For the mitigation of compromised Internet of Things (IoT) devices we rely on Internet Service Providers (ISPs) and their users. Given that devices are in the hands of their subscribers, what can ISPs realistically do? This study examines the effects of ISP countermeasures on infections caused by variants of the notorious Mirai family of IoT malware, still among the dominant families. We collect and analyze more than 4 years of longitudinal darknet data tracking Mirai-like infections in conjunction with threat intelligence data on various other IoT and non-IoT botnets across the globe from January 2016 to May 2020. We measure the effect of two ISP countermeasures on Mirai variant infection numbers: (i) reducing the attack surface (i.e., closing ports that are used by the malware for propagation) and (ii) ISPs increasing their general network hygiene and malware removal efforts (as observed by proxy of the remediation of infections of other families of IoT and non-IoT malware and reductions in the number of DDoS amplifiers in their networks). We map our infection data to 342 broadband providers that have the bulk of the broadband market share in their respective 83 countries. We find that the number of infections correlates strongly with the number of ISP subscribers (R2=0.55$). Yet, infection numbers can still vary by three orders of magnitude even for ISPs with comparable subscriber numbers. We observe that many ISPs, together with their subscribers, have reduced their attack surface for IoT compromise by blocking traffic to commonly-exploited infection vectors such as Telnet and FTP. We statistically estimate the impact of these reductions on infection levels and, counter-intuitively, find no significant impact. In contrast, we do find a significant impact for improving general network hygiene and best malware mitigation practices. ISPs that were more successful in reducing DDoS amplifiers and non-Mirai malware infections in their networks also end up with significantly lower Mirai infection rates. In other words, rather than investing in IoT-specific countermeasures like reducing the attack surface, our findings suggest that ISPs might be better off investing in general security efforts to improve network hygiene and clean up abuse. @en

Internet Service Providers (ISPs) are getting involved in remediating Internet of Things (IoT) infections of end users. This endeavor runs into serious usability problems. Given that it is usually unknown what kind of device is infected, they can only provide users with very generic cleanup advice, trying to cover all device types and remediation paths. Does this advice work? To what extent do users comply with the instructions? And does more compliance lead to higher cleanup rates? This study is the first to shed light on these questions. In partnership with an ISP, we designed a randomized control experiment followed up by a user survey. We randomly assigned 177 consumers affected by malware from the Mirai family to three different groups: (i) notified via a walled garden (quarantine network), (ii) notified via email, and (iii) no immediate notification, i.e. a control group. The notification asks the user to take five steps to remediate the infection. We conducted a phone survey with 95 of these customers based on communication-human information processing theory. We model the impact of the treatment, comprehension, and motivation on the compliance rate of each customer, while controlling for differences in demographics and infected device types. We also estimate the extent to which compliance leads to successful cleanup of the infected IoT devices. While only 24% of notified users perform all five remediation steps, 92% of notified users perform at least one action. Compliance increases the probability of successful cleanup by 32%, while the presence of competing malware reduces it by 54%. We provide an empirical basis to shape ISP best practices in the fight against IoT malware. @en

Many cybercriminal entrepreneurs lack the skills and techniques to provision certain parts of their business model, leading them to outsource these parts to specialized criminal vendors. Online anonymous markets, from Silk Road to AlphaBay, have been used to search for these products and contract with their criminal vendors. While one listing of a product generates high sales numbers, another identical listing fails to sell. In this paper, we investigate which factors determine the performance of cybercrime products.
To answer this question, we analyze scraped data on the business-to-business cybercrime segments of AlphaBay (2015-2017), consist- ing of 7,543 listings from 1,339 vendors, sold at least 126,934 times. We construct new variables to capture product differentiators and price. We capture the influence of vendor characteristics by identifying five distinct vendor profiles based on latent profile analysis of six properties. We leverage these product and vendor characteristics to empirically predict the performance of cybercrime products, whilst controlling for the lifespan and type of solution. Consistent with earlier insights into carding forums, we identify prevalent product differentiators to be influencing the relative success of a product. While all these product differentiators do correlate significantly with product performance, their explanatory power is lower than that of vendor profiles. When outsourcing, the vendor seems to be of more importance to the buyers than product differentiators.@en

