9:30am
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Welcome and Opening Remarks
Welcome and Opening Remarks
Speaker: Sharon Goldberg (Boston University)
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Sharon Goldberg
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9:40am
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TLS
Measuring Adoption of Security Additions to the HTTPS Ecosystem
Invited talk
Speaker: Quirin Scheitle (Technical University of Munich)
While the Transport Layer Security (TLS) protocol is typically used to authenticate servers, it also offers the possibility to use Client Certificates for to authenticate clients (CCA). We investigate the use of CCA based on two specific concerns:
First, CCA is prone to being used in a context that encodes personal data into client certificates, such as identifying persons, e.g. in voting systems or VPN applications.
Second, in versions prior to TLS1.3, the client certificate (as well as the server certificate) is being sent in clear text, permitting systematic and large-scale eavesdropping.
Based on these two concerns, we investigate the use of CCA at an ISP uplink. Besides confirming our two concerns by finding, e.g., person names in VPN certificates, we also identify the Apple Push Notification Service (APNs) to leverage TLS CCA to identify client devices. We consider this use highly critical as APNs is an integral part of all Apple operating systems, and APNs establishes a connection immediately upon connecting the device to a network. We show that these properties can be used by various attacker types to track devices (and hence, likely users) with great precision across the global Internet.
This work was published in 2017, with the TLS1.3 standardization still ongoing, and we aimed to emphasize the necessity of encrypting client certificates in the TLS handshake, which was adopted in the TLS1.3 standard. Based on work published at TMA’17 [1].
[1] Matthias Wachs, Quirin Scheitle, Georg Carle. 2017. Push Away Your Privacy: Precise User Tracking Based on TLS Client Certificate Authentication. In Proceedings of the 2017 Network Traffic Measurement and Analysis Conference (TMA ‘17)
Push Away Your Privacy: Precise User Tracking Based on TLS Client Certificate Authentication.
Talk
Matthias Wachs (Technical University of Munich (TUM)), Quirin Scheitle (Technical University of Munich (TUM)), and Georg Carle (Technical University of Munich (TUM)).
Infrastructure-as-a-Service (IaaS), more generally the “cloud,” changed the landscape of system operations on the Internet. Clouds’ elasticity allow operators to rapidly allocate and use resources as needed, from virtual machines, to storage, to IP addresses, which is what made clouds popular.
We show that the dynamic component paired with developments in trust-based ecosystems (e.g., TLS certificates) creates so far unknown attacks. We demonstrate that it is practical to allocate IP addresses to which stale DNS records point. Considering the ubiquity of domain validation in trust ecosystems, like TLS, an attacker can then obtain a valid and trusted certificate. The attacker can then impersonate the service, exploit residual trust for phishing, or might even distribute malicious code. Even worse, an aggressive attacker could succeed in less than 70 seconds, well below common time-to-live (TTL) for DNS. In turn, she could exploit normal service migrations to obtain a valid certificate, and, worse, she might not be bound by DNS records being (temporarily) stale.
We introduce a new authentication method for trust-based domain validation, like IETF’s automated certificate management environment (ACME), that mitigates staleness issues without incurring additional certificate requester effort by incorporating the existing trust of a name into the validation process.
Based on previously published work [1].
[1] Kevin Borgolte, Tobias Fiebig, Shuang Hao, Christopher Kruegel, Giovanni Vigna. February 2018. Cloud Strife: Mitigating the Security Risks of Domain-Validated Certificates. In Proceedings of the 25th Network and Distributed Systems Security Symposium (NDSS ‘18). Internet Society (ISOC). DOI: 10.14722/ndss.2018.23327. URL: https://doi.org/10.14722/ndss.2018.23327.
Cloud Strife: Mitigating the Security Risks of Domain-Validated Certificates.
Talk
Kevin Borgolte (UC Santa Barbara), Tobias Fiebig (TU Delft), Shuang Hao (UT Dallas), Christopher Kruegel (UC Santa Barbara), and Giovanni Vigna (UC Santa Barbara).
First standardized by the IETF in the 1990’s, SSL/TLS is the most widely-used
encryption protocol on the Internet. This makes it imperative to study its
usage across different platforms and applications to ensure proper usage and
robustness against attacks and vulnerabilities. While previous efforts have
focused on the usage of TLS in the desktop ecosystem, there have been no studies
of TLS usage by mobile apps at scale. In our study, we use anonymized data
collected by the Lumen mobile measurement app to analyze TLS usage by Android
apps in the wild. We analyze and fingerprint handshake messages to characterize
the TLS APIs and libraries that apps use, and evaluate their weaknesses. We
find that 84% of apps use the default TLS libraries provided by the operating
system, and the remaining apps use other TLS libraries for various reasons such
as using TLS extensions and features that are not supported by the Android TLS
libraries, some of which are also not standardized by the IETF. Our analysis
reveals the strengths and weaknesses of each approach, demonstrating that the
path to improving TLS security in the mobile platform is not straightforward.
Based on work published at:
Abbas Razaghpanah, Arian Akhavan Niaki, Narseo Vallina-Rodriguez,
Srikanth Sundaresan, Johanna Amann, and Phillipa Gill. 2017.
