A number of recent studies have investigated online anony- mous (“dark web”) marketplaces. Almost all leverage a “measurement-by-proxy” design, in which researchers scrape market public pages, and take buyer reviews as a proxy for ac- tual transactions, to gain insights into market size and revenue. Yet, we do not know if and how this method biases results. We build a framework to reason about marketplace mea- surement accuracy, and use it to contrast estimates projected from scrapes of Hansa Market with data from a back-end database seized by the police. We further investigate, by sim- ulation, the impact of scraping frequency, consistency and rate-limits. We find that, even with a decent scraping regimen, one might miss approximately 46% of objects – with scraped listings differing significantly from not-scraped listings on price, views and product categories. This bias also impacts revenue calculations. We find Hansa’s total market revenue to be US $50M, which projections based on our scrapes un- derestimate by a factor of four. Simulations further show that studies based on one or two scrapes are likely to suffer from a very poor coverage (on average, 14% to 30%, respectively). A high scraping frequency is crucial to achieve reliable coverage, even without a consistent scraping routine. When high-frequency scraping is difficult, e.g., due to deployed anti- scraping countermeasures, innovative scraper design, such as scraping most popular listings first, helps improve cover- age. Finally, abundance estimators can provide insights on population coverage when population sizes are unknown.@en

Researchers have observed the increasing commoditization of cybercrime, that is, the offering of capabilities, services, and resources as commodities by specialized suppliers in the underground economy. Commoditization enables outsourcing, thus lowering entry barriers for aspiring criminals, and potentially driving further growth in cybercrime. While there is evidence in the literature of specific examples of cybercrime commoditization, the overall phenomenon is much less understood. Which parts of cybercrime value chains are successfully commoditized, and which are not? What kind of revenue do criminal business-to-business (B2B) services generate and how fast are they growing? We use longitudinal data from eight online anonymous marketplaces over six years, from the original Silk Road to AlphaBay, and track the evolution of commoditization on these markets. We develop a conceptual model of the value chain components for dominant criminal business models. We then identify the market supply for these components over time. We find evidence of commoditization in most components, but the outsourcing options are highly restricted and transaction volume is often modest. Cash-out services feature the most listings and generate the largest revenue. Consistent with behavior observed in the context of narcotic sales, we also find a significant amount of revenue in retail cybercrime, i.e., business-to-consumer (B2C) rather than business to-business. We conservatively estimate the overall revenue for cybercrime commodities on online anonymous markets to be at least US $15M between 2011-2017. While there is growth, commoditization is a spottier phenomenon than previously assumed. @en