When hackers stole $81 million from a bank in Bangladesh last year, fingers were eventually pointed at North Korea. The accusation indicated that North Korea’s hackers appeared willing to go after targets — a bank in a developing economy hardly considered a big player in international politics — not normally associated with nation-state cyberattacks.

The breach was also evidence that if you want to try out a new attack, you don’t start on Wall Street or Western Europe. Instead, you choose something in an economy without the robust defenses of, say, Citibank. As Sheera Frenkel reports, what intrigued security researchers about the attack was that its target was the Bank of Bangladesh’s access to an electronic banking system called Swift. It is used throughout the world to transfer billions of dollars among banks. Learning how to get access to a bank’s Swift account could lead to a heist of billions from the global banking system.