DNS is one of the core building blocks of the Internet. In this paper, we investigate DNS resolution in a strict IPv6-only scenario and find that a substantial fraction of zones cannot be resolved. We point out, that the presence of an AAAA resource record for a zone’s nameserver does not necessarily imply that it is resolvable in an IPv6-only environment since the full DNS delegation chain must resolve via IPv6 as well. Hence, in an IPv6-only setting zones may experience an effect similar to what is commonly referred to as lame delegation. Our longitudinal study shows that the continuing centralization of the Internet has a large impact on IPv6 readiness, i.e., a small number of large DNS providers has, and still can, influence IPv6 readiness for a large number of zones. A single operator that enabled IPv6 DNS resolution–by adding IPv6 glue records–was responsible for around 20.3% of all zones in our dataset not resolving over IPv6 until January 2017. Even today, 10% of DNS operators are responsible for more than 97.5% of all zones that do not resolve using IPv6.@en

The Internet architecture has facilitated a multi-party, distributed, and heterogeneous physical infrastructure where routers from different vendors connect and inter-operate via IP. Such vendor heterogeneity can have important security and policy implications. For example, a security vulnerability may be specific to a particular vendor and implementation, and thus will have a disproportionate impact on particular networks and paths if exploited. From a policy perspective, governments are now explicitly banning particular vendors-or have threatened to do so.

Despite these critical issues, the composition of router vendors across the Internet remains largely opaque. Remotely identifying router vendors is challenging due to their strict security posture, indistinguishability due to code sharing across vendors, and noise due to vendor mergers. We make progress in overcoming these challenges by developing LFP, a tool that improves the coverage, accuracy, and efficiency of router fingerprinting as compared to the current state-of-the-art. We leverage LFP to characterize the degree of router vendor homogeneity within networks and the regional distribution of vendors. We then take a path-centric view and apply LFP to better understand the potential for correlated failures and fate-sharing. Finally, we perform a case study on inter and intra-United States data paths to explore the feasibility to make vendor-based routing policy decisions, i.e., whether it is possible to avoid a particular vendor given the current infrastructure.
@en

Honeypots have been used for decades to detect, monitor, and understand attempts of unauthorized use of information systems. Previous studies focused on characterizing the spread of malware, e.g., Mirai and other attacks, or proposed stealthy and interactive architectures to improve honeypot efficiency.

In this paper, we present insights and benefits gained from collaborating with an operational honeyfarm, i.e., a set of honeypots distributed around the globe with centralized data collection. We analyze data of about 400 million sessions over a 15-month period, gathered from a globally distributed honeyfarm consisting of 221 honeypots deployed in 55 countries. Our analysis unveils stark differences among the activity seen by the honeypots-some are contacted millions of times while others only observe a few thousand sessions. We also analyze the behavior of scouters and intruders of these honeypots. Again, some honeypots report orders of magnitude more interactions with command execution than others. Still, diversity is needed since even if we focus on the honeypots with the highest visibility, they see only a small fraction of the intrusions, including only 5% of the files. Thus, although around 2% of intrusions are visible by most of the honeypots in our honeyfarm, the rest are only visible to a few. We conclude with a discussion of the findings of work.@en

In this paper, we show that utilizing multiple protocols offers a unique opportunity to improve IP alias resolution and dual-stack inference substantially. Our key observation is that prevalent protocols, e.g., SSH and BGP, reply to unsolicited requests with a set of values that can be combined to form a unique device identifier. More importantly, this is possible by just completing the TCP hand-shake. Our empirical study shows that utilizing readily available scans and our active measurements can double the discovered IPv4 alias sets and more than 30× the dual-stack sets compared to the state-of-the-art techniques. We provide insights into our method's accuracy and performance compared to popular techniques.@en

