By Aruna Viswanatha and Dustin Volz 

This article is being republished as part of our daily reproduction of WSJ.com articles that also appeared in the U.S. print edition of The Wall Street Journal (September 7, 2018).

The U.S. announced charges against a North Korean operative in connection with cyberattacks including the 2014 Sony Pictures hack and a global ransomware attack last year, intensifying pressure against a cyber army that has morphed into one of the world's most sophisticated hacking operations.

Park Jin Hyok was accused in a criminal complaint dated June 8 but unsealed Thursday of working with other unnamed co-conspirators to conduct a series of cyberattacks on corporate and financial networks to steal money and information at the direction of the North Korean government.

Prosecutors also accused Mr. Park of playing a role in the theft of $81 million from Bangladesh's account at the Federal Reserve Bank of New York in 2016, which prosecutors said was the largest ever successful cybertheft from a financial institution.

The case, the first to explicitly target North Korean state-backed hackers, was filed days before President Trump's June 12 summit with North Korea's leader in Singapore.

Justice Department officials declined to comment on why the case wasn't made public until nearly three months after it was filed, saying only that decision on timing involve multiple factors including when a case might have the "greatest impact."

The case comes as U.S.-North Korea denuclearization talks have reached a standstill, and the State Department said Thursday that a former Ford Motor Co. executive recently tapped to pursue negotiations with North Korea will travel to Asia next week.

Stephen Biegun, named Special Representative for North Korea by Secretary of State Mike Pompeo, will travel to Seoul, Tokyo and Beijing between Sept. 10 and Sept. 15, although officials didn't announce any travel by Mr. Biegun to North Korea.

A South Korean delegation met with North Korean leader Kim Jong Un earlier this week and said Mr. Kim was interested in rekindling talks and told the South Koreans he had faith in Mr. Trump. Mr. Trump, in reply, tweeted Thursday: "Thank you to Chairman Kim. We will get it done together!"

The complaint alleges Mr. Park worked with others in persistent attempts to carry out the cyberattacks between 2014 and through this year. Those include efforts to hack into and steal money from banks in the U.S. and several other countries with attempted thefts of more than $1 billion, prosecutors said.

"Working for a foreign government does not immunize criminal conduct," John Demers, who runs the Justice Department's national security division, said at a briefing about the case. "These activities run afoul of norms of acceptable state behavior in cyberspace," Mr. Demers said, urging the "international community" to take action.

Prosecutors said they gathered evidence of Mr. Park's alleged crimes by analyzing compromised computers and executing about 100 search warrants to access more than 1,000 email and social-media accounts. Investigators said they issued 85 formal requests from foreign countries for evidence from communications providers.

Mr. Park had been living in China and working for a North Korean front company called Chosun Expo that is affiliated with one of the government's hacking organizations, sometimes referred to as Lab 110, prosecutors said. He appeared to return to North Korea shortly before the 2014 Sony breach, the complaint said.

As part of Thursday's actions, the Treasury Department levied financial sanctions on Mr. Park and Chosun Expo, describing Chosun as an entity controlled by North Korea.

Mr. Park is believed to be in North Korea and couldn't be located for comment.

Soon after the Sony breach, which exposed thousands of embarrassing emails between executives and led the studio to pull the movie "The Interview" from theaters, the FBI publicly identified North Korea as the likely perpetrator.

The movie involved a satirical plot to kill North Korean leader Kim Jong Un. The new complaint said the hackers also targeted AMC Theatres, which was scheduled to release and show "The Interview," sending sophisticated spear-phishing messages to multiple AMC employees.

The U.S. case comes as North Korea built a cyberarmy that has about 7,000 hackers and support staffers.

The team described in the complaint, often called "Lazarus" by private security researchers, is known to attack foreign entities and has previously been associated with North Korea's most headline-grabbing campaigns. Those included the Sony attack and last year's WannaCry ransomware, which locked digital files on hundreds of thousands of computers and demanded bitcoin payment for their release. The new cases throws the weight of the U.S. government squarely behind those assessments.

The Justice Department has previously brought similar hacking cases against Chinese, Iranian and Russian hackers, but most of the defendants remain overseas. The goal of such cases, officials say, is to publicly expose the hackers and try to deter such activities.

Senior officials have conceded there is little they can do to deter North Korea from using hacking tools to support its regime, in part because it is already under heavy sanctions and has no compunction about being shamed for its activities.

After the Sony breach, then-President Obama was alarmed at how it had the effect of chilling free speech in the U.S. by forcing Sony to not show "The Interview" in theaters.

"We cannot have a society in which some dictator someplace can start imposing censorship here in the United States," Mr. Obama said at the time.

Since then, North Korea has only become more emboldened to use its cyberarsenal, and has developed more sophisticated capabilities, experts say. They include the theft of bitcoin and other cryptocurrencies to enrich its regime.

Last December, the White House publicly blamed Pyongyang for unleashing the WannaCry worm, an unprecedented cyberattack that infected more than 300,000 computers in more than 150 countries, crippling banks, hospitals and other companies.

The Federal Bureau of Investigation and the Department of Homeland Security also issued public alerts last year warning that hackers working for the North Korean government had been targeting critical infrastructure in the U.S. as well as the media, aerospace and financial sectors, in a campaign of attacks dating back to 2009.

Some doubted the charges would have any real-world practical effect or signaled a broader strategy from the Trump administration on how to combat state-sponsored cyberthreats.

The charges were "cute, but ineffective," said Blake Darche, a former National Security Agency hacker. "The attacks will continue," said Mr. Darche, co-founder of the cyber firm Area 1 Security.

Write to Aruna Viswanatha at Aruna.Viswanatha@wsj.com

(END) Dow Jones Newswires

September 07, 2018 02:47 ET (06:47 GMT)