It is easy to set up a cryptocurrency exchange, and there are hundreds of them around the world. The largest exchanges are hosted in a handful of countries, including the U.S., China, Singapore and several European nations, some of which have strong oversight regimes. But regulatory maturity and strictness vary widely, and there are many small, obscure exchanges where ransomware operators can convert their cryptocurrency into dollars, euros or rubles.

International experts have identified a group of countries that are struggling to combat cryptocurrency abuse and other forms of money laundering, including Ghana, Myanmar, Pakistan and Syria.

“You get into countries in Southeast Asia or in Africa or Eastern Europe, and they might not have adopted anything or have the resources for enforcement at all,” said Casey Jennings, another member of Seward & Kissel’s cryptocurrency practice. “It really does come down to whack-a-mole.”