Today, there is an increasing number of peering agreements between Hypergiants and networks that benefit millions of end-user. However, the majority of Autonomous Systems do not currently enjoy the benefit of interconnecting directly with Hypergiants to optimally select the path for delivering Hypergiant traffic to their users. In this paper, we develop and evaluate an architecture that can help this long tail of networks. With our proposed architecture, a network establishes an out-of-band communication channel with Hypergiants that can be two or more AS hops away and, optionally, with the transit provider. This channel enables the exchange of network information to better assign requests of end-users to appropriate Hypergiant servers. Our analysis using operational data shows that our architecture can optimize, on average, 15% of Hypergiants’ traffic and 11% of the overall traffic of networks that do not interconnect with Hypergiants. The gains are even higher during peak hours when available capacity can be scarce, up to 46% for some Hypergiants.

@en

IPv6 is being more and more adopted, in part to facilitate the millions of smart devices that have already been installed at home. Unfortunately, we find that the privacy of a substantial fraction of end-users is still at risk, despite the efforts by ISPs and electronic vendors to improve end-user security, e.g., by adopting prefix rotation and IPv6 privacy extensions. By analyzing passive data from a large ISP, we find that around 19% of end-users' privacy can be at risk. When we investigate the root causes, we notice that a single device at home that encodes its MAC address into the IPv6 address can be utilized as a tracking identifier for the entire end-user prefix-even if other devices use IPv6 privacy extensions. Our results show that IoT devices contribute the most to this privacy leakage and, to a lesser extent, personal computers and mobile devices. To our surprise, some of the most popular IoT manufacturers have not yet adopted privacy extensions that could otherwise mitigate this privacy risk. Finally, we show that third-party providers, e.g., hypergiants, can track up to 17% of subscriber lines in our study.

@en

Internet of Things (IoT) devices are becoming increasingly ubiquitous, e.g., at home, in enterprise environments, and in production lines. To support the advanced functionalities of IoT devices, IoT vendors as well as service and cloud companies operate IoT backendsÐthe focus of this paper. We propose a methodology to identify and locate them by (a) compiling a list of domains used exclusively by major IoT backend providers and (b) then identifying their server IP addresses. We rely on multiple sources, including IoT backend provider documentation, passive DNS data, and active scanning. For analyzing IoT traffic patterns, we rely on passive network flows from a major European ISP. Our analysis focuses on the top IoT backends and unveils diverse operational strategiesÐfrom operating their own infrastructure to utilizing the public cloud. We find that the majority of the top IoT backend providers are located in multiple locations and countries. Still, a handful are located only in one country, which could raise regulatory scrutiny as the client IoT devices are located in other regions. Indeed, our analysis shows that up to 35% of IoT traffic is exchanged with IoT backend servers located in other continents. We also find that at least six of the top IoT backends rely on other IoT backend providers. We also evaluate if cascading effects among the IoT backend providers are possible in the event of an outage, a misconfiguration, or an attack.

@en

Multipath TCP (MPTCP) extends traditional TCP to enable simultaneous use of multiple connection endpoints at the source and destination. MPTCP has been under active development since its standardization in 2013, and more recently in February 2020, MPTCP was upstreamed to the Linux kernel. In this paper, we provide the first broad analysis of MPTCPv0 in the Internet. We probe the entire IPv4 address space and an IPv6 hitlist to detect MPTCP-enabled systems operational on port 80 and 443. Our scans reveal a steady increase in MPTCP-capable IPs, reaching 9k+ on IPv4 and a few dozen on IPv6. We also discover a significant share of seemingly MPTCP-capable hosts, an artifact of middleboxes mirroring TCP options. We conduct targeted HTTP(S) measurements towards select hosts and find that middleboxes can aggressively impact the perceived quality of applications utilizing MPTCP. Finally, we analyze two complementary traffic traces from CAIDA and MAWI to shed light on the real-world usage of MPTCP. We find that while MPTCP usage has increased by a factor of 20 over the past few years, its traffic share is still quite low.

