Tag: DNS

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DNS Internet Papers Publications Uncategorized

new paper “Defending Root DNS Servers Against DDoS Using Layered Defenses” at COMSNETS 2023 (best paper!)

Table II from [Rizvi23a] shows the performance of each individual filter, with near-best results in bold. This table shows that one filter covers all cases, but together in DDIDD they provide very tood defense.

Our paper titled “Defending Root DNS Servers Against DDoS Using Layered Defenses” will appear at COMSNETS 2023 in January 2023. In this work, by ASM Rizvi, Jelena Mirkovic, John Heidemann, Wes Hardaker, and Robert Story, we design an automated system named DDIDD with multiple filters to handle an ongoing DDoS attack on a DNS root server. We evaluated ten real-world attack events on B-root and showed DDIDD could successfully mitigate these attack events. We released the datasets for these attack events on our dataset webpage (dataset names starting with B_Root_Anomaly).

Update in January: we are happy to announce that this paper was awarded Best Paper for COMSNETS 2023! Thanks for the recognition.

Table II from [Rizvi23a] shows the performance of each individual filter, with near-best results in bold. This table shows that one filter covers all cases, but together in DDIDD they provide very tood defense.

From the abstract:

Distributed Denial-of-Service (DDoS) attacks exhaust resources, leaving a server unavailable to legitimate clients. The Domain Name System (DNS) is a frequent target of DDoS attacks. Since DNS is a critical infrastructure service, protecting it from DoS is imperative. Many prior approaches have focused on specific filters or anti-spoofing techniques to protect generic services. DNS root nameservers are more challenging to protect, since they use fixed IP addresses, serve very diverse clients and requests, receive predominantly UDP traffic that can be spoofed, and must guarantee high quality of service. In this paper we propose a layered DDoS defense for DNS root nameservers. Our defense uses a library of defensive filters, which can be optimized for different attack types, with different levels of selectivity. We further propose a method that automatically and continuously evaluates and selects the best combination of filters throughout the attack. We show that this layered defense approach provides exceptional protection against all attack types using traces of real attacks from a DNS root nameserver. Our automated system can select the best defense within seconds and quickly reduce the traffic to the server within a manageable range while keeping collateral damage lower than 2%. We can handle millions of filtering rules without noticeable operational overhead.

This work is partially supported by the National Science
Foundation (grant NSF OAC-1739034) and DHS HSARPA
Cyber Security Division (grant SHQDC-17-R-B0004-TTA.02-
0006-I), in collaboration with NWO.

A screen capture of the presentation of the best paper award.

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Uncategorized

USC/Viterbi and ISI news about “Anycast Agility” paper

The canonical hacker in the hoodie, testifying to serious security work.

USC Viterbi and ISI both posted a news article about our paper “Anycast Agility: Network Playbooks to Fight DDoS”.

Please see our blog entry for the abstract and the full technical paper for the real details, but their posts are very accessible. And with the hacker in the hoodie, you know it’s serious :-)

The canonical hacker in the hoodie, testifying to serious security work.
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new paper “Differences in Monitoring the DNS Root Over IPv4 and IPv6” to appear at the IEEE National Symposium for NSF REU Research in Data Science, Systems, and Security

Figure 9 from [Saluja22a], showing fraction of query failures in RIPE Atlas after we remove observers that are islands (unable to reach any of the 13 DNS root identifiers). Blue is IPv4, red is IPv6, with data for each of the 13 DNS root identifiers. We believe this data is a better representation of what people expect to see than Atlas results that include these "broken" observers.

On December 15, 2022, Tarang Saluja will present the paper “Differences in Monitoring the DNS Root Over IPv4 and IPv6” (by Tarang Saluja, John Heidemann, and Yuri Pradkin) at the IEEE National Symposium for NSF REU Research in Data Science, Systems, and Security.

From the abstract:

Figure 9 from [Saluja22a], showing fraction of query failures in RIPE Atlas after we remove observers that are islands (unable to reach any of the 13 DNS root identifiers). Blue is IPv4, red is IPv6, with data for each of the 13 DNS root identifiers. We believe this data is a better representation of what people expect to see than Atlas results that include these “broken” observers.

