracking such moving IPv6 clients feasible by combining intelligent search space reduction with modern high-speed active probing. Via an Internet-wide measurement campaign, we discover more than 9M affected edge routers and approximately 13k /48 prefixes employing prefix rotation in hundreds of ASes worldwide. We mount a six-week campaign to characterize the size and dynamics of these deployed IPv6 rotation pools, and demonstrate via a case study the ability to remotely track client address movements over time. We responsibly disclosed our findings to equipment manufacturers, at least one of which subsequently changed their default addressing logic.

cs.NI↗

arXiv2020

Discovering the IPv6 Network Periphery

We consider the problem of discovering the IPv6 network periphery, i.e., the last hop router connecting endhosts in the IPv6 Internet. Finding the IPv6 periphery using active probing is challenging due to the IPv6 address space size, wide variety of provider addressing and subnetting schemes, and incomplete topology traces. As such, existing topology mapping systems can miss the large footprint of the IPv6 periphery, disadvantaging applications ranging from IPv6 census studies to geolocation and network resilience. We introduce "edgy," an approach to explicitly discover the IPv6 network periphery, and use it to find >~64M IPv6 periphery router addresses and >~87M links to these last hops -- several orders of magnitude more than in currently available IPv6 topologies. Further, only 0.2% of edgy's discovered addresses are known to existing IPv6 hitlists.

cs.NI↗

arXiv2019

Handoff All Your Privacy: A Review of Apple's Bluetooth Low Energy Continuity Protocol

We investigate Apple's Bluetooth Low Energy (BLE) Continuity protocol, designed to support interoperability and communication between iOS and macOS devices, and show that the price for this seamless experience is leakage of identifying information and behavioral data to passive adversaries. First, we reverse engineer numerous Continuity protocol message types and identify data fields that are transmitted unencrypted. We show that Continuity messages are broadcast over BLE in response to actions such as locking and unlocking a device's screen, copying and pasting information, making and accepting phone calls, and tapping the screen while it is unlocked. Laboratory experiments reveal a significant flaw in the most recent versions of macOS that defeats BLE Media Access Control (MAC) address randomization entirely by causing the public MAC address to be broadcast. We demonstrate that the format and content of Continuity messages can be used to fingerprint the type and Operating System (OS) version of a device, as well as behaviorally profile users. Finally, we show that predictable sequence numbers in these frames can allow an adversary to track Apple devices across space and time, defeating existing anti-tracking techniques such as MAC address randomization.

cs.NI↗

arXiv2019

Sundials in the Shade: An Internet-wide Perspective on ICMP Timestamps

ICMP timestamp request and response packets have been standardized for nearly 40 years, but have no modern practical application, having been superseded by NTP. However, ICMP timestamps are not deprecated, suggesting that while hosts must support them, little attention is paid to their implementation and use. In this work, we perform active measurements and find 2.2 million hosts on the Internet responding to ICMP timestamp requests from over 42,500 unique autonomous systems. We develop a methodology to classify timestamp responses, and find 13 distinct classes of behavior. Not only do these behaviors enable a new fingerprinting vector, some behaviors leak important information about the host e.g., OS, kernel version, and local timezone.

cs.NI↗

arXiv2019

EUI-64 Considered Harmful

This position paper considers the privacy and security implications of EUI-64-based IPv6 addresses. By encoding MAC addresses, EUI-64 addresses violate layers by exposing hardware identifiers in IPv6 addresses. The hypothetical threat of EUI-64 addresses is well-known, and the adoption of privacy extensions in operating systems (OSes) suggests this vulnerability has been mitigated. Instead, our work seeks to quantify the empirical existence of EUI-64 IPv6 addresses in today's Internet. By analyzing: i) traceroutes; ii) DNS records; and iii) mobile phone behaviors, we find surprisingly significant use of EUI-64. We characterize the origins and behaviors of these EUI-64 IPv6 addresses, and advocate for changes in provider IPv6 addressing policies.

cs.NI↗

arXiv2017

A Study of MAC Address Randomization in Mobile Devices and When it Fails

MAC address randomization is a privacy technique whereby mobile devices rotate through random hardware addresses in order to prevent observers from singling out their traffic or physical location from other nearby devices. Adoption of this technology, however, has been sporadic and varied across device manufacturers. In this paper, we present the first wide-scale study of MAC address randomization in the wild, including a detailed breakdown of different randomization techniques by operating system, manufacturer, and model of device. We then identify multiple flaws in these implementations which can be exploited to defeat randomization as performed by existing devices. First, we show that devices commonly make improper use of randomization by sending wireless frames with the true, global address when they should be using a randomized address. We move on to extend the passive identification techniques of Vanhoef et al. to effectively defeat randomization in ~96% of Android phones. Finally, we show a method that can be used to track 100% of devices using randomization, regardless of manufacturer, by exploiting a previously unknown flaw in the way existing wireless chipsets handle low-level control frames.

cs.CR↗

arXiv2016

The Neighbor Matrix: Generalizing the Degree Distribution

The newly introduced neighborhood matrix extends the power of adjacency and distance matrices to describe the topology of graphs. The adjacency matrix enumerates which pairs of vertices share an edge and it may be summarized by the degree sequence, a list of the adjacency matrix row sums. The distance matrix shows more information, namely the length of shortest paths between vertex pairs. We introduce and explore the neighborhood matrix, which we have found to be an analog to the distance matrix what the degree sequence is to the adjacency matrix. The neighbor matrix includes the degree sequence as its first column and the sequence of all other distances in the graph up to the graph's diameter, enumerating the number of neighbors each vertex has at every distance present in the graph. We prove this matrix to contain eleven oft-used graph statistics and topological descriptors. We also provide insight into two applications that show potential utility of the neighbor matrix in comparing graphs and identifying topologically significant vertices in a graph.

math.GM↗