An unauthorized party has removed files containing patients' personal information from Hayward, Calif.-based St. Rose Hospital, JDSupra reported Jan. 13.
On Nov. 29, the hospital detected suspicious activity within its computer network and launched an investigation into the incident.
The investigation confirmed that an unauthorized party was able to access its computer network on Nov. 18 and removed files from its computer system that contained patient information such as names, Social Security numbers, dates of birth, email addresses and home addresses.
The hospital has since filed a notice of a data breach with the Attorney General of California and mailed letters to all affected patients on Jan. 12.
It is unknown how many individuals are affected by the breach.