Geisinger Breach Incident Score: Analysis & Impact (GEI4702447112225)

In this Rankiteo incident briefing, we review the Geisinger breach identified under incident ID GEI4702447112225.

The analysis begins with a detailed overview of Geisinger's information like the linkedin page: https://www.linkedin.com/company/geisinger, the number of followers: 83823, the industry type: Hospitals and Health Care and the number of employees: 15443 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 735 and after the incident was 629 with a difference of -106 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 Geisinger and their customers.

Geisinger Health recently reported "Geisinger Health and Nuance Communications Data Breach (2023)", a noteworthy cybersecurity incident.

A former Nuance Communications employee accessed and potentially obtained sensitive patient information from Geisinger Health, impacting over 1 million individuals.

The disruption is felt across the environment, and exposing Names, Dates of Birth and Addresses, with nearly 1,000,000+ records at risk, plus an estimated financial loss of $5 million (settlement).

In response, teams activated the incident response plan, moved swiftly to contain the threat with measures like Termination of employee (pre-incident) and Delayed notification per law enforcement, while recovery efforts such as Patient notifications sent by Nuance on behalf of Geisinger continue, and stakeholders are being briefed through Class action settlement notifications and Public disclosure via legal proceedings.

The case underscores how Ongoing (final approval hearing scheduled for 2026-03-16), teams are taking away lessons such as Insider threats pose significant risks in healthcare; timely termination and access revocation are critical. Delayed breach notifications can complicate legal and reputational responses, and recommending next steps like Enhance insider threat detection programs, Implement stricter access controls for sensitive data and Conduct regular audits of employee access to PHI/PII, with advisories going out to stakeholders covering Class action settlement notices and Federal investigation updates.

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.

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: Cloud Accounts (T1078.004) with high confidence (95%), supported by evidence indicating authorized internal access (former employee) with accessed and potentially exfiltrated data. Under the Credential Access tactic, the analysis identified Valid Accounts (T1078) with high confidence (95%), supported by evidence indicating former Nuance employee retained access post-termination; accessed and potentially obtained PHI/PII. Under the Collection tactic, the analysis identified Data from Local System (T1005) with high confidence (90%), supported by evidence indicating accessed and potentially obtained PII/PHI including Medical Record Numbers, Admit/Discharge Codes. Under the Exfiltration tactic, the analysis identified Exfiltration Over Alternative Protocol (T1048) with moderate to high confidence (85%), supported by evidence indicating potentially exfiltrated 1M+ records; no evidence of encryption/ransomware and Automated Exfiltration (T1020) with moderate to high confidence (80%), supported by evidence indicating large-scale data access (1M+ records) suggests automated collection/exfiltration. Under the Impact tactic, the analysis identified Data Destruction (T1485) with lower confidence (10%), supported by evidence indicating no direct evidence, but high-risk PII/PHI exposure implies potential misuse, Data Encrypted for Impact (T1486) with lower confidence (5%), supported by evidence indicating no ransomware mentioned; included only for completeness (low confidence), and Malicious Activity Following Termination (T1659) with high confidence (95%), supported by evidence indicating terminated just two days before the incident; accessed data post-termination. Under the Defense Evasion tactic, the analysis identified Indicator Removal: File Deletion (T1070.004) with moderate to high confidence (70%), supported by evidence indicating no explicit logs/evidence mentioned; insider may have cleared access trails and Impair Defenses: Disable or Modify Tools (T1562.001) with moderate confidence (60%), supported by evidence indicating insufficient controls to prevent unauthorized access suggests possible defense bypass. Under the Persistence tactic, the analysis identified Account Manipulation: Additional Cloud Credentials (T1098.003) with moderate to high confidence (85%), supported by evidence indicating former employee retained access post-termination; no MFA/access revocation mentioned. These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.