@en

In this paper, we report on a measurement study by researchers from several institutions that collected and analyzed network data to assess the impact of the first wave of COVID-19 (February-June 2020) on the Internet traffic. The datasets from Internet Service Providers, Internet Exchange Points, and academic networks, primarily in Europe, provide a unique view on the changes of Internet traffic due to pandemic and the lockdown that forced hundreds of millions of citizens to stay and work from home. The analysis shows that the increase of Internet traffic was about 15-20 % within a couple of weeks, an increase that is typically spread over multiple months under typical operation. However, traffic during peak hours does not increase by more than 5 %. The increase was noticeably higher for specific applications, e.g., remote work applications, teleconferencing, video on demand; in some cases up to 200 %. However, overall, the Internet reacted well to these unprecedented times.

@en

In March 2020, the World Health Organization declared the Corona Virus 2019 (COVID-19) outbreak a global pandemic. As a result, billions of people were either encouraged or forced by their governments to stay home to reduce the spread of the virus. This caused many to turn to the Internet for work, education, social interaction, and entertainment. With the Internet demand rising at an unprecedented rate, the question of whether the Internet could sustain this additional load emerged. To answer this question, this paper will review the impact of the first year of the COVID-19 pandemic on Internet traffic in order to analyze its performance. In order to keep our study broad, we collect and analyze Internet traffic data from multiple locations at the core and edge of the Internet. From this, we characterize how traffic and application demands change, to describe the "new normal,"and explain how the Internet reacted during these unprecedented times.

@en

In this paper, we show that adoption of the SNMPv3 network management protocol standard offers a unique - -but likely unintended - -opportunity for remotely fingerprinting network infrastructure in the wild. Specifically, by sending unsolicited and unauthenticated SNMPv3 requests, we obtain detailed information about the configuration and status of network devices including vendor, uptime, and the number of restarts. More importantly, the reply contains a persistent and strong identifier that allows for lightweight Internet-scale alias resolution and dual-stack association. By launching active Internet-wide SNMPv3 scan campaigns, we show that our technique can fingerprint more than 4.6 million devices of which around 350k are network routers. Not only is our technique lightweight and accurate, it is complementary to existing alias resolution, dual-stack inference, and device fingerprinting approaches. Our analysis not only provides fresh insights into the router deployment strategies of network operators worldwide, but also highlights potential vulnerabilities of SNMPv3 as currently deployed.

@en

The Domain Name System (DNS) is thought of as having the simple-sounding task of resolving domains into IP addresses. With its stub resolvers, different layers of recursive resolvers, authoritative nameservers, a multitude of query types, and DNSSEC, the DNS ecosystem is actually quite complex. In this paper, we introduce DNS Observatory: a new stream analytics platform that provides a bird's-eye view on the DNS. As the data source, we leverage a large stream of passive DNS observations produced by hundreds of globally distributed probes, acquiring a peak of 200 k DNS queries per second between recursive resolvers and authoritative nameservers. For each observed DNS transaction, we extract traffic features, aggregate them, and track the top-k DNS objects, e.g., the top authoritative nameserver IP addresses or the top domains. We analyze 1.6 trillion DNS transactions over a four month period. This allows us to characterize DNS deployments and traffic patterns, evaluate its associated infrastructure and performance, as well as gain insight into the modern additions to the DNS and related Internet protocols. We find an alarming concentration of DNS traffic: roughly half of the observed traffic is handled by only 1 k authoritative nameservers and by 10 AS operators. By evaluating the median delay of DNS queries, we find that the top 10 k nameservers have indeed a shorter response time than less popular nameservers, which is correlated with less router hops. We also study how DNS TTL adjustments can impact query volumes, anticipate upcoming changes to DNS infrastructure, and how negative caching TTLs affect the Happy Eyeballs algorithm. We find some popular domains with a a share of up to 90 % of empty DNS responses due to short negative caching TTLs. We propose actionable measures to improve uncovered DNS shortcomings.

@en