Studying TLS Usage in Android Apps. In Proceedings of CoNEXT ’17.
ACM, New York, NY, USA, 13 pages.
https://doi.org/10.1145/3143361.3143400
Studying TLS Usage in Android Apps.
Talk
Abbas Razaghpanah (Stony Brook University), Arian Akhavan Niaki (UMass-Amherst), Narseo Vallina-Rodriguez (IMDEA Networks Institute/ICSI), Srikanth Sundaresan (Facebook), Johanna Amann (ICSI/Corelight), and Philippa Gill (UMass-Amherst).
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Nick Sullivan
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11:10am
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Routing
ARTEMIS: Neutralizing BGP Hijacking within a Minute
Invited talk
Speaker: Alberto Dainotti (CAIDA)
In this talk, we will report on our recent article “Towards a Rigorous
Methodology for Measuring Adoption of RPKI Route Validation and
Filtering”, published in ACM Computer Communication Review, January 2018.
We will also present new results that arise from ongoing deployment of RPKI route origin validation (\eg default filtering at IXP route servers), and introduce a publicly available measurement platform for daily monitoring of the state of deployment.
Towards a Rigorous Methodology for Measuring Adoption of RPKI Route Validation and Filtering.
Talk
Andreas Reuter (Freie Universität Berlin), Randy Bush (IIJ / Dragon Research), Italo Cunha (UMFG), Ethan Katz-Bassett (Columbia University), Thomas C. Schmidt (HAW Hamburg), and Matthias Wählisch (Freie Universität Berlin).
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Nick Feamster
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12:00pm
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Lunch Break & Posters
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1:30pm
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Internet Infrastructure
Run, Walk, Crawl: Towards Dynamic Link Capacities
Invited talk
Speaker: Monia Ghobadi (Microsoft Research)
In this paper we consider the risks to Internet infrastructure in the US due to sea level rise. Our study is based on sea level incursion projections from the National Oceanic and Atmospheric Administration (NOAA) and Internet infrastructure deployment data from Internet Atlas. We align the data formats and assess risks in terms of the amount and type of infrastructure that will be under water in different time intervals over the next 100 years. We find that 4,067 miles of fiber conduit will be under water and 1,101 nodes (e.g., points of presence and colocation centers) will be surrounded by water in the next 15 years. We further quantify the risks of sea level rise by defining a metric that considers the combination of geographic scope and Internet infrastructure density. We use this metric to examine different regions and find that the New York, Miami, and Seattle metropolitan areas are at highest risk. We also quantify the risks to individual service provider infrastructures and find that Level3, Inteliquent, and AT&T are at highest risk. While it is difficult to project the impact of countermeasures such as sea walls, our results suggest the urgency of developing mitigation strategies and alternative infrastructure deployments.
Lights Out: Climate Change Risk to Internet Infrastructure.
Talk
Ramakrishnan Durairajan (University of Oregon), Carol Barford (University of Wisconsin - Madison), and Paul Barford (University of Wisconsin - Madison and comScore Inc.).
The Domain Name System (DNS) is used to map human-friendly hostnames
into network addresses that are in turn used to route traffic across
the Internet. DNS lookups are a precursor to much of the
communication that traverses the Internet. Therefore, the DNS is a
crucial service. In this talk, we will explore the robustness of
the DNS ecosystem. We will use the .com, .net and .org zone files
from the past nine years to study two basic kinds of robustness.
First, we will look at the robustness of individual zones (e.g., how
many nameservers does the zone leverage). Second, we will explore
how connected DNS zones are to one another. E.g., how many zones
end up sharing fate by using the same set of nameservers? In both
cases we find soft spots in the DNS ecosystem where robustness can
be improved—and, often, at little cost.
Comments On DNS Robustness.
Talk
Mark Allman (ICSI).
The Network Time Protocol (NTP) synchronizes time across computer systems over the Internet. Unfortunately, NTP is highly vulnerable to “time shifting attacks”, in which the attacker’s goal is to shift forward/backward the local time at an NTP client. This has severe implications for the correctness and safety of time-sensitive applications and for security mechanisms. Importantly, time shifting attacks on NTP are possible even if all NTP communications are encrypted and authenticated.
We present Chronos, a new NTP client that achieves good synchronization even in the presence of powerful man-in-the-middle attackers. Chronos is backwards compatible with legacy NTP and involves no changes whatsoever to NTP servers. In addition, Chronos is carefully engineered to minimize communication overhead so as to avoid overloading NTP servers.
We evaluate Chronos’ security and network efficiency guarantees via a combination of theoretical analyses and experiments with a prototype implementation. Our results indicate that to succeed in shifting time at a Chronos client by over $100$ms from the UTC, even a powerful man-in-the-middle attacker requires over $20$ years of effort in expectation. Based on work published at [1].
Preventing (Network) Time Travel with Chronos.
Talk
Neta Rozen Schiff (The Hebrew University of Jerusalem), Michael Schapira (The Hebrew University of Jerusalem), Danny Dolev (The Hebrew University of Jerusalem), and Omer Deutsch (The Hebrew University of Jerusalem).
