The personal data of four million current and former government employees have been compromised by hackers in China,US officials said on Thursday, in one the largest thefts of government data in history.
US officials said that they have identified an attack targeting the Office of Personnel Management (OPM), which does most background checks for security clearances of federal employees, a process that often involves sensitive financial and personal information. Officials could not say exactly what was taken, only what the hackers had gained access to: Social Security numbers, job assignments, training and work performance ratings. The breach is believed to have happened in December.
The hackers were state-sponsored, anonymous officials told the Washington Post. A previous, smaller attack on the OPM last year was also traced back to China, according to officials. Chinese officials have not responded to the reports.
US officials have traced a number of hacking attacks on corporations and governments back to the People’s Liberation Army in recent years, and charged individual army officers and university professors with crimes.
Cyber security experts say the data could be used in “phishing” emails that trick recipients into opening a link or attachment, which then gives the hacker access to the recipient’s computer system. The stolen information could also be used to blackmail government workers or to impersonate them.