The Domain Name System (DNS) is an essential service for the Internet which maps host names to IP addresses. The DNS Root Sever System operates the top of this namespace. RIPE Atlas observes DNS from more than 11k vantage points (VPs) around the world, reporting the reliability of the DNS Root Server System in DNSmon. DNSmon shows that loss rates for queries to the DNS Root are nearly 10% for IPv6, much higher than the approximately 2% loss seen for IPv4. Although IPv6 is “new,” as an operational protocol available to a third of Internet users, it ought to be just as reliable as IPv4. We examine this difference at a finer granularity by investigating loss at individual VPs. We confirm that specific VPs are the source of this difference and identify two root causes: VP islands with routing problems at the edge which leave them unable to access IPv6 outside their LAN, and VP peninsulas which indicate routing problems in the core of the network. These problems account for most of the loss and nearly all of the difference between IPv4 and IPv6 query loss rates. Islands account for most of the loss (half of IPv4 failures and 5/6ths of IPv6 failures), and we suggest these measurement devices should be filtered out to get a more accurate picture of loss rates. Peninsulas account for the main differences between root identifiers, suggesting routing disagreements root operators need to address. We believe that filtering out both of these known problems provides a better measure of underlying network anomalies and loss and will result in more actionable alerts.

Original data from this paper is available from RIPE Atlas (measurement ids are in the paper). We are publishing new results daily on our website (from the RIPE data).

This work was done while Tarang was on his Summer 2022 undergraduate research internship at USC/ISI, with support from NSF grant 2051101 (PI: Jelena Mirkovich). John Heidemann and Yuri Pradkin’s work is supported by NSF through the EIEIO project (CNS-2007106). We thank Guillermo Baltra for his work on islands and peninsulas, as seen in his arXiv report.

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Outages Presentations Publications Uncategorized

new poster “Internet Outage Detection Using Passive Analysis” at ACM IMC 2022

Asma Enayet will present her poster “Internet Outage Detection Using Passive Analysis” by Asma Enayet and John Heidemann at ACM Internet Measurement Conference, Nice, France from October 25-27th, 2022.

We expect the ACM poster abstract (without the poster) to appear at https://doi.org/10.1145/3517745.3563032 in October 2022.

We are making a report available now with the poster abstract and poster at https://doi.org/10.48550/arXiv.2209.13767 as a pre-print.

From the abstract:

Outages from natural disasters, political events, software or hardware issues, and human error place a huge cost on e-commerce ($66k per minute at Amazon). While several existing systems detect Internet outages, these systems are often too inflexible, with fixed parameters across the whole internet with CUSUM-like change detection. We instead propose a system using passive data, to cover both IPv4 and IPv6, customizing parameters for each block to optimize the performance of our Bayesian inference model. Our poster describes our three contributions: First, we show how customizing parameters allows us often to detect outages that are at both fine timescales (5 minutes) and fine spatial resolutions (/24 IPv4 and /48 IPv6 blocks). Our second contribution is to show that, by tuning parameters differently for different blocks, we can scale back temporal precision to cover more challenging blocks. Finally, we show our approach extends to IPv6 and provides the first reports of IPv6 outages.

IPv6 Coverage: our source of passive data (B-Root) is incomplete, but it provides similar coverage in both IPv4 and IPv6.
IPv6 Outages: Outage rate for IPv6 (12%) is greater than for IPv4 (5.5%) —IPv6 reliability can improve.

This work was supported by NSF grant CNS-2007106 (EIEIO).

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congratulations to Tarang Saluja for his summer undergraduate research internship

Tarang Saluja completed his summer undergraduate research internship at ISI this summer, working with John Heidemann and Yuri Pradkin on his project “Differences in Monitoring the DNS Root Over IPv4 and IPv6″.

In his project, Tarang examined RIPE Atlas’s DNSmon, a measurement system that monitors the Root Server System. DNSmon examines both IPv4 and IPv6, and its IPv6 reports show query loss rates that are consistently higher than IPv4, often 4-6% IPv6 loss vs. no or 2% IPv4 loss. Prior results by researchers at RIPE suggested these differences were due to problems at specific Atlas Vantage Points (VPs, also called Atlas Probes).

Tarang Saluja describing his research to an ISI researcher, at the ISI REU Poster Session on 2022-08-01.

Building on the Guillero Baltra’s studies of partial connectivity in the Internet, Tarang classified Atlas VPs with problems as islands and peninsulas. Islands think they are on IPv6, but cannot reach any of the 13 Root DNS “letters” over IPv6, indicating that the VP has a local network configuration problem. Peninsulas can reach some letters, but not others, indicating a routing problem somewhere in the core of the Internet.

Tarang’s work is important because these observations allow lead to potential solutions. Islands suggest VPs that do not support IPv6 and so should not be used for monitoring. Peninsulas point to IPv6 routing problems that need to be addressed by ISPs. Setting VPs with these problems aside provides a more accurate view of what IPv6 should be, and allows us to use DNSmon to detect more subtle problems. Together, his work points the way to improving IPv6 for everyone and improving Root DNS access over IPv6.

Tarang’s work was part of the ISI Research Experiences for Undergraduates program at USC/ISI. We thank Jelena Mirkovic (PI) for coordinating another year of this great program, and NSF for support through award #2051101.

