Categories
Papers Publications

new conference paper “Measuring the Latency and Pervasiveness of TLS Certificate Revocation” in PAM 2016

The paper “Measuring the Latency and Pervasiveness of TLS Certificate Revocation” will appear at Passive and Active Measurements Conference in March 2016 in Heraklion, Crete, Greece  (available at http://www.isi.edu/~liangzhu/papers/Zhu16a.pdf)

From the abstract:

Today, Transport-Layer Security (TLS) is the bedrock of Internet security for the web and web-derived applications. TLS depends on the X.509 Public Key Infrastructure (PKI) to authenticate endpoint
identity. An essential part of a PKI is the ability to quickly revoke certificates, for example, after a key compromise. Today the Online Certificate Status Protocol (OCSP) is the most common way to quickly distribute revocation information. However, prior and current concerns about OCSP latency and privacy raise questions about its use. We examine OCSP using passive network monitoring of live traffic at the Internet uplink of a large research university and verify the results using active scans. Our measurements show that the median latency of OCSP queries is quite good: only 20 ms today, much less than the 291 ms observed in 2012. This improvement is because content delivery networks (CDNs) serve most OCSP traffic today; our measurements show 94% of queries are served by CDNs. We also show that OCSP use is ubiquitous today: it is used by all popular web browsers, as well as important non-web applications such as MS-Windows code signing.

The work in the paper is by Liang Zhu (USC/ISI), Johanna Amann (ICSI) and John Heidemann (USC/ISI). The active probe dataset in this paper is available upon request.

Categories
Publications Technical Report

new technical report “Assessing Co-Locality of IP Blocks”

We have released a new technical report “Assessing Co-Locality of IP Blocks”, CSU TR15-103, available at http://www.cs.colostate.edu/TechReports/Reports/2015/tr15-103.pdf.

From the abstract:

isi_all_blocks_clustersCount_CDF
CDF of number of clusters per block, suggesting the number of potential multi-location blocks. (Figure 2 from [Gharaibeh15a].)

Many IP Geolocation services and applications assume that all IP addresses with the same /24 IPv4 prefix (a /24 block) are in the same location. For blocks that contain addresses in very different locations (such blocks identifying network backbones), this assumption can result in large geolocation error. This paper evaluates this assumption using a large dataset of 1.41M /24 blocks extracted from a delay measurements dataset for the entire
responsive IPv4 address space. We use hierarchal clustering to find clusters of IP addresses with similar observed delay measurements within /24 blocks. Blocks with multiple clusters often span different geographic locations. We evaluate this claim against two ground-truth datasets, confirming that 93% of identified multi-cluster blocks are true positives with multiple locations, while only 13% of blocks identified as single-cluster appear to be multi-location in ground truth. Applying the clustering process to the whole dataset suggests that about 17% (247K) of blocks are likely multi-location.

This work is by Manaf Gharaibeh, Han Zhang, Christos Papadopoulos (Colorado State University), and John Heidemann (USC/ISI). The datasets used in this work are new analysis of an existing geolocation dataset as collected by Hu et al. (http://www.isi.edu/~johnh/PAPERS/Hu12a.pdf).  These source datasets are available upon request from http://www.predict.org and via our website, and we expect trial datasets in our new work to also be available there and through PREDICT by the end of 2015.

Categories
Software releases

timefind v1.0.2.2 released

timefind v1.0.2.2 has been released (available at https://ant.isi.edu/software/timefind/).

Scientists at Los Alamos National Laboratory and at USC/ISI have developed two tools to handle indexing and selection of multiple network data types: indexer and timefind.

Most of us have processed large amounts of timestamped data. Given .pcap spanning 2010-2015, we might want to downselect on a time range, e.g., 2015-Jan-01 to 2015-Feb-01. An existing way to downselect would be to build fragile regexes and walk the directory tree for each search: inefficient and inevitably re-written.

indexer will walk through all your data and index the timestamps of the earliest and latest records.

timefind will then use the indexes and retrieve the filenames that overlap with the given time range input. To downselect 2015-Jan-01 to 2015-Feb-01 on “dns” data, use:

timefind --begin="2015-01-01" --end="2015-02-01" dns

It’s that simple and consistent.

