In 2016 North Korean hackers planned a $1bn raid on Bangladesh’s national bank and came within an inch of success – it was only by a fluke that all but $81m of the transfers were halted, report Geoff White and Jean H Lee of BBC. But how did one of the world’s poorest and most isolated countries train a team of elite cyber-criminals?

It all started with a malfunctioning printer. It’s just part of modern life, and so when it happened to staff at Bangladesh Bank they thought the same thing most of us do: another day, another tech headache. It didn’t seem like a big deal.

But this wasn’t just any printer, and it wasn’t just any bank.

Bangladesh Bank is the country’s central bank, responsible for overseeing the precious currency reserves of a country where millions live in poverty.

And the printer played a pivotal role. It was located inside a highly secure room on the 10th floor of the bank’s main office in Dhaka, the capital. Its job was to print out records of the multi-million-dollar transfers flowing in and out of the bank.

When staff found it wasn’t working, at 08:45 on Friday 5 February 2016, “we assumed it was a common problem just like any other day,” duty manager Zubair Bin Huda later told police. “Such glitches had happened before.”

In fact, this was the first indication that Bangladesh Bank was in a lot of trouble. Hackers had broken into its computer networks, and at that very moment were carrying out the most audacious cyber-attack ever attempted. Their goal: to steal a billion dollars.

To spirit the money away, the gang behind the heist would use fake bank accounts, charities, casinos and a wide network of accomplices.

But who were these hackers and where were they from?

According to investigators the digital fingerprints point in just one direction: to the government of North Korea.

That North Korea would be the prime suspect in a case of cyber-crime might to some be a surprise. It’s one of the world’s poorest countries, and largely disconnected from the global community – technologically, economically, and in almost every other way.

In the cyber-security industry the North Korean hackers are known as the Lazarus Group, a reference to a biblical figure who came back from the dead; experts who tackled the group’s computer viruses found they were equally resilient.

Little is known about the group, though the FBI has painted a detailed portrait of one suspect: Park Jin-hyok, who also has gone by the names Pak Jin-hek and Park Kwang-jin.

It describes him as a computer programmer who graduated from one of the country’s top universities and went to work for a North Korean company, Chosun Expo, in the Chinese port city of Dalian, creating online gaming and gambling programs for clients around the world.

While in Dalian, he set up an email address, created a CV, and used social media to build a network of contacts.

The FBI says that while he worked as a programmer by day, he was a hacker by night.

In June 2018, US authorities charged Park with one count of conspiracy to commit computer fraud and abuse, and one count of conspiracy to commit wire fraud (fraud involving mail, or electronic communication) between September 2014 and August 2017. He faces up to 20 years in prison if he is ever tracked down. (He returned from China to North Korea four years before the charges were filed.)

But Park, if that is his real name, didn’t become a hacker for the state overnight. He is one of thousands of young North Koreans who have been cultivated from childhood to become cyber-warriors – talented mathematicians as young as 12 taken from their schools and sent to the capital, where they are given intensive tuition from morning til night.
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When the bank’s staff rebooted the printer, they got some very worrying news. Spilling out of it were urgent messages from the Federal Reserve Bank in New York – the “Fed” – where Bangladesh keeps a US-dollar account. The Fed had received instructions, apparently from Bangladesh Bank, to drain the entire account – close to a billion dollars.

The Bangladeshis tried to contact the Fed for clarification, but thanks to the hackers’ very careful timing, they couldn’t get through.

The hack started at around 20:00 Bangladesh time on Thursday 4 February. But in New York it was Thursday morning, giving the Fed plenty of time to (unwittingly) carry out the hackers’ wishes while Bangladesh was asleep.

The next day, Friday, was the start of the Bangladeshi weekend, which runs from Friday to Saturday. So the bank’s HQ in Dhaka was beginning two days off. And when the Bangladeshis began to uncover the theft on Saturday, it was already the weekend in New York.

