How to Learn Klingon Without a Dictionary: Detection and Measurement of Black Keywords Used by the Underground Economy

Thursday Aug 3rd, 12-1PM @ BA5205

Speaker: Prof Haixin Duan from Tsinghua

How to Learn Klingon Without a Dictionary: Detection and Measurement of Black Keywords Used by the Underground Economy

Online underground economy is an important channel that connects the merchants of illegal products and their buyers, which is also constantly monitored by legal authorities. As one common way for evasion, the merchants and buyers together create a vocabulary of jargons (called “black keywords” in this paper) to disguise the transaction (e.g., “smack” is one street name for “heroin” [1]).  Understanding black keywords is of great importance to track and disrupt the underground economy, but it is also prohibitively difficult: the investigators have to infiltrate the inner circle of criminals to learn their meanings, a task both risky and time- consuming. In this talk Prof. Duan  will introduce their attempt towards capturing and understanding the ever-changing black keywords. We investigated the underground business promoted through blackhat SEO (search engine optimization) and demonstrate that the black keywords targeted by the SEOers can be discovered through a fully automated approach. Together with Baidu, the leading search engine in China,  Prof. Duan’s team built a system called KDES (Keywords Detection and Expansion System), and applied it to the search results of Baidu. So far, they have already identified 478,879 black keywords which were clustered under 1,522 core words based on text similarity. They further extracted the information like emails, mobile phone numbers and instant messenger IDs from the pages and domains relevant to the underground business. Such information is helpful to understand the underground economy of China in particular.

Dr. Haixin Duan is a professor in the Institute for Network Science and Cyberspace at Tsinghua University. He was once a visiting scholar at UC Berkeley and a senior scientist in International Computer Science Institute(ICSI).  Professor Duan focuses his research on network security, including security of network protocols, intrusion detection and underground economy detection. His research results were published in top security conferences like Security & Privacy, USENIX Security, CCS and NDSS. One of his research won Distinguished Paper Award of NDSS 2016. Prof. Duan won the  Excellence Talent Award for Cybersecurity (one of ten awardees from both academia and industry in China).