Hosting providers are theoretically in a key position to combat cybercrime as they are often the entities renting out the resources that end up being abused by miscreants. Yet, notwithstanding hosting providers' current security measures to combat abuse, their responses vary widely. In many cases the response is ineffective, as empirical evidence suggests. To incentivize hosting providers to more effectively combat cybercrime and abuse however, we first require tools by which we can tell more or less secure hosting providers apart. These, may then be used to guide technical and policy questions surrounding the security of online hosting, and to provide empirical grounding to discussions about which potential solutions may move the hosting market towards more desirable security outcomes. Therefore, this book explores ways by which the security of hosting providers, may be measured through empirical data on cybercrime and the creation of metrics. The book explores questions of how such metrics may be constructed, to what extent they may be useful, and what the wider consequences of provider security negligence may be.@en

This paper presents the first empirical study based on ground-truth data of a major Bullet-Proof Hosting (BPH) provider, a company called Maxided. BPH allows miscreants to host criminal activities in support of various cybercrime business models such as phishing, botnets, DDoS, spam, and counterfeit pharmaceutical websites. Maxided was legally taken down by law enforcement and its backend servers were seized. We analyze data extracted from its backend databases and connect it to various external data sources to characterize Maxided's business model, supply chain, customers and finances. We reason about what the ``inside'' view reveals about potential chokepoints for disrupting BPH providers. We demonstrate the BPH landscape to have further shifted from agile resellers towards marketplace platforms with an oversupply of resources originating from hundreds of legitimate upstream hosting providers. We find the BPH provider to have few choke points in the supply chain amendable to intervention, though profit margins are very slim, so even a marginal increase in operating costs might already have repercussions that render the business unsustainable. The other intervention option would be to take down the platform itself.@en

To enhance competition and choice in the domain name system, ICANN introduced the new gTLD program, which added hundreds of new gTLDs (e.g. .nyc, .io) to the root DNS zone. While the program arguably increased the range of domain names available to consumers, it might also have created new opportunities for cybercriminals. To investigate that, we present the first comparative study of abuse in the domains registered under the new gTLD program and legacy gTLDs (18 in total, such as .com, .org). We combine historical datasets from various sources, including DNS zone files, WHOIS records, passive and active DNS and HTTP measurements, and 11 reputable abuse feeds to study abuse across gTLDs. We find that the new gTLDs appear to have diverted abuse from the legacy gTLDs: while the total number of domains abused for spam remains stable across gTLDs, we observe a growing number of spam domains in new gTLDs which suggests a shift from legacy gTLDs to new gTLDs. Although legacy gTLDs had a rate of 56.9 spam domains per 10,000 registrations (Q4 2016), new gTLDs experienced a rate of 526.6 in the same period-which is almost one order of magnitude higher. In this study, we also analyze the relationship between DNS abuse, operator security indicators and the structural properties of new gTLDs. The results indicate that there is an inverse correlation between abuse and stricter registration policies. Our findings suggest that cybercriminals increasingly prefer to register, rather than hack, domain names and some new gTLDs have become a magnet for malicious actors. ICANN is currently using these results to review the existing anti-abuse safeguards, evaluate their joint effects and to introduce more effective safeguards before an upcoming new gTLD rollout.

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Hosting providers play a key role in fighting web compromise, but their ability to prevent abuse is constrained by the security practices of their own customers. Shared hosting, offers a unique perspective since customers operate under restricted privileges and providers retain more control over configurations. We present the first empirical analysis of the distribution of web security features and software patching practices in shared hosting providers, the influence of providers on these security practices, and their impact on web compromise rates. We construct provider-level features on the global market for shared hosting -- containing 1,259 providers -- by gathering indicators from 442,684 domains. Exploratory factor analysis of 15 indicators identifies four main latent factors that capture security efforts: content security, webmaster security, web infrastructure security and web application security. We confirm, via a fixed-effect regression model, that providers exert significant influence over the latter two factors, which are both related to the software stack in their hosting environment. Finally, by means of GLM regression analysis of these factors on phishing and malware abuse, we show that the four security and software patching factors explain between 10% and 19% of the variance in abuse at providers, after controlling for size. For web-application security for instance, we found that when a provider moves from the bottom 10% to the best-performing 10%, it would experience 4 times fewer phishing incidents. We show that providers have influence over patch levels--even higher in the stack, where CMSes can run as client-side software--and that this influence is tied to a substantial reduction in abuse levels.@en

