MCBS Breach Affects 1.26 Million People
Summary
MCBS reported attackers accessed its systems in September 2025. A US HHS tracker lists 1,261,464 affected people; files containing personal and medical information may have been stolen. PEAR separately claimed responsibility.
Key points
- MCBS said attackers accessed its systems from September 22 to 26, 2025.
- The investigation found files potentially containing names, addresses, Social Security numbers, birth dates, insurance details, and medical information.
- The US HHS breach tracker lists 1,261,464 affected individuals; MCBS’s notification names seven healthcare organizations whose data was compromised.
- The PEAR ransomware group claimed it stole more than 3 TB of files, including patient and business information.
- PEAR’s claim is distinct from the investigation’s findings; the article says the allegedly stolen information was made available for download.
Article Details
- Victim Organization
- MCBS (Medical Computer Business Services)
- Incident Type
- Data breach involving unauthorized access to MCBS systems and potential theft of files
- Incident Date
- 2025-09-22
- Data Types Exposed
- Names
- Addresses
- Social Security numbers
- Dates of birth
- Health insurance information
- Medical information
- Affected Records
- 1,261,464 individuals, according to the US Department of Health and Human Services healthcare data breach tracker
- Affected Data Size
- The PEAR ransomware group claimed to have stolen more than 3 TB of files; this claim was not independently confirmed in the article.
- Ransom Or Extortion
- PEAR claimed responsibility and allegedly made the stolen information available for download. No ransom demand or payment was reported.
- Claim Status
- confirmed