“So you see the elegance of the attack,” says US-based cyber-security expert Rakesh Asthana. “The date of Thursday night has a very defined purpose. On Friday New York is working, and Bangladesh Bank is off. By the time Bangladesh Bank comes back on line, the Federal Reserve Bank is off. So it delayed the whole discovery by almost three days.”

And the hackers had another trick up their sleeve to buy even more time. Once they had transferred the money out of the Fed, they needed to send it somewhere. So they wired it to accounts they’d set up in Manila, the capital of the Philippines. And in 2016, Monday 8 February was the first day of the Lunar New Year, a national holiday across Asia.

By exploiting time differences between Bangladesh, New York and the Philippines, the hackers had engineered a clear five-day run to get the money away.

They had had plenty of time to plan all of this, because it turns out the Lazarus Group had been lurking inside Bangladesh Bank’s computer systems for a year.

In January 2015, an innocuous-looking email had been sent to several Bangladesh Bank employees. It came from a job seeker calling himself Rasel Ahlam. His polite enquiry included an invitation to download his CV and cover letter from a website. In reality, Rasel did not exist – he was simply a cover name being used by the Lazarus Group, according to FBI investigators. At least one person inside the bank fell for the trick, downloaded the documents, and got infected with the viruses hidden inside.

Once inside the bank’s systems, Lazarus Group began stealthily hopping from computer to computer, working their way towards the digital vaults and the billions of dollars they contained.

And then they stopped.

Why did the hackers only steal the money a whole year after the initial phishing email arrived at the bank? Why risk being discovered while hiding inside the bank’s systems all that time? Because, it seems, they needed the time to line up their escape routes for the money.

Jupiter Street is a busy thoroughfare in Manila. Next to an eco-hotel and a dental surgery is a branch of RCBC, one of the country’s largest banks. In May 2015, a few months after the hackers accessed Bangladesh Bank’s systems, four accounts were set up here by the hackers’ accomplices. In hindsight, there were some suspicious signs: the driver’s licences used to set up the accounts were fakes, and the applicants all claimed to have exactly the same job title and salary, despite working at different companies. But no-one seemed to notice. For months the accounts sat dormant with their initial $500 deposit untouched while the hackers worked on other aspects of the plan.

By February 2016, having successfully hacked into Bangladesh Bank and created conduits for the money, the Lazarus Group was ready.

But they still had one final hurdle to clear – the printer on the 10th floor. Bangladesh Bank had created a paper back-up system to record all transfers made from its accounts. This record of transactions risked exposing the hackers’ work instantly. And so they hacked into the software controlling it and took it out of action.

With their tracks covered, at 20:36 on Thursday 4 February 2016, the hackers began making their transfers – 35 in all, totalling $951m, almost the entire contents of Bangladesh Bank’s New York Fed account. The thieves were on their way to a massive payday – but just as in a Hollywood heist movie, a single, tiny detail would catch them out.

As Bangladesh Bank discovered the missing money over the course of that weekend, they struggled to work out what had happened. The bank’s governor knew Rakesh Asthana and his company, World Informatix, and called him in for help. At this point, Asthana says, the governor still thought he could claw back the stolen money. As a result, he kept the hack secret – not just from the public, but even from his own government.

Meanwhile, Asthana was discovering just how deep the hack went. He found out the thieves had gained access to a key part of Bangladesh Bank’s systems, called Swift. It’s the system used by thousands of banks around the world to co-ordinate transfers of large sums between themselves. The hackers didn’t exploit a vulnerability in Swift – they didn’t need to – so as far as Swift’s software was concerned the hackers looked like genuine bank employees.

It soon became clear to Bangladesh Bank’s officials that the transactions couldn’t just be reversed. Some money had already arrived in the Philippines, where the authorities told them they would need a court order to start the process to reclaim it. Court orders are public documents, and so when Bangladesh Bank finally filed its case in late February, the story went public and exploded worldwide.