Author: johnh

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Publications Technical Report

new technical report “When the Dike Breaks: Dissecting DNS Defenses During DDoS (extended)”

We released a new technical report “When the Dike Breaks: Dissecting DNS Defenses During DDoS (extended)”, ISI-TR-725, available at https://www.isi.edu/~johnh/PAPERS/Moura18a.pdf.

Moura18a Figure 6a, Answers received during a DDoS attack causing 100% packet loss with pre-loaded caches.

From the abstract:

The Internet’s Domain Name System (DNS) is a frequent target of Distributed Denial-of-Service (DDoS) attacks, but such attacks have had very different outcomes—some attacks have disabled major public websites, while the external effects of other attacks have been minimal. While on one hand the DNS protocol is a relatively simple, the system has many moving parts, with multiple levels of caching and retries and replicated servers. This paper uses controlled experiments to examine how these mechanisms affect DNS resilience and latency, exploring both the client side’s DNS user experience, and server-side traffic. We find that, for about about 30% of clients, caching is not effective. However, when caches are full they allow about half of clients to ride out server outages, and caching and retries allow up to half of the clients to tolerate DDoS attacks that result in 90% query loss, and almost all clients to tolerate attacks resulting in 50% packet loss. The cost of such attacks to clients are greater median latency. For servers, retries during DDoS attacks increase normal traffic up to 8x. Our findings about caching and retries can explain why some real-world DDoS cause service outages for users while other large attacks have minimal visible effects.

Datasets from this paper are available at no cost and are listed at https://ant.isi.edu/datasets/dns/#Moura18a_data.

 

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Presentations

new talk “Internet Outages: Reliablity and Security” from U. of Oregon Cybersecurity Day 2018

John Heidemann gave the talk “Internet Outages: Reliablity and Security” at the University of Oregon Cybersecurity Day in Eugene, Oregon on April 23, 2018.  Slides are available at https://www.isi.edu/~johnh/PAPERS/Heidemann18e.pdf.

Network outages as a security problem.

From the abstract:

The Internet is central to our lives, but we know astoundingly little about it. Even though many businesses and individuals depend on it, how reliable is the Internet? Do policies and practices make it better in some places than others?

Since 2006, we have been studying the public face of the Internet to answer these questions. We take regular censuses, probing the entire IPv4 Internet address space. For more than two years we have been observing Internet reliability through active probing with Trinocular outage detection, revealing the effects of the Internet due to natural disasters like Hurricanes from Sandy to Harvey and Maria, configuration errors that sometimes affect millions of customers, and political events where governments have intervened in Internet operation. This talk will describe how it is possible to observe Internet outages today and what they are beginning to say about the Internet and about the physical world.

This talk builds on research over the last decade in IPv4 censuses and outage detection and includes the work of many of my collaborators.

Data from this talk is all available; see links on the last slide.

Categories
Announcements Projects

new project “Interactive Internet Outages Visualization to Assess Disaster Recovery”

We are happy to announce a new project, Interactive Internet Outages Visualization to Assess Disaster Recovery.   This project is supporting the use of Internet outage measurements to help understand and recover from natural disasters. It will expand on the visualization of Internet outages found at https://ant.isi.edu/outage/world/.

This visualization was initially seeded by a Michael Keston research grant here at ISI, and the outage measurement techniques and ongoing data collection has been developed with the support of DHS (the LANDER-2007, LACREND, LACANIC, and Retro-future Bridge and Outages projects).

Categories
Publications Technical Report

new technical report “Back Out: End-to-end Inference of Common Points-of-Failure in the Internet (extended)”

We released a new technical report “Back Out: End-to-end Inference of Common Points-of-Failure in the Internet (extended)”, ISI-TR-724, available at https://www.isi.edu/~johnh/PAPERS/Heidemann18b.pdf.

From the abstract:

Clustering (from our event clustering algorithm) of 2014q3 outages from 172/8, showing 7 weeks including the 2014-08-27 Time Warner outage.

