
By Cory Bennett – 06/04/15 05:17 PM EDT
Roughly 4 million current and former federal employees have had their data exposed by a hack, the Obama administration said Thursday.
The notification from the Office of Personnel Management (OPM) was short on details, but it appears troves of sensitive information had been pilfered.
Separate media reports cited China as being behind the massive hack.
The digital assailants first infiltrated the system in December, four months before they were discovered, The Washington Post reported.
“Protecting our Federal employee data from malicious cyber incidents is of the highest priority at OPM,” said OPM Director Katherine Archuleta. “We take very seriously our responsibility to secure the information stored in our systems.”
The FBI said it had opened up an investigation into the breach, which The Wall Street Journalreported is believed to have come from hackers in China.
An unnamed U.S. official told NBCNews that the data breach might touch every federal agency.
A Department of Homeland Security spokesman said it noticed “malicious activity affecting its information technology (IT) systems and data in April.”