Category: Publications

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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.

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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.

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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.

 

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Publications Technical Report

new technical report “Poster: Lightweight Content-based Phishing Detection”

We released a new technical report “Poster: Lightweight Content-based Phishing Detection”, ISI-TR-698, available at http://www.isi.edu/publications/trpublic/files/tr-698.pdf.

The poster abstract and poster (included as part of the technical report) appeared at the poster session at the 36th IEEE Symposium on Security and Privacy in May 2015 in San Jose, CA, USA.

We have released an alpha version of our extension and source code here: http://www.isi.edu/ant/software/phish/.
We would greatly appreciate any help and feedback in testing our plugin!

From the abstract:

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Our browser extension hashes the content of a visited page and compares the hashes with a set of known good hashes. If the number of matches exceeds a threshold, the website is suspected as phish and an alert is displayed to the user.

Increasing use of Internet banking and shopping by a broad spectrum of users results in greater potential profits from phishing attacks via websites that masquerade as legitimate sites to trick users into sharing passwords or financial information. Most browsers today detect potential phishing with URL blacklists; while effective at stopping previously known threats, blacklists must react to new threats as they are discovered, leaving users vulnerable for a period of time. Alternatively, whitelists can be used to identify “known-good” websites so that off-list sites (to include possible phish) can never be accessed, but are too limited for many users. Our goal is proactive detection of phishing websites with neither the delay of blacklist identification nor the strict constraints of whitelists. Our approach is to list known phishing targets, index the content at their correct sites, and then look for this content to appear at incorrect sites. Our insight is that cryptographic hashing of page contents allows for efficient bulk identification of content reuse at phishing sites. Our contribution is a system to detect phish by comparing hashes of visited websites to the hashes of the original, known good, legitimate website. We implement our approach as a browser extension in Google Chrome and show that our algorithms detect a majority of phish, even with minimal countermeasures to page obfuscation. A small number of alpha users have been using the extension without issues for several weeks, and we will be releasing our extension and source code upon publication.

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Papers Publications

new conference paper “Connection-Oriented DNS to Improve Privacy and Security” in Oakland 2015

The paper “Connection-Oriented DNS to Improve Privacy and Security” will appear at the 36th IEEE Symposium on Security and Privacy in May 2015 in San Jose, CA, USA  (available at http://www.isi.edu/~liangzhu/papers/Zhu15b.pdf)

From the abstract:end_to_end_model_n_7

The Domain Name System (DNS) seems ideal for connectionless UDP, yet this choice results in challenges of eavesdropping that compromises privacy, source-address spoofing that simplifies denial-of-service (DoS) attacks on the server and third parties, injection attacks that exploit fragmentation, and reply-size limits that constrain key sizes and policy choices. We propose T-DNS to address these problems. It uses TCP to smoothly support large payloads and to mitigate spoofing and amplification for DoS. T-DNS uses transport-layer security (TLS) to provide privacy from users to their DNS resolvers and optionally to authoritative servers. TCP and TLS are hardly novel, and expectations about DNS suggest connections will balloon client latency and overwhelm server with state. Our contribution is to show that T-DNS significantly improves security and privacy: TCP prevents denial-of-service (DoS) amplification against others, reduces the effects of DoS on the server, and simplifies policy choices about key size. TLS protects against eavesdroppers to the recursive resolver. Our second contribution is to show that with careful implementation choices, these benefits come at only modest cost: end-to-end latency from TLS to the recursive resolver is only about 9% slower when UDP is used to the authoritative server, and 22% slower with TCP to the authoritative. With diverse traces we show that connection reuse can be frequent (60–95% for stub and recursive resolvers, although half that for authoritative servers), and after connection establishment, experiments show that TCP and TLS latency is equivalent to UDP. With conservative timeouts (20 s at authoritative servers and 60 s elsewhere) and estimated per-connection memory, we show that server memory requirements match current hardware: a large recursive resolver may have 24k active connections requiring about 3.6 GB additional RAM. Good performance requires key design and implementation decisions we identify: query pipelining, out-of-order responses, TCP fast-open and TLS connection resumption, and plausible timeouts.

The work in the paper is by Liang Zhu, Zi Hu and John Heidemann (USC/ISI), Duane Wessels and Allison Mankin (both of Verisign Labs), and Nikita Somaiya (USC/ISI).  Earlier versions of this paper were released as ISI-TR-688 and ISI-TR-693; this paper adds results and supercedes that work.