Internet reliability has many potential weaknesses: fiber rights-of-way at the physical layer, exchange-point congestion from DDOS at the network layer, settlement disputes between organizations at the financial layer, and government intervention the political layer. This paper shows that we can discover common points-of-failure at any of these layers by observing correlated failures. We use end-to-end observations from data-plane-level connectivity of edge hosts in the Internet. We identify correlations in connectivity: networks that usually fail and recover at the same time suggest common point-of-failure. We define two new algorithms to meet these goals. First, we define a computationally-efficient algorithm to create a linear ordering of blocks to make correlated failures apparent to a human analyst. Second, we develop an event-based clustering algorithm that directly networks with correlated failures, suggesting common points-of-failure. Our algorithms scale to real-world datasets of millions of networks and observations: linear ordering is O(n log n) time and event-based clustering parallelizes with Map/Reduce. We demonstrate them on three months of outages for 4 million /24 network prefixes, showing high recall (0.83 to 0.98) and precision (0.72 to 1.0) for blocks that respond. We also show that our algorithms generalize to identify correlations in anycast catchments and routing.

Datasets from this paper are available at no cost and are listed at https://ant.isi.edu/datasets/outage/, and we expect to release the software for this paper in the coming months (contact us if you are interested).

Categories
Announcements In-the-news

news story about measuring Internet outages

PCMag released a news story on January 3, 2018 about our measuring Internet outages, including discussion about the 2017 hurricanes like Irma, and our new worldwide outage browser.

Categories
Announcements Outages

new website for browsing Internet outages

We are happy to announce a new website at https://ant.isi.edu/outage/world/ that supports our Internet outage data collected from Trinocular.

The ANT Outage world browser, showing Hurricane Irma just after landfall in Florida in Sept. 2017.

Our website supports browsing more than two years of outage data, organized by geography and time.  The map is a google-maps-style world map, with circle on it at even intervals (every 0.5 to 2 degrees of latitude and longitude, depending on the zoom level).  Circle sizes show how many /24 network blocks are out in that location, while circle colors show the percentage of outages, from blue (only a few percent) to red (approaching 100%).

We hope that this website makes our outage data more accessible to researchers and the public.

The raw data underlying this website is available on request, see our outage dataset webpage.

The research is funded by the Department of Homeland Security (DHS) Cyber Security Division (through the LACREND and Retro-Future Bridge and Outages projects) and Michael Keston, a real estate entrepreneur and philanthropist (through the Michael Keston Endowment).  Michael Keston helped support this the initial version of this website, and DHS has supported our outage data collection and algorithm development.

The website was developed by Dominik Staros, ISI web developer and owner of Imagine Web Consulting, based on data collected by ISI researcher Yuri Pradkin. It builds on prior work by Pradkin, Heidemann and USC’s Lin Quan in ISI’s Analysis of Network Traffic Lab.

ISI has featured our new website on the ISI news page.

 

Categories
Announcements Projects

new project LACANIC

We are happy to announce a new project, LACANIC, the Los Angeles/Colorado Application and Network Information Community.

The LACANIC project’s goal is to develop datasets to improve Internet security and readability. We distribute these datasets through the DHS IMPACT program.

As part of this work we:

  • provide regular data collection to collect long-term, longitudinal data
  • curate datasets for special events
  • build websites and portals to help make data accessible to casual users
  • develop new measurement approaches

We provide several types of datasets:

  • anonymized packet headers and network flow data, often to document events like distributed denial-of-service (DDoS) attacks and regular traffic
  • Internet censuses and surveys for IPv4 to document address usage
  • Internet hitlists and histories, derived from IPv4 censuses, to support other topology studies
  • application data, like DNS and Internet-of-Things mapping, to document regular traffic and DDoS events
  • and we are developing other datasets

LACANIC allows us to continue some of the data collection we were doing as part of the LACREND project, as well as develop new methods and ways of sharing the data.

LACANIC is a joint effort of the ANT Lab involving USC/ISI (PI: John Heidemann) and Colorado State University (PI: Christos Papadopoulos).

We thank DHS’s Cyber Security Division for their continued support!

