The Postal Service denied a Freedom of Information Act request from USA TODAY for the cease and desist letters, citing commercial trade secrets. USA TODAY has appealed the ruling.
The official line from the Postal Service is that it notified employees, monitored their compromised accounts, tried to recover their rerouted money and purchased a year of credit monitoring for them. It also said it warned all employees about cybercriminals.
Public affairs staff at the Postal Service declined requests from USA TODAY for an interview to answer questions about the causes and scope of the problems and the changes that followed.
In mid-January, however, the Postal Service rolled out its first multifactor authentication process for access to the HR site. That type of sign-in could have prevented many of the unauthorized account changes because it requires a user to confirm their identity via a second device, such as a smartphone.