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new paper “Old but Gold: Prospecting TCP to Engineer and Live Monitor DNS Anycast” Awarded Best Paper at the Passive and Active Measurement Conference

On March 29, 2022 the paper “Old but Gold: Prospecting TCP to Engineer and Live Monitor DNS Anycast” by Giovane C. M. Moura, John Heidemann, Wes Hardaker, Pithayuth Charnsethikul, Jeroen Bulten, João M. Ceron, and Cristian Hesselman appeared that the 2022 Passive and Active Measurement Conference. We’re happy that it was awarded Best Paper for this year’s conference!

From the abstract:

Google latency for .nl before (left red area) and after (middle green area) DNS polarization was corrected. Polarization was detected with ENTRADA using the work from this paper.

DNS latency is a concern for many service operators: CDNs exist to reduce service latency to end-users but must rely on global DNS for reachability and load-balancing. Today, DNS latency is monitored by active probing from distributed platforms like RIPE Atlas, with Verfploeter, or with commercial services. While Atlas coverage is wide, its 10k sites see only a fraction of the Internet. In this paper we show that passive observation of TCP handshakes can measure live DNS latency, continuously, providing good coverage of current clients of the service. Estimating RTT from TCP is an old idea, but its application to DNS has not previously been studied carefully. We show that there is sufficient TCP DNS traffic today to provide good operational coverage (particularly of IPv6), and very good temporal coverage (better than existing approaches), enabling near-real time evaluation of DNS latency from real clients. We also show that DNS servers can optionally solicit TCP to broaden coverage. We quantify coverage and show that estimates of DNS latency from TCP is consistent with UDP latency. Our approach finds previously unknown, real problems: DNS polarization is a new problem where a hypergiant sends global traffic to one anycast site rather than taking advantage of the global anycast deployment. Correcting polarization in Google DNS cut its latency from 100ms to 10ms; and from Microsoft Azure cut latency from 90ms to 20ms. We also show other instances of routing problems that add 100-200ms latency. Finally, real-time use of our approach for a European country-level domain has helped detect and correct a BGP routing misconfiguration that detoured European traffic to Australia. We have integrated our approach into several open source tools: Entrada, our open source data warehouse for DNS, a monitoring tool (ANTS), which has been operational for the last 2 years on a country-level top-level domain, and a DNS anonymization tool in use at a root server since March 2021.

The tools we developed in this paper are freely available, including patches to Knot, improvements to dnsanon, improvements to ENTRADA, and the new tool Anteater. Unfortunately data from the paper was from operational DNS systems and so cannot be shared due to privacy concerns.

This paper was made in part through DHS HSARPA Cyber Security Division via contract number HSHQDC-17-R-B0004-TTA.02-0006-I (PAADDOS) and by NWO, NSF CNS-1925737 (DIINER), and the Conconrdia Project, an European Union’s Horizon 2020 Research and Innovation program under Grant Agreement No 830927.

Categories
Internet Papers Publications Software releases

new paper “Chhoyhopper: A Moving Target Defense with IPv6” at NDSS MADWeb Workshop 2022

On April 24, 2022 we will publish a new paper titled “Chhoyhopper: A Moving Target Defense with IPv6” by A S M Rizvi and John Heidemann at the 4th Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb 2022), co-located with NDSS. We provide Chhoyhopper as an open-source tool for SSH and HTTPS—try it out!

From the abstract:

Services on the public Internet are frequently scanned, then subject to brute-force password attempts and Denial-of-Service (DoS) attacks. We would like to run such services stealthily, where they are available to friends but hidden from adversaries. In this work, we propose a discovery-resistant moving target defense named “Chhoyhopper” that utilizes the vast IPv6 address space to conceal publicly available services. The client meets the server at an IPv6 address that changes in a pattern based on a shared, pre-distributed secret and the time of day. By hopping over a /64 prefix, services cannot be found by active scanners, and passively observed information is useless after two minutes. We demonstrate our system with the two important applications—SSH and HTTPS, and make our system publicly available.

Client and server interaction in Chhoyhopper. A Client with the right secret key can only get access into the system.

Thanks: A S M Rizvi and John Heidemann’s work on this paper is supported, in part, by the DHS HSARPA Cyber Security Division via contract number HSHQDC-17-R-B0004-TTA.02-0006-I (PAADDoS), and by DARPA under Contract No. HR001120C0157 (SABRES). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF or DARPA. We thank Rayner Pais who prototyped an early version of Chhoyhopper and version in IPv4 hopping over ports.