The data in this paper is available to researchers at no cost on request. Please see T-DNS-experiments-20140324 at dataset page.

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Papers Publications

new workshop paper “Privacy Principles for Sharing Cyber Security Data” in IWPE 15

The paper “Privacy Principles for Sharing Cyber Security Data” (available at https://www.isi.edu/~calvin/papers/Fisk15a.pdf) will appear at the International Workshop on Privacy Engineering (co-located with IEEE Symposium on Security and Privacy) on May 21, 2015 in San Jose, California.

From the abstract:

Sharing cyber security data across organizational boundaries brings both privacy risks in the exposure of personal information and data, and organizational risk in disclosing internal information. These risks occur as information leaks in network traffic or logs, and also in queries made across organizations. They are also complicated by the trade-offs in privacy preservation and utility present in anonymization to manage disclosure. In this paper, we define three principles that guide sharing security information across organizations: Least Disclosure, Qualitative Evaluation, and Forward Progress. We then discuss engineering approaches that apply these principles to a distributed security system. Application of these principles can reduce the risk of data exposure and help manage trust requirements for data sharing, helping to meet our goal of balancing privacy, organizational risk, and the ability to better respond to security with shared information.

The work in the paper is by Gina Fisk (LANL), Calvin Ardi (USC/ISI), Neale Pickett (LANL), John Heidemann (USC/ISI), Mike Fisk (LANL), and Christos Papadopoulos (Colorado State). This work is supported by DHS S&T, Cyber Security division.

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Papers Publications

new workshop paper “Assessing Affinity Between Users and CDN Sites” in TMA 2015

The paper “Assessing Affinity Between Users and CDN Sites” (available at http://www.isi.edu/~xunfan/research/Fan15a.pdf) will appear at the Traffic Monitoring and Analysis Workshop in April 2015 in Barcelona, Spain.

From the abstract:

count_cid_per_clientLarge web services employ CDNs to improve user performance. CDNs improve performance by serving users from nearby FrontEnd (FE) Clusters. They also spread users across FE Clusters when one is overloaded or unavailable and others have unused capacity. Our paper is the first to study the dynamics of the user-to-FE Cluster mapping for Google and Akamai from a large range of client prefixes. We measure how 32,000 prefixes associate with FE Clusters in their CDNs every 15 minutes for more than a month. We study geographic and latency effects of mapping changes, showing that 50–70% of prefixes switch between FE Clusters that are very distant from each other (more than 1,000 km), and that these shifts sometimes (28–40% of the time) result in large latency shifts (100 ms or more). Most prefixes see large latencies only briefly, but a few (2–5%) see high latency much of the time. We also find that many prefixes are directed to several countries over the course of a month, complicating questions of jurisdiction.

Citation: Xun Fan, Ethan Katz-Bassett and John Heidemann.Assessing Affinity Between Users and CDN Sites. To appear in Traffic Monitoring and Analysis Workshop. Barcelona, Spain. April, 2015.

All data in this paper is available to researchers at no cost on request. Please see our CDN affinity dataset webpage.

This research is partially sponsored by the Department of Homeland Security (DHS) Science and Technology Directorate, HSARPA, Cyber Security Division, BAA 11-01-RIKA and Air Force Re-search Laboratory, Information Directorate under agreement number FA8750-12-2-0344, NSF CNS-1351100, and via SPAWAR Systems Center Pacific under Contract No. N66001-13-C-3001. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwith-standing any copyright notation thereon. The views contained herein are those of the authors and
do not necessarily represent those of DHS or the U.S. Government.

 

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Papers Publications

new conference paper “BotTalker: Generating Encrypted, Customizable C&C Traces” in HST 2015

The paper “BotTalker: Generating Encrypted, Customizable C&C Traces” will appear at the 14th annual IEEE Symposium on Technologies for Homeland Security (HST ’15) in April 2015 (available at http://www.cs.colostate.edu/~zhang/papers/BotTalker.pdf)

From the abstract:

Encrypted botnets have seen an increasingalerts-types-breakdown-originaluse  in recent years. To enable research in detecting encrypted botnets researchers need samples of encrypted botnet traces with ground truth, which are very hard to get. Traces that are available are not customizable, which prevents testing under various controlled scenarios. To address this problem we introduce BotTalker, a tool that can be used to generate customized encrypted botnet communication traffic. BotTalker emulates the actions a bot would take to encrypt communication. It includes a highly configurable encrypted-traffic converter along with real, non- encrypted bot traces and background traffic. The converter is able to convert non-encrypted botnet traces into encrypted ones by providing customization along three dimensions: (a) selection of real encryption algorithm, (b) flow or packet level conversion, SSL emulation and (c) IP address substitution. To the best of our knowledge, BotTalk is the first work that provides users customized encrypted botnet traffic. In the paper we also apply BotTalker to evaluate the damage result from encrypted botnet traffic on a widely used botnet detection system – BotHunter and two IDS’ – Snort and Suricata. The results show that encrypted botnet traffic foils bot detection in these systems.