 

Categories
Publications Software releases Technical Report

new technical report “LDplayer: DNS Experimentation at Scale”

We released a new technical report “LDplayer: DNS Experimentation at Scale”, ISI-TR-722, available at https://www.isi.edu/publications/trpublic/pdfs/ISI-TR-722.pdf.

ldplayer_overviewFrom the abstract:

DNS has evolved over the last 20 years, improving in security and privacy and broadening the kinds of applications it supports. However, this evolution has been slowed by the large installed base with a wide range of implementations that are slow to change. Changes need to be carefully planned, and their impact is difficult to model due to DNS optimizations, caching, and distributed operation. We suggest that experimentation at scale is needed to evaluate changes and speed DNS evolution. This paper presents LDplayer, a configurable, general-purpose DNS testbed that enables DNS experiments to scale in several dimensions: many zones, multiple levels of DNS hierarchy, high query rates, and diverse query sources. LDplayer provides high fidelity experiments while meeting these requirements through its distributed DNS query replay system, methods to rebuild the relevant DNS hierarchy from traces, and efficient emulation of this hierarchy of limited hardware. We show that a single DNS server can correctly emulate multiple independent levels of the DNS hierarchy while providing correct responses as if they were independent. We validate that our system can replay a DNS root traffic with tiny error (+/- 8ms quartiles in query timing and +/- 0.1% difference in query rate). We show that our system can replay queries at 87k queries/s, more than twice of a normal DNS Root traffic rate, maxing out one CPU core used by our customized DNS traffic generator. LDplayer’s trace replay has the unique ability to evaluate important design questions with confidence that we capture the interplay of caching, timeouts, and resource constraints. As an example, we can demonstrate the memory requirements of a DNS root server with all traffic running over TCP, and we identified performance discontinuities in latency as a function of client RTT.

Software developed in this paper is available at https://ant.isi.edu/software/ldplayer/.

 

 

Categories
Papers Publications

new conference paper “Recursives in the Wild: Engineering Authoritative DNS Servers” in IMC 2017

The paper “Recursives in the Wild: Engineering Authoritative DNS Servers” will appear in the 2017 Internet Measurement Conference (IMC) on November 1-3, 2017 in London, United Kingdom.

Recursive DNS server selection of authoritatives, per continent. (Figure 4 from [Mueller17b].)
From the abstract:

In In Internet Domain Name System (DNS), services operate authoritative name servers that individuals query through recursive resolvers. Operators strive to provide reliability by operating multiple name servers (NS), each on a separate IP address, and by using IP anycast to allow NSes to provide service from many physical locations. To meet their goals of minimizing latency and balancing load across NSes and anycast, operators need to know how recursive resolvers select an NS, and how that interacts with their NS deployments. Prior work has shown some recursives search for low latency, while others pick an NS at random or round robin, but did not examine how prevalent each choice was. This paper provides the first analysis of how recursives select between name servers in the wild, and from that we provide guidance to operators how to engineer their name servers to reach their goals. We conclude that all NSes need to be equally strong and therefore we recommend to deploy IP anycast at every single authoritative.

All datasets used in this paper (but one) are available at https://ant.isi.edu/datasets/dns/index.html#recursives .

Categories
In-the-news Internet Outages

Evaluation of Hurricane Harvey’s Effects on the Internet’s Edge

On August 25, 2017 Hurricane Harvey made landfall in south Texas, causing widespread property damage, displacing more than 30,000 people, and costing more than 45 lives (as of 2017-09-01).

We sympathize with those were hurt by this disaster, and hope for swift recovery for the region.

We recently examined the effects of Hurricane Harvey on the area using Trinocular, our internet outage detection system.  Two key results:

Trinocular report on outages in Texas after Hurricane Harvey (on 2017-08-28t03:32Z)

We see that landfall was followed by widespread Internet outages in the Corpus Christi area, with 40% or more home networks dropping off the Internet.

We see that over the following days, network outages grew in the Houston area, with many networks dropping off the Internet. However, the fraction of networks lost in Houston was much smaller than in the Corpus Christi area.

More details are on our Hurricane Harvey web page.  We will update that page as we get more data in.

The dataset including Hurricane Harvey will be internet_outage_adaptive_a29all-20170702 and will be released in October 2017. Until the full data is released, we have a preliminary dataset through August 2017 available on request.