Amazon says blocked 1,800 North Koreans from applying for jobs

He said the firm had seen nearly a one-third rise in applications by North Koreans in the past year.

The North Koreans typically use "laptop farms" -- a computer in the United States operated remotely from outside the country, he said.

He warned the problem wasn't specific to Amazon and "is likely happening at scale across the industry".

Tell-tale signs of North Korean workers, Schmidt said, included wrongly formatted phone numbers and dodgy academic credentials.

In July, a woman in Arizona was sentenced to more than eight years in prison for running a laptop farm helping North Korean IT workers secure remote jobs at more than 300 US companies.

The scheme generated more than $17 million in revenue for her and North Korea, officials said.

Last year, Seoul's intelligence agency warned that North Korean operatives had used LinkedIn to pose as recruiters and approach South Koreans working at defence firms to obtain information on their technologies.

"North Korea is actively training cyber personnel and infiltrating key locations worldwide," Hong Min, an analyst at the Korea Institute for National Unification, told AFP.  

"Given Amazon's business nature, the motive seems largely economic, with a high likelihood that the operation was planned to steal financial assets," he added.

North Korea's cyber-warfare programme dates back to at least the mid-1990s.

It has since grown into a 6,000-strong cyber unit known as Bureau 121, which operates from several countries, according to a 2020 US military report.

In November, Washington announced sanctions on eight individuals accused of being "state-sponsored hackers", whose illicit operations were conducted "to fund the regime's nuclear weapons programme" by stealing and laundering money.

The US Department of the Treasury has accused North Korea-affiliated cybercriminals of stealing over $3 billion over the past three years, primarily in cryptocurrency.

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