Categories
Software releases

Digit tool for T-DNS privacy updated to match current internet-draft

Digit is our DNS client side tool that can perform DNS queries via different protocols such as UDP, TCP, TLS. This tool is primarily designed to evaluate the client side latency of using DNS over TCP/TLS.

IANA has allocated port 853 to use TLS/DTLS for DNS temporarily in the most recent version of Internet draft “DNS over TLS: Initiation and Performance Considerations” (draft-ietf-dprive-dns-over-tls-01).

To track the current specification, we have updated Digit to do direct TLS on port 853 by default, with TCP. STARTTLS and other protocols as options for comparison.

These changes are available as Digit-1.4.1 at https://ant.isi.edu/software/tdns/index.html.

Categories
Announcements Students

student recruiting for Fall 2016

ANT will be looking for one (or perhaps two) strong PhD students interested in our areas of research to start at USC in Fall 2016. If you’re interested in working with our research group, please apply to our PhD program (the deadline is December 15, 2015 and the CS department has application information).

For MS students at USC, we sometimes to directed research projects, usually as part of CSci551 or CSci651–if you’re interested, please read our webpage with specific MS-student advice.

For undergraduates interested in research, please see our webpage with specific undgraduate-student advice.

Categories
Papers Publications

new conference paper “Detecting Malicious Activity with DNS Backscatter”

The paper “Detecting Malicious Activity with DNS Backscatter” will appear at the ACM Internet Measurements Conference in October 2015 in Tokyo, Japan.  A copy is available at http://www.isi.edu/~johnh/PAPERS/Fukuda15a.pdf).

How newtork activity generates DNS backscatter that is visible at authority servers. (Figure 1 from [Fukuda15a]).
How newtork activity generates DNS backscatter that is visible at authority servers. (Figure 1 from [Fukuda15a]).
From the abstract:

Network-wide activity is when one computer (the originator) touches many others (the targets). Motives for activity may be benign (mailing lists, CDNs, and research scanning), malicious (spammers and scanners for security vulnerabilities), or perhaps indeterminate (ad trackers). Knowledge of malicious activity may help anticipate attacks, and understanding benign activity may set a baseline or characterize growth. This paper identifies DNS backscatter as a new source of information about network-wide activity. Backscatter is the reverse DNS queries caused when targets or middleboxes automatically look up the domain name of the originator. Queries are visible to the authoritative DNS servers that handle reverse DNS. While the fraction of backscatter they see depends on the server’s location in the DNS hierarchy, we show that activity that touches many targets appear even in sampled observations. We use information about the queriers to classify originator activity using machine-learning. Our algorithm has reasonable precision (70-80%) as shown by data from three different organizations operating DNS servers at the root or country-level. Using this technique we examine nine months of activity from one authority to identify trends in scanning, identifying bursts corresponding to Heartbleed and broad and continuous scanning of ssh.

The work in this paper is by Kensuke Fukuda (NII/Sokendai) and John Heidemann (USC/ISI) and was begun when Fukuda-san was a visiting scholar at USC/ISI.  Kensuke Fukuda’s work in this paper is partially funded by Young Researcher Overseas Visit Program by Sokendai, JSPS Kakenhi, and the Strategic International Collaborative R&D Promotion Project of the Ministry of Internal Affairs and Communication in Japan, and by the European Union Seventh Framework Programme.  John Heidemann’s work is partially supported by US DHS S&T, Cyber Security division.

Some of the datasets in this paper are available to researchers, either from the authors or through DNS-OARC.  We list DNS backscatter datasets and methods to obtain them at https://ant.isi.edu/datasets/dns_backscatter/index.html.

 

Categories
Collaborations Social

thanks to visiting scholar Kensuke Fukuda

We would like to thank Kensuke Fukuda for joining us as a visiting scholar from September 2014 to January 2015.  It was great having Fukuda-san join us from the National Institute of Informatics in Japan and share is interest in network measurement and DNS.

