  As the largest blockchain platform that supports smart contracts, Ethereum
has developed with an incredible speed. Yet due to the anonymity of blockchain,
the popularity of Ethereum has fostered the emergence of various illegal
activities and money laundering by converting ill-gotten funds to cash. In the
traditional money laundering scenario, researchers have uncovered the prevalent
traits of money laundering. However, since money laundering on Ethereum is an
emerging means, little is known about money laundering on Ethereum. To fill the
gap, in this paper, we conduct an in-depth study on Ethereum money laundering
networks through the lens of a representative security event on \textit{Upbit
Exchange} to explore whether money laundering on Ethereum has traditional
traits. Specifically, we construct a money laundering network on Ethereum by
crawling the transaction records of \textit{Upbit Hack}. Then, we present five
questions based on the traditional traits of money laundering networks. By
leveraging network analysis, we characterize the money laundering network on
Ethereum and answer these questions. In the end, we summarize the findings of
money laundering networks on Ethereum, which lay the groundwork for money
laundering detection on Ethereum.
