Incident Score: Analysis & Impact (NOR1773081145)
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Rankiteo Score Impact Analysis
Key Highlights From The Incident Analysis
- Timeline of Northwestern Medicine's Breach and lateral movement inside company's environment.
- Overview of affected data sets, including SSNs and PHI, and why they materially increase incident severity.
- How Rankiteo’s incident engine converts technical details into a normalized incident score.
- How this cyber incident impacts Northwestern Medicine Rankiteo cyber scoring and cyber rating.
- Rankiteo’s MITRE ATT&CK correlation analysis for this incident, with associated confidence level.
Full Incident Analysis Transcript
In this Rankiteo incident briefing, we review the Northwestern Medicine breach identified under incident ID NOR1773081145.
The analysis begins with a detailed overview of Northwestern Medicine's information like the linkedin page: https://www.linkedin.com/company/northwestern-medicine, the number of followers: 133076, the industry type: Hospitals and Health Care and the number of employees: 15525 employees
After the initial compromise, the video explains how Rankiteo's incident engine converts technical details into a normalized incident score. The incident score before the incident was 758 and after the incident was 707 with a difference of -51 which is could be a good indicator of the severity and impact of the incident.
In the next step of the video, we will analyze in more details the incident and the impact it had on Northwestern Medicine and their customers.
On 20 May 2025, Northwestern Memorial HealthCare (NMH) disclosed Data Breach issues under the banner "NMH Data Breach Affecting Sensitive Personal and Health Information".
Northwestern Memorial HealthCare (NMH) disclosed a data breach in which unauthorized access to sensitive personal identifiable information (PII) and protected health information (PHI) may have occurred.
The disruption is felt across the environment, affecting NMH Network, and exposing Sensitive personal identifiable information (PII) and protected health information (PHI).
In response, teams activated the incident response plan, and stakeholders are being briefed through Breach notice published on website and notification letters mailed to affected individuals.
The case underscores how Completed, with advisories going out to stakeholders covering Complimentary credit monitoring services offered to California residents.
Finally, we try to match the incident with the MITRE ATT&CK framework to see if there is any correlation between the incident and the MITRE ATT&CK framework.
The MITRE ATT&CK framework is a knowledge base of techniques and sub-techniques that are used to describe the tactics and procedures of cyber adversaries. It is a powerful tool for understanding the threat landscape and for developing effective defense strategies.
MITRE ATT&CK® Correlation Analysis
Rankiteo's analysis has identified several MITRE ATT&CK tactics and techniques associated with this incident, each with varying levels of confidence based on available evidence. Under the Initial Access tactic, the analysis identified Valid Accounts (T1078) with moderate to high confidence (70%), supported by evidence indicating unauthorized third party accessed its network between March 19 and May 20, 2025 and Exploit Public-Facing Application (T1190) with moderate confidence (50%), supported by evidence indicating unauthorized access to sensitive personal identifiable information (PII) and PHI. Under the Credential Access tactic, the analysis identified Unsecured Credentials (T1552) with moderate confidence (60%), supported by evidence indicating social Security numbers, full names, and health insurance details compromised and OS Credential Dumping (T1003) with moderate confidence (50%), supported by evidence indicating unauthorized access to NMH network with high sensitivity data. Under the Discovery tactic, the analysis identified Account Discovery (T1087) with moderate confidence (60%), supported by evidence indicating personal and medical data exposed, including full names and medical records and File and Directory Discovery (T1083) with moderate to high confidence (70%), supported by evidence indicating sensitive PII and PHI accessed over two-month period. Under the Collection tactic, the analysis identified Data from Local System (T1005) with moderate to high confidence (80%), supported by evidence indicating social Security numbers, addresses, dates of birth, medical records compromised and Data from Information Repositories (T1213) with moderate to high confidence (70%), supported by evidence indicating protected health information (PHI) and personal identifiable information (PII) exposed. Under the Exfiltration tactic, the analysis identified Exfiltration Over C2 Channel (T1041) with moderate to high confidence (70%), supported by evidence indicating unauthorized third party accessed its network for over two months and Transfer Data to Cloud Account (T1537) with moderate confidence (50%), supported by evidence indicating high sensitivity data (PII/PHI) compromised without detection for weeks. Under the Impact tactic, the analysis identified Data Destruction (T1485) with lower confidence (30%), supported by evidence indicating no details on extent of breach or data integrity post-incident and Data Manipulation: Stored Data Manipulation (T1565.001) with lower confidence (40%), supported by evidence indicating potential long-term identity theft risks for impacted individuals. These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.
Sources & References
- Northwestern Medicine Rankiteo Cyber Incident Details: https://www.rankiteo.com/company/northwestern-medicine/incident/NOR1773081145
- Northwestern Medicine CyberSecurity Rating page: https://www.rankiteo.com/company/northwestern-medicine
- Northwestern Medicine Rankiteo Cyber Incident Blog Article: https://blog.rankiteo.com/nor1773081145-northwestern-memorial-healthcare-breach-march-2025/
- Northwestern Medicine CyberSecurity Score History: https://www.rankiteo.com/company/northwestern-medicine/history
- Northwestern Medicine CyberSecurity Incident Source: https://straussborrelli.com/2026/03/09/northwest-medical-homes-data-breach-investigation/
- Rankiteo A.I CyberSecurity Rating methodology: https://www.rankiteo.com/Images/rankiteo_algo.pdf
- Rankiteo TPRM Scoring methodology: https://static.rankiteo.com/model/rankiteo_tprm_methodology.pdf