text: Underground online forums are platforms that enable trades of illicit services and stolen goods. Carding forums, in particular, are known for being focused on trading financial information. However, little evidence exists about the sellers that are present on carding forums, the precise types of products they advertise, and the prices buyers pay. Existing literature mainly focuses on the organisation and structure of the forums. Furthermore, studies on carding forums are usually based on literature review, expert interviews, or data from forums that have already been shut down. This paper provides first-of-its-kind empirical evidence on active forums where stolen financial data is traded. We monitored 5 out of 25 discovered forums, collected posts from the forums over a three-month period, and analysed them quantitatively and qualitatively. We focused our analyses on products, prices, seller prolificacy, seller specialisation, and seller reputation.
  @cite_19: 
  @cite_15: Crimeware-as-a-service (CaaS) has become a prominent component of the underground economy. CaaS provides a new dimension to cyber crime by making it more organized, automated, and accessible to criminals with limited technical skills. This paper dissects CaaS and explains the essence of the underground economy that has grown around it. The paper also describes the various crimeware services that are provided in the underground market.
  @cite_26: As consumers are increasingly using the Internet to manage their finances, there has been a concomitant increase in the risk of theft and fraud by cybercriminals. Hackers who acquire sensitive consumer data utilise information on their own, or sell the information in online forums for a significant profit. Few have considered the organisational composition of the participants engaged in the sale of stolen data, including the presence of managerial oversight, division of labour, coordination of roles and purposive associations between buyers, sellers and forum operators. Thus, this qualitative study will apply Best and Luckenbill's framework of social organisation to a sample of threads from publicly accessible web forums where individuals buy and sell stolen financial information. The implications of this study for criminologists, law enforcement, the intelligence community and information security researchers will be discussed in depth.
  @cite_7: February 2011 saw the emergence of Silk Road, the first successful online anonymous marketplace, in which buyers and sellers could transact with anonymity properties far superior to those available in alternative online or offline means of commerce. Business on Silk Road, primarily involving narcotics trafficking, rapidly boomed, and competitors emerged. At the same time, law enforcement did not sit idle, and eventually managed to shut down Silk Road in October 2013 and arrest its operator. Far from causing the demise of this novel form of commerce, the Silk Road take-down spawned an entire, dynamic, online anonymous marketplace ecosystem, which has continued to evolve to this day. This paper presents a long-term measurement analysis of a large portion of this online anonymous marketplace ecosystem, including 16 different marketplaces, over more than two years (2013- 2015). By using long-term measurements, and combining our own data collection with publicly available previous efforts, we offer a detailed understanding of the growth of the online anonymous marketplace ecosystem. We are able to document the evolution of the types of goods being sold, and assess the effect (or lack thereof) of adversarial events, such as law enforcement operations or large-scale frauds, on the overall size of the economy. We also provide insights into how vendors are diversifying and replicating across marketplaces, and how vendor security practices (e.g., PGP adoption) are evolving. These different aspects help us understand how traditional, physical-world criminal activities are developing an online presence, in the same manner traditional commerce diversified online in the 1990s.
summary: By applying a framework of social organisation, Holt @cite_26 identified specialisation on underground forums too. While one third of sellers offered various products, two thirds focused on only one product category. As the Symantec report @cite_19 illustrates, there are perpetrators specialising in writing viruses, in distributing malware or in monetising credit cards, for example. In recent years, Symantec has observed an increasing professionalisation in all aspects in the underground economy. Their findings are supported by research literature. Sood and Enbody @cite_15 also identified specialisation as a trend in underground markets. They argue that these markets are increasingly accessible to people with various technical skills. Hence, there is a division of labour due to differing skills. While analysing seller characteristics on black marketplaces, Soska and Christin @cite_7 discovered numerous specialised sellers, though there was a notable number of vendors selling different products as well.