The United States Postal Service (USPS) has shut down employee VPN (virtual private network) access and suspended telecommuting until further notice for employees at Postal Service headquarters.
USPS Media Relations Manager David Partenheimer told SecurityWeek via email that while VPN is out nationwide, the suspension of telecommuting does not affect a huge number of employees.
"The employees impacted generally only telecommute one or two days per week and they will now be required to report to their work station," he explained. "This isn’t like other agencies that have mass employees working from home or from alternate locations with no work station assigned - our employees have cubes or offices assigned to them on a permanent basis."
On Monday, USPS revealed it was victimized in an attack and is working with the FBI and other agencies to investigate the situation. The attack compromised personally-identifiable information about all active employees, including names, social security numbers, dates of birth and other information. The intrusion also compromised call center data for customers who contacted the Postal Service Customer Care Center by phone or email between Jan. 1 and August 16.
In a FAQ for employees dated Nov. 10, the postal service stated that VPN access was identified as being vulnerable to intrusion and would be unavailable as USPS makes modifications.
"Through the investigation we identified the methods and locations that were used to gain access to some of our data systems and devised a plan to close those access routes to our infrastructure to prevent future intrusions," according to the FAQ. "Additionally, we are instituting numerous additional security measures, some of which are equipment and system upgrades that will not be visible to any users, and some of which are changes in policies and procedures that we will be rolling out in the coming days and weeks."
To improve security, the postal service performed maintenance and upgrades of its computer and information systems during the weekend of Nov. 8 and 9, taking some systems offline. This allowed the organization to eliminate certain system vulnerabilities.
In a statement issued Nov. 10, Partenheimer explained the USPS transactional revenue systems in post offices as well as on usps.com where customers pay for services with credit and debit cards have not been affected by the incident. There is also no evidence that any customer credit card information from retail or online purchases such as Click-N-Ship, the Postal Store, PostalOne!, change of address or other services was compromised.
"The privacy and security of data entrusted to us is of the utmost importance," he noted. "We have recently implemented additional security measures designed to improve the security of our information systems, including certain actions this past weekend that caused certain systems to be off-line. We know this caused inconvenience to some of our customers and partners, and we apologize for any disruption."
In a statement, American Postal Workers Union (APWU) President Mark Dimondstein said the union leadership was in the dark about the breach despite the Postal Service knowing about it for months.
"Unfortunately, cybercrime is real and effective," he wrote. "But we are outraged that this happened. We do not know at this point whether management did everything in their power to protect our privacy, but they bear the ultimate responsibility."
So far, the Postal Service said it has not uncovered evidence of any employee or customer data being used maliciously. While the investigation is ongoing, the Washington Post reported that suspicion has fallen on hackers backed by the Chinese government. The intrusion was first discovered in mid-September, according to the paper.