California Casualty Breach Incident Score: Analysis & Impact (CAL5692756112025)

In this Rankiteo incident briefing, we review the California Casualty breach identified under incident ID CAL5692756112025.

The analysis begins with a detailed overview of California Casualty's information like the linkedin page: https://www.linkedin.com/company/california-casualty, the number of followers: 11812, the industry type: Insurance and the number of employees: 559 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 695 and after the incident was 628 with a difference of -67 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 California Casualty and their customers.

On 19 November 2025, California Casualty Indemnity Exchange disclosed Data Breach issues under the banner "California Casualty Indemnity Exchange Data Breach (2025)".

California Casualty Indemnity Exchange, a customer-owned insurance company serving educators, law enforcement, firefighters, and nurses, experienced a data breach exposing sensitive personal information of some policyholders.

The disruption is felt across the environment, and exposing Names, Social Security Numbers and Dates of Birth, with nearly At least 5 (exact total unspecified) records at risk.

In response, teams activated the incident response plan, moved swiftly to contain the threat with measures like Isolation of certain IT systems, while recovery efforts such as Complimentary 24-month Experian IdentityWorks memberships (credit monitoring, identity theft detection, and restoration) and Dedicated toll-free call center for breach-related inquiries continue, and stakeholders are being briefed through Written notification letters mailed to affected consumers (starting Nov. 19, 2025) and Advisories for affected individuals to review account statements, obtain free credit reports, and consider fraud alerts/security freezes.

The case underscores how Completed (as of Nov. 5, 2025), and recommending next steps like Affected individuals should activate complimentary Experian IdentityWorks memberships, Regularly review account statements and credit reports for suspicious activity and Consider placing fraud alerts or security freezes on credit files, with advisories going out to stakeholders covering Notification letters with instructions for activating Experian IdentityWorks and Guidance on monitoring accounts, obtaining credit reports, and placing fraud alerts/security freezes.

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 (T1078) with moderate to high confidence (70%), with evidence including attack vector such as Unauthorized Network Access, and threat actor such as Unauthorized Individual and External Remote Services (T1133) with moderate confidence (60%), with evidence including accessed its IT network between September 2–8, 2025, and unauthorized Network Access. Under the Collection tactic, the analysis identified Data from Local System (T1005) with high confidence (95%), with evidence including copying files containing sensitive PII such as SSNs, financial account details, and data exfiltration such as true. Under the Exfiltration tactic, the analysis identified Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted/Obfuscated Non-C2 Protocol (T1048.003) with moderate to high confidence (85%), with evidence including copying files containing sensitive PII, and unauthorized data exfiltration of customer PII and Automated Exfiltration (T1020) with moderate to high confidence (70%), supported by evidence indicating copying files suggests automated collection prior to exfiltration. Under the Impact tactic, the analysis identified Data Destruction (T1485) with lower confidence (5%), supported by evidence indicating no ransomware reported, but data exfiltration confirmed (low-confidence placeholder) and Identity Theft (T1659) with high confidence (95%), with evidence including exposure of SSNs, financial data puts individuals at risk of identity theft, and high (due to exposure of PII). Under the Defense Evasion tactic, the analysis identified Indicator Removal: File Deletion (T1070.004) with moderate confidence (50%), supported by evidence indicating no direct evidence, but delayed detection (Sept 2–8 breach, discovered Nov 5) suggests possible log/trace cleanup and Impair Defenses: Disable or Modify Tools (T1562.001) with lower confidence (40%), supported by evidence indicating isolation of certain IT systems during investigation implies potential tampering with defenses pre-discovery. Under the Credential Access tactic, the analysis identified Unsecured Credentials: Credentials In Files (T1552.001) with moderate to high confidence (70%), supported by evidence indicating copying files may include credential stores (implied by access to PII/financial systems). These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.