The U.S. government has opened a probe into China-based hackers who targeted files of employees applying for top-secret security clearances. The hackers reportedly managed to access the computer network of the government in mid-March.
A senior Department of Homeland Security (DHS) official confirmed the attacks, but had no information to offer on the extent of the attack, or whether personal data was stolen from the United States' Office of Personnel Management.
According to the New York Times, the hackers were able to access some of the databases storing the personal information of all federal employees.
Upon further investigation, the DHS traced that the hackers were located in China. The investigators were uncertain whether the hackers were members of the Chinese government.
The Chinese and U.S. governments are locked in an ongoing conflict about computer intrusions, after former National Security Agency (NSA) contractor Edward Snowden revealed that the U.S. security agency hacked Huawei's computer systems and installed programs to intercept conversations of the Chinese leaders and military personnel.
Last month, Chinese hackers from the People's Liberation Army (PLA) Unit 61398 were charged by the Justice Department for stealing corporate secrets. The same PLA unit and others like it were also accused of snooping into the U.S. government's computers in the past.
The U.S. government warned the public and other businesses to announce any security breach detected, as hackers no longer send warnings prior to their attacks.
"The administration has never advocated that all intrusions be made public," said Caitlin Hayden, a spokeswoman for the Obama administration, quoted by the New York Times. "We have advocated that businesses that have suffered an intrusion notify customers if the intruder had access to consumers' personal information. We have also advocated that companies and agencies voluntarily share information about intrusions."