Hackers successfully targeted the U.S. Postal Service in September, compromising the personal data of approximately 800,000 USPS employees.
The agency informed Congress about the breach in classified briefings on Oct. 22 and Nov. 7, USA Today reported Monday.
The “issue is still under investigation,” an agency spokeswoman told USA Today. The investigation is being led by the FBI.
“It is an unfortunate fact of life these days that every organization connected to the Internet is a constant target for cyber intrusion activity,” said Postmaster General Patrick Donahoe in a statement.
The hack also affected USPS customers who contacted the service’s Customer Care Center, according to the Associated Press. The information potentially accessed includes telephone numbers, email addresses and addresses.
The Washington Post reported Monday that China is suspected of being behind the attack.
“They’re just looking for big pots of data on government employees,” a cyber-policy expert told the Post. “For the Chinese, this is probably a way of building their inventory on U.S. persons for counterintelligence and recruitment purpose.”
