The FBI on Thursday issued a public notice warning U.S. businesses of attempts by North Korean hackers to extort data and hold stolen proprietary data and code hostage until the companies involved meet ransom demands.

"North Korean IT workers have copied company code repositories, such as GitHub, to their own user profiles and personal cloud accounts. While not uncommon among software developers, this activity represents a large-scale risk of theft of company code," the FBI said.

The warning adds that North Korean IT workers "could attempt to harvest sensitive company credentials and session cookies to initiate work sessions from non-company devices and for further compromising opportunities."

The report comes a month after 14 men with ties to North Korea's government were charged in federal court with involvement in a scheme that used remote IT workers to funnel $88 million to the country's nuclear weapons program.

"To prop up its brutal regime, the North Korean government directs IT workers to gain employment through fraud, steal sensitive information from U.S. companies, and siphon money back to the DPRK [Democratic People's Republic of Korea]," Deputy U.S. Attorney General Lisa Monaco said of the scheme.

"This indictment of 14 North Korean nationals exposes their alleged sanctions evasion and should serve as a warning to companies around the globe — be on alert for this malicious activity by the DPRK regime."

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