Over the years cybercriminals have misused the Domain Name System (DNS) - a critical component of the Internet - to gain profit. Despite this persisting trend, little empirical information about the security of Top-Level Domains (TLDs) and of the overall 'health' of the DNS ecosystem exists. In this paper, we present security metrics for this ecosystem and measure the operational values of such metrics using three representative phishing and malware datasets. We benchmark entire TLDs against the rest of the market. We explicitly distinguish these metrics from the idea of measuring security performance, because the measured values are driven by multiple factors, not just by the performance of the particular market player. We consider two types of security metrics: occurrence of abuse and persistence of abuse. In conjunction, they provide a good understanding of the overall health of a TLD. We demonstrate that attackers abuse a variety of free services with good reputation, affecting not only the reputation of those services, but of entire TLDs. We find that, when normalized by size, old TLDs like.com host more bad content than new generic TLDs. We propose a statistical regression model to analyze how the different properties of TLD intermediaries relate to abuse counts. We find that next to TLD size, abuse is positively associated with domain pricing (i.e. registries who provide free domain registrations witness more abuse). Last but not least, we observe a negative relation between the DNSSEC deployment rate and the count of phishing domains.

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A variety of botnets are used in attacks on financial services. Banks and security firms invest a lot of effort in detecting and combating malware-assisted takeover of customer accounts. A critical resource of these botnets is their command-and-control (C&C) infrastructure. Attackers rent or compromise servers to operate their C&C infrastructure. Hosting providers routinely take down C&C servers, but the effectiveness of this mitigation strategy depends on understanding how attackers select the hosting providers to host their servers. Do they prefer, for example, providers who are slow or unwilling in taking down C&Cs? In this paper, we analyze 7 years of data on the C&C servers of botnets that have engaged in attacks on financial services. Our aim is to understand whether attackers prefer certain types of providers or whether their C&Cs are randomly distributed across the whole attack surface of the hosting industry. We extract a set of structural properties of providers to capture the attack surface. We model the distribution of C&Cs across providers and show that the mere size of the provider can explain around 71% of the variance in the number of C&Cs per provider, whereas the rule of law in the country only explains around 1%. We further observe that price, time in business, popularity and ratio of vulnerable websites of providers relate signi ficantly with C&C counts. Finally, we find that the speed with which providers take down C&C domains has only a weak relation with C&C occurrence rates, adding only 1% explained variance. This suggests attackers have little to no preference for providers who allow long-lived C&C domains.

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Hosting services are associated with various security threats, yet the market has barely been studied empirically. Most security research has relied on routing data and equates providers with Autonomous Systems, ignoring the complexity and heterogeneity of the market. To overcome these limitations, we combined passive DNS data with WHOIS data to identify providers and some of their properties. We found 45,434 hosting providers, spread around a median address space size of 1,517 IP addresses. There is surprisingly little consolidation in the market, even though its services seem amenable to economies of scale. We applied cluster analysis on several measurable characteristics of providers. This uncovered a diverse set of business profiles and an indication of what fraction of the market fits each profile. The profiles are associated with significant differences in security performance, as measured by the uptime of phishing sites. This suggests the approach provides an effective way for security researchers to take the heterogeneity of the market into account.

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A lot of research has been devoted to understanding the technical properties of amplification DDoS attacks and the emergence of the DDoS-as-a-service economy, especially the so-called booters. Much less is known about the consequences for victimization patterns. We profile victims via data from amplification DDoS honeypots. We develop victimization rates and present explanatory models capturing key determinants of these rates. Our analysis demonstrates that the bulk of the attacks are directed at users in access networks, not at hosting, and even less at enterprise networks. We find that victimization in broadband ISPs is highly proportional to the number of ISP subscribers and that certain countries have significantly higher or lower victim rates which are only partially explained by institutional factors such as ICT development. We also find that victimization rate in hosting networks is proportional to the number of hosted domains and number of routed IP addresses and that content popularity has a minor impact on victimization rates. Finally, we reflect on the implications of these findings for the wider trend of commoditization in cybercrime.@en