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Anycast BGP Internet

new paper “Anycast Agility: Network Playbooks to Fight DDoS” at USENIX Security Symposium 2022

We will publish a new paper titled “Anycast Agility: Network Playbooks to Fight DDoS” by A S M Rizvi (USC/ISI), Leandro Bertholdo (University of Twente), João Ceron (SIDN Labs), and John Heidemann (USC/ISI) at the 31st USENIX Security Symposium in Aug. 2022.

A sample anycast playbook for a 3-site anycast deployment. Different routing configurations provide different traffic mixes. From [Rizvi22a, Table 5].

From the abstract:

IP anycast is used for services such as DNS and Content Delivery Networks (CDN) to provide the capacity to handle Distributed Denial-of-Service (DDoS) attacks. During a DDoS attack service operators redistribute traffic between anycast sites to take advantage of sites with unused or greater capacity. Depending on site traffic and attack size, operators may instead concentrate attackers in a few sites to preserve operation in others. Operators use these actions during attacks, but how to do so has not been described systematically or publicly. This paper describes several methods to use BGP to shift traffic when under DDoS, and shows that a response playbook can provide a menu of responses that are options during an attack. To choose an appropriate response from this playbook, we also describe a new method to estimate true attack size, even though the operator’s view during the attack is incomplete. Finally, operator choices are constrained by distributed routing policies, and not all are helpful. We explore how specific anycast deployment can constrain options in this playbook, and are the first to measure how generally applicable they are across multiple anycast networks.

Dataset used in this paper are listed at https://ant.isi.edu/datasets/anycast/anycast_against_ddos/index.html, and the software used in our work is at https://ant.isi.edu/software/anygility. They are provided as part of Call for Artifacts.

Acknowledgments: A S M Rizvi and John Heidemann’s work on this paper is supported, in part, by the DHS HSARPA Cyber Security Division via contract number HSHQDC-17-R-B0004-TTA.02-0006-I. Joao Ceron and Leandro Bertholdo’s work on this paper is supported by Netherlands Organisation for scientific research (4019020199), and European Union’s Horizon 2020 research and innovation program (830927). We would like to thank our anonymous reviewers for their valuable feedback. We are also grateful to the Peering and Tangled admins who allowed us to run measurements. We thank Dutch National Scrubbing Center for sharing DDoS data with us. We also thank Yuri Pradkin for his help to release our datasets.

Categories
DNS Papers Publications

New paper and talk “Institutional Privacy Risks in Sharing DNS Data” at Applied Networking Research Workshop 2021

Basileal Imana presented the paper “Institutional Privacy Risks in Sharing DNS Data” by Basileal Imana, Aleksandra Korolova and John Heidemann at Applied Networking Research Workshop held virtually from July 26-28th, 2021.

From the abstract:

We document institutional privacy as a new risk
posed by DNS data collected at authoritative servers, even
after caching and aggregation by DNS recursives. We are the
first to demonstrate this risk by looking at leaks of e-mail
exchanges which show communications patterns, and leaks
from accessing sensitive websites, both of which can harm an
institution’s public image. We define a methodology to identify queries from institutions and identify leaks. We show the
current practices of prefix-preserving anonymization of IP
addresses and aggregation above the recursive are not sufficient to protect institutional privacy, suggesting the need for
novel approaches.

Number of MX and DNSBL queries in a week-long root DNS data that can potentially leak email-related activity

The data from this paper is available upon request, please see our project page.

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Uncategorized

new conference paper “Anycast in Context: A Tale of Two Systems” at SIGCOMM 2021

We published a new paper “Anycast in Context: A Tale of Two Systems” by Thomas Koch, Ke Li, Calvin Ardi*, Ethan Katz-Bassett, Matt Calder**, and John Heidemann* (of Columbia, where not otherwise indicated, *USC/ISI, and **Microsoft and Columbia) at ACM SIGCOMM 2021.

From the abstract:

Anycast is used to serve content including web pages and DNS, and anycast deployments are growing. However, prior work examining root DNS suggests anycast deployments incur significant inflation, with users often routed to suboptimal sites. We reassess anycast performance, first extending prior analysis on inflation in the root DNS. We show that inflation is very common in root DNS, affecting more than 95% of users. However, we then show root DNS latency hardly matters to users because caching is so effective. These findings lead us to question: is inflation inherent to anycast, or can inflation be limited when it matters? To answer this question, we consider Microsoft’s anycast CDN serving latency-sensitive content. Here, latency matters orders of magnitude more than for root DNS. Perhaps because of this need, only 35% of CDN users experience any inflation, and the amount they experience is smaller than for root DNS. We show that CDN anycast latency has little inflation due to extensive peering and engineering. These results suggest prior claims of anycast inefficiency reflect experiments on a single application rather than anycast’s technical potential, and they demonstrate the importance of context when measuring system performance.

Tom also blogged about this work at APNIC.