Christus Health ransomware incident involved theft of sensitive patient and employee data

First, the good news (such as it is): a ransomware attack on Christus Health by Avos Locker has not impacted patient care. Now, the bad news: the threat actors acquired — and have already leaked — a lot of sensitive information on patients and employees.

On May 11, Avos Locker added Christus Health to their dark web leak site. The leak site contains a notice that all data on the leak site are available for sale if the owner does not pay.

In a statement provided to Information Security Media Group, CHRISTUS Health said it recently learned of “unauthorized activity” on its computer network.

“This was quickly identified and blocked by CHRISTUS information security. At this time, it appears that the incident is limited and didn’t impact any of CHRISTUS Health’s patient care or clinical operations. We are working with industry experts to investigate and address the issue. CHRISTUS values and is committed to the privacy and security of all those we are privileged to serve,” the statement says.

But note that an attack not impacting patient care does not mean the attack did not compromise patient or employee information. Inspection of the data leaked by the threat actors indicates that very sensitive information about patients and employees is in the hands of the threat actors.

DataBreaches inspected a sample of files in the leak. Here is a summary of just a few of the files:

  • a spreadsheet with the names of patients who tested positive for COVID-19 between March and June, 2020
  • a focused professional review of an employee included patient information from the case logs: patient name, date of service, diagnosis, and patient account number
  • admission records for a one-week period in 2019 that included patients’ names, date of birth, reason for admission, phone number, provider information, and health insurance information
  • an employee phone roster
  • a suspension letter to a named physician due to delinquent medical records
  • other letters to named physicians of the format:

This letter is to notify you that you have received a fourth (4th) suspension for the same delinquent medical record(s) in three consecutive months (September, October, November and December 2021). A copy of this letter will be placed in your Quality Management file for consideration by the Credentials Committee at the time of reappointment.

  • files with patients’ health insurance information and billings
  • a 17-page Operating Room Schedule dated 05/02/2022 with patient name, date of birth, phone number, medical record number, type of procedure, reason for visit, type of insurance, name of surgeon/anesthesiologist, and type of anesthesia. Each page had multiple patient records on it; and
  • a tumor conference patient list with information on six patients for consideration at a July 2020 case conference. Each patient’s name, date of birth, social security number, and type of tumor issue, was included.

Again, that is just a small sample, but it’s clear that the threat actors acquired files with sensitive medical information on patients and sensitive personnel information. What else they got and how much they got is as yet unknown.

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