This work is advised by Christos Papadopoulos and supported by LACREND.

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Papers Publications

new workshop paper “Measuring DANE TLSA Deployment” in TMA 2015

The paper “Measuring DANE TLSA Deployment” will appear at the Traffic Monitoring and Analysis Workshop in April 2015 in Barcelona, Spain (available at http://www.isi.edu/~liangzhu/papers/dane_tlsa.pdf).

From the abstract:

The DANE (DNS-based Authentication of Named Entities) framework uses DNSSEC to provide a source of trust, and with TLSA it can serve as a root of trust for TLS certificates. This serves to complement traditional certificate authentication methods, which is important given the risks inherent in trusting hundreds of organizations—risks already demonstrated with multiple compromises. The TLSA protocol was published in 2012, and this paper presents the first systematic study of its deployment. We studied TLSA usage, developing a tool that actively probes all signed zones in .com and .net for TLSA records. We find the TLSA use is early: in our latest measurement, of the 485k signed zones, we find only 997 TLSA names. We characterize how it is being used so far, and find that around 7–13% of TLSA records are invalid. We find 33% of TLSA responses are larger than 1500 Bytes and will very likely be fragmented.

The work in the paper is by Liang Zhu (USC/ISI), Duane Wessels and Allison Mankin (both of Verisign Labs), and John Heidemann (USC/ISI).

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Papers Publications

new conference paper “When the Internet Sleeps: Correlating Diurnal Networks With External Factors” in IMC 2014

The paper “When the Internet Sleeps: Correlating Diurnal Networks With External Factors” will appear at ACM Internet Measurements Conference 2014 in Vancouver, Canada (available at http://www.isi.edu/~johnh/PAPERS/Quan14c/ with cite and pdf, or direct pdf).

Predicting longitude from observed diurnal phase ([Quan14c], figure 14c)
Predicting longitude from observed diurnal phase for 287k geolocatable, diurnal blocks ([Quan14c], figure 14c)
From the abstract:

As the Internet matures, policy questions loom larger in its operation. When should an ISP, city, or government invest in infrastructure? How do their policies affect use? In this work, we develop a new approach to evaluate how policies, economic conditions and technology correlates with Internet use around the world. First, we develop an adaptive and accurate approach to estimate block availability, the fraction of active IP addresses in each /24 block over short timescales (every 11 minutes). Our estimator provides a new lens to interpret data taken from existing long-term outage measurements, thus requiring no additional traffic. (If new collection was required, it would be lightweight, since on average, outage detection requires less than 20 probes per hour per /24 block; less than 1% of background radiation.) Second, we show that spectral analysis of this measure can identify diurnal usage: blocks where addresses are regularly used during part of the day and idle in other times. Finally, we analyze data for the entire responsive Internet (3.7M /24 blocks) over 35 days. These global observations show when and where the Internet sleeps—networks are mostly always-on in the US and Western Europe, and diurnal in much of Asia, South America, and Eastern Europe. ANOVA (Analysis of Variance) testing shows that diurnal networks correlate negatively with country GDP and electrical consumption, quantifying that national policies and economics relate to networks.

Citation: Lin Quan, John Heidemann, and Yuri Pradkin. When the Internet Sleeps: Correlating Diurnal Networks With External Factors. In Proceedings of the ACM Internet Measurement Conference, p. to appear. Vancouver, BC, Canada, ACM. November, 2014.

All data in this paper is available to researchers at no cost, and source code to our analysis tools is available on request; see our diurnal datasets webpage.

This work is partly supported by DHS S&T, Cyber Security division, agreement FA8750-12-2-0344 (under AFRL) and N66001-13-C-3001 (under SPAWAR).  The views contained
herein are those of the authors and do not necessarily represent those of DHS or the U.S. Government.  This work was classified by USC’s IRB as non-human subjects research (IIR00001648).