INCIDENT REPORT · CP-2024-004
Ascension health system ransomware attack
L3 · ELEVATEDCONFIRMED
Ascension, one of the largest US nonprofit health systems, suffered a ransomware attack in May 2024 that disrupted clinical IT systems across its hospitals.
- Incident ID
- CP-2024-004
- Incident date
- 08 MAY 2024
- Detection date
- 08 MAY 2024
- Affected countries
- United States
- Plotted location
- St. Louis, United States (Affected organization headquarters)
- Threat classification
- Level 3 — ELEVATED
- Classification rationale
- Multi-state disruption of a large hospital network with millions of records stolen.
- Attack type
- Ransomware
- Nature
- Malicious activity
- Attack vector
- An employee accidentally downloaded a malicious file (per Ascension's June 2024 statement)
- Sectors
- Healthcare
- Critical infrastructure
- Yes
- Organizations affected
- Ascension
- Operational consequences
- Clinical operations were disrupted and attackers stole files from seven of about 25,000 servers. In December 2024 Ascension began notifying nearly 5.6 million patients and employees that their data was affected.
- Estimated financial impact
- No reliably documented figure
- Attribution (as stated)
- No official attribution recorded
SOURCE REFERENCES
- [1] 5.6 Million Impacted by Ransomware Attack on Healthcare Giant AscensionSecurityWeek · securityweek.com
- [2] Ascension Notifying 5.6 Million Affected by Ransomware HackGovInfoSecurity · govinfosecurity.com
RECORD CREATED 14 NOV 2026 · LAST UPDATED 14 NOV 2026 · Threat levels are editorial assessments, not official government ratings.