Watch here for details about the technical results of his visit.  For now though, a photo of our going-away lunch with Kenuske, his family, and most of rest of the ANT lab taken in January 2015.

The going away lunch for Kensuke Fukuda (fifth from the right), celebrating his visiting as a scholar, with the ANT lab.
The going away lunch for Kensuke Fukuda (fifth from the right), celebrating his visiting as a scholar, with the ANT lab.
Categories
Students

congratulations to Romello Goodman for his summer undergrad internship

I would to thank Romello Goodman for his summer internship at ANT, as part of the USC SURE (Viterbi Summer Undergraduate Research Experience) program.   Romello interned with us as part of his studies at Cal Lutheran (Thousand Oaks, California) where he is an undergraduate student in computer science.

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Romello Goodman with his poster about his reverse-DNS crawling work, at the SURE poster session.

Romello’s project was developing a reverse DNS crawler for IPv4 to provide bulk domain name data that feeds into other research projects such as our Internet census work.  He explored several approaches and his code is running today crawling the whole Internet.  We have used other sources of DNS data in the past–we look forward to his approaches providing a regularly updated dataset for evaluation.

We expect to make datasets from his research available in the future as they are completed.  His software is currently available.

His research at ISI was jointly advised by Yuri Pradkin and John Heidemann.

Categories
Announcements

website refresh

The new ANT web home page
The new ANT web home page

After more than ten years of hand-coded, mostly-themed HTML, we’ve finally revamped our website with Jekyll and moved it to our own server at https://ant.isi.edu/.  We love producing papers, software, and datasets, and we now finally automate the tedious task cross-referencing these across our pages.  It also brings more consistent theming, and our server brings HTTPS for better privacy.

Thanks to Calvin Ardi for kicking this off, and to almost everyone in the group for pitching in to go over old pages.

Categories
Students

congratulations to Xun Fan for his new PhD

I would like to congratulate Dr. Xun Fan for defending his PhD in May 2015 and completing his doctoral dissertation “Enabling Efficient Service Enumeration Through Smart Selection of Measurements” in July 2015.

Xun Fan (left) and John Heidemann, after Xun's PhD defense.
Xun Fan (left) and John Heidemann, after Xun’s PhD defense.

From the abstract:

The Internet is becoming more and more important in our daily lives. Both the government and industry invest in the growth of the Internet, bringing more users to the world of networks. As the Internet grows, researchers and operators need to track and understand the behavior of global Internet services to achieve smooth operation. Active measurements are often used to study behavior of large Internet service, and efficient service enumeration is required. For example, studies of Internet topology may need active probing to all visible network prefixes; monitoring large replicated service requires periodical enumeration of all service replicas. To achieve efficient service enumeration, it is important to select probing sources and destinations wisely. However, there are challenges for making smart selection of probing sources and destinations. Prior methods to select probing destinations are either inefficient or hard to maintain. Enumerating replicas of large Internet services often requires many widely distributed probing sources. Current measurement platforms don’t have enough probing sources to approach complete enumeration of large services.

This dissertation makes the thesis statement that smart selection of probing sources and destinations enables efficient enumeration of global Internet services to track and understand their behavior. We present three studies to demonstrate this thesis statement. First, we propose new automated approach to generate a list of destination IP addresses that enables efficient enumeration of Internet edge links. Second, we show that using large number of widely distributed open resolvers enables efficient enumeration of anycast nodes which helps study abnormal behavior of anycast DNS services. In our last study, we efficiently enumerate Front-End (FE) Clusters of Content Delivery Networks (CDNs) and use the efficient enumeration to track and understand the dynamics of user-to-FE Cluster mapping of large CDNs. We achieve the efficient enumeration of CDN FE Clusters by selecting probing sources from a large set of open resolvers. Our selected probing sources have smaller number of open resolvers but provide same coverage on CDN FE Cluster as the larger set.

In addition to our direct results, our work has also been used by several published studies to track and understand the behavior of Internet and large network services. These studies not only support our thesis as additional examples but also suggest this thesis can further benefit many other studies that need efficient service enumeration to track and understand behavior of global Internet services.