The cyber attack caused serious print and print failures on Saturday in the Los Angeles Times and other major American newspapers, including those owned by Tribune Publishing Co, such as the Chicago Tribune and Baltimore Sun.
The Los Angeles Times reported that a cyber attack occurred outside the United States, citing a source aware of the situation.
According to the Los Angeles Times, the attack caused distribution delays in the Saturday edition of The Times, Tribune, Sun, and other newspapers that use a common production platform in Los Angeles.
Tribune Publishing, whose newspapers also include the New York Daily News and Orlando Sentinel, said it first discovered malware on Friday.
The Wall Street Journal and the New York Times on the West Coast were amazed, as they were also printed on a common production platform, the Los Angeles Times reported.
US authorities are investigating
Tribune Publishing spokeswoman Marisa Collias said the virus damaged the back-office systems that were used to publish and produce "newspapers all over our property."
“There is no evidence that customer’s credit card information or personal information was compromised,” Collias said in a statement.
The Wall Street Journal and the New York Times did not immediately respond to requests for comment.
The majority of San Diego Union-Tribune subscribers didn’t have a newspaper on Saturday because the virus infected the company's business systems and limited its ability to publish, Jeff Light, the editor and publisher of the newspaper, writes on his website.
A spokesman for the US Department of Homeland Security said he was studying the situation.
“We are aware of reports of a possible cyber incident affecting several news agencies, and we are working with our government and industry partners to better understand the situation,” said DHS spokeswoman Katie Waldman.