TCP Congestion Signatures
Invited talk
Speaker: Amogh Dhamdhere (CAIDA)
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Phillippa Gill
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3:30pm
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Beverage Break
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3:50pm
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Traffic Engineering
Why (and How) Networks Should Run Themselves
Invited talk
Speaker: Nick Feamster (Princeton University)
Wide-area networks are expected to meet the competing objectives of high
performance and reliability in the presence of various operational constraints
and failures. Operators of such networks use traffic engineering (TE) to
improve network performance by routing traffic in desired ways. However,
existing approaches to TE, often, are unable to achieve both high performance
and reliability simultaneously.
This paper proposes SMORE, a semi-oblivious TE system based on the insight that
the set of forwarding paths has an out-sized impact on the quality of a TE
system. SMORE combines oblivious routing for static path selection with dynamic
rate adaptation. The paths used by SMORE are low-stretch (ensuring low
latency), diverse (ensuring robustness) and enable load-balancing naturally.
Dynamic rate adaptation ensures good performance as demands change without
incurring overheads related to churn. Through extensive evaluation, we show
that SMORE achieves near-optimal performance while ensuring good reliability in
practical settings. Based on work published at [1].
[1] Praveen Kumar, Yang Yuan, Chris Yu, Nate Foster, Robert Kleinberg,
Petr Lapukhov, Chiun Lin Lim, and Robert Soulé. 2018. Semi-Oblivious
Traffic Engineering: The Road Not Taken. In Proceedings of the 15th USENIX
Symposium on Networked Systems Design and Implementation (NSDI ‘18). USENIX
Association. 157–170.
Semi-Oblivious Traffic Engineering with SMORE.
Talk
Praveen Kumar (Cornell University), Yang Yuan (Cornell University), Chris Yu (CMU), Nate Foster (Cornell University), Robert Kleinberg (Cornell University), Petr Lapukhov (Facebook), Chiun Lin Lim (Facebook), and Robert Soulé (Università della Svizzera italiana).
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Brian Trammell
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4:30pm
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Anonymous Communications
In this talk, we will report initial results from the world’s first ISP-scale field trial of a refraction networking system. Refraction networking is a next-generation censorship circumvention approach that locates proxy functionality in the middle of the network, at participating ISPs or other network operators. We built a high-performance implementation of the TapDance refraction networking scheme and deployed it on four ISP uplinks with an aggregate bandwidth of 100 Gbps. Over one week of operation, our deployment served more than 50,000 real users. The experience demonstrates that TapDance can be practically realized at ISP scale with good performance and at a reasonable cost, potentially paving the way for long-term, large-scale deployments of TapDance or other refraction networking schemes in the future. We will close by discussing interactions between refraction networking and emerging web standards.
An ISP-Scale Deployment of TapDance.
Talk
Sergey Frolov (University of Colorado Boulder), Eric Wustrow (University of Colorado Boulder), Fred Douglas (Google), Will Scott (University of Michigan), Allison McDonald (University of Michigan), Benjamin VanderSloot (University of Michigan), Rod Hynes (Psiphon), Adam Kruger (Psiphon), Michalis Kallitsis (Merit Network), David G. Robinson (Upturn), Steve Schultze (Georgetown University Law Center), Nikita Borisov (University of Illinois), and J. Alex Halderman (University of Michigan).
Facing undesired traffic from the Tor anonymity network, online service providers discriminate against Tor users. In this study we characterize the extent of discrimination faced by Tor users and the nature of undesired traffic exiting from the Tor network – a task complicated by Tor’s need to maintain user anonymity. We leverage multiple independent data sources: email complaints sent to exit operators, commercial threat intelligence, webpage crawls via Tor, and privacy-sensitive measurements of our own Tor exit nodes to address this challenge. We develop methods for classifying email complaints sent to abuse contacts and an interactive crawler to find subtle forms of discrimination on the Web, and deploy our own exits in various configurations to understand which are prone to discrimination. We find that conservative exit policies are ineffective in preventing the blacklisting of exit relays. However, a majority of the attacks originating from Tor generate high traffic volume, suggesting the possibility of detection and prevention without violating Tor users’ privacy. Based on work published at [1].
[1]: Rachee Singh, Rishab Nithyanand, Sadia Afroz, Paul Pearce, Michael Carl Tschantz, Phillipa Gill, and Vern Paxson. 2017. Characterizing the Nature and Dynamics of Tor Exit Blocking. In 26th USENIX Security Symposium (USENIX Security 17). USENIX Association, Vancouver, BC, 325–341.
Characterizing the Nature and Dynamics of Tor Exit Blocking.
Talk
Rachee Singh (UMass Amherst), Rishab Nithyanand (Data & Society Research Institute), Sadia Afroz (UC Berkeley and International Computer Science Institute), Paul Pearce (UC Berkeley), Michael Carl Tschantz (International Computer Science Institute), Phillipa Gill (UMass Amherst), and Vern Paxson (UC Berkeley and International Computer Science Institute).
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Roya Ensafi
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5:20pm
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Beverage Break
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5:40pm
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Posters
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