MalwareHealthcareHealthcareRansomwareData ExfiltratedCustomer Data InvolvedEmployee Data InvolvedPHIHealth (basic)Financial accountGovernment IDIdentity (basic)CriticalContained

Ascension Health Alliance

bd_eef1dcc9991ab11d · schema v1 · pii pii-v1

Severity

Critical

Discovered

May 8, 2024

Filed

Dec 17, 2025

To disclose

—

Affected · nationwide

5,466,93122,293 in this filing

Confidence

66%

Full breach record for Ascension Health Alliance →12 incidents on file

Ascension Health filed a supplemental security breach notification with the Maryland Office of the Attorney General on February 3, 2025, supplementing a December 19, 2024 filing. The incident involved a ransomware attack detected on May 8, 2024, affecting approximately 5.47 million individuals nationwide, including 22,293 Maryland residents. Exfiltrated data included PHI, financial account numbers, government IDs, and PII. Ascension engaged cybersecurity experts, notified the FBI and CISA, and provided 24 months of credit monitoring and ID theft recovery services.

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Incident timeline

undetected · 1 days

May 7, 2024

Begins

May 8, 2024

Discovered

Dec 17, 2025

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed5,466,931 affectedView incident

Name: Ascension Health Alliance
norm: ascension health alliance
Domain: ascension.org

Name: Ascension Health Alliance
norm: ascension health alliance
Domain: ascension.org
Industry: Healthcarellm

Discovered: May 8, 2024
Breach occurred: May 7, 2024 – May 8, 2024
Undetected for: 1 dayoccurrence → discovery
Materiality determined: —
Notification sent: Dec 19, 2024
Affected individuals: 5,466,931state + nationwide
Data types: PHIHealth (basic)Financial accountGovernment IDIdentity (basic)
Attack vector: Ransomware
MITRE ATT&CK: T1486 Data Encrypted for ImpactT1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Regulator citations: reported the incident to law enforcement and government partners, including the FBI and the Cybersecurity and Infrastructure Agency (CISA)

During the incident: Initiated an investigation with the assistance of leading cybersecurity experts
Reported the incident to law enforcement and government partners, including the FBI and the Cybersecurity and Infrastructure Agency (CISA)
Put in place additional monitoring to further protect its systems
Notified applicable Maryland residents of the security incident via United States Postal Service mail
Offered affected individuals 24 months of credit and CyberScan monitoring, a $1,000,000 insurance reimbursement policy, and fully managed ID theft recovery services through IDX
Changes made: Implemented enhanced security measures to prevent similar incidents from occurring in the future
Source: Quoted from the filing itself, not independently verified.

Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://oag.maryland.gov/resources-info/SBN%20Documents/2025/ITU-376048.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Dec 17, 2025
Raw hash: da011f954af9329443f1b2008b6253e0dc4b5cd917e786cabfeba3ff70299823

Reporting entityAscension Health Alliance

Victim entityAscension Health Alliance

Incidentdiscovered May 8, 2024

Stated responseInitiated an investigation with the assistance of leading cybersecurity experts

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenanceoag.maryland.gov