Executive Summary

On December 22, 2025, Nissan Motor Co., Ltd. disclosed a data breach impacting approximately 21,000 customers. This was a supply chain incident, where the breach did not occur on Nissan's core systems but on a third-party server managed by Red Hat. The compromised system was a GitLab server used by a contractor for software development related to a dealership customer management system. The breach, initially detected by Red Hat in late September, exposed customer PII including names, addresses, and phone numbers. The incident highlights the significant risks associated with third-party vendors and the software development lifecycle. The threat actor groups Crimson Collective and ShinyHunters have been associated with the attack.

Threat Overview

The attack chain began with the compromise of Red Hat's infrastructure, an incident claimed by a group called 'Crimson Collective.' The notorious extortion group ShinyHunters later became involved, publicizing data samples to pressure victims. The unauthorized access on Red Hat's systems was first detected on September 26, 2025. The compromised asset was a GitLab server used for developing a customer management system for Nissan Fukuoka Sales Co., Ltd. On October 3, 2025, Red Hat notified Nissan of the breach. The exposed data pertains to customers who purchased vehicles or received services from that specific dealership. Nissan has confirmed that sensitive financial data like credit card numbers was not stored on the affected server and was not compromised.

Technical Analysis

The breach originated from a compromised software development environment, a common vector for supply chain attacks.

TTPs and MITRE ATT&CK Mapping

• T1199 - Trusted Relationship: The attackers exploited the trusted relationship between Nissan and its third-party contractors (Red Hat and the development firm). By compromising the vendor, they gained access to Nissan's data.
• T1190 - Exploit Public-Facing Application: It is likely the attackers gained initial access to the GitLab server by exploiting a vulnerability in the platform or its associated services.
• T1552.006 - Unsecured Credentials: Git Roles: Once on the server, attackers could have accessed data by exploiting misconfigured permissions or unsecured credentials within the GitLab repositories.
• T1530 - Data from Cloud Storage Object: The attackers exfiltrated customer data that was stored or processed within the compromised development environment.

Impact Assessment

The direct impact is the exposure of personal information for 21,000 Nissan customers, placing them at risk of phishing, smishing, and other social engineering attacks. For Nissan, the incident causes significant reputational damage and erodes customer trust, despite the breach occurring at a third party. It also necessitates a costly response, including customer notification, credit monitoring services, and regulatory reporting to Japan's Personal Information Protection Commission. For Red Hat, the incident damages its reputation as a secure service provider. The event underscores the principle that an organization can outsource services, but it cannot outsource the ultimate responsibility for protecting its data.

Detection & Response

1. Third-Party Monitoring: Continuously monitor and audit logs from third-party managed systems, especially those handling sensitive data. Insist on access to security logs as part of vendor contracts.
2. Code Repository Auditing: Regularly audit code repositories like GitLab for anomalous activity, such as large data clones, access from unusual IP addresses, or unexpected changes in user permissions.
3. Incident Response Plan: Ensure incident response plans explicitly cover supply chain incidents, with clear protocols for communication and data sharing with affected vendors and customers.
4. D3FEND Techniques: Implement D3-RAPA: Resource Access Pattern Analysis to detect deviations from normal developer access patterns within the GitLab environment. Use D3-UGLPA: User Geolocation Logon Pattern Analysis to flag suspicious logins to developer accounts.

Mitigation

1. Vendor Risk Management: Implement a robust vendor risk management program. This includes thorough security assessments before onboarding, contractual requirements for security controls and breach notification, and regular audits.
2. Data Minimization: Enforce data minimization principles with third parties. Contractors should only have access to the absolute minimum data required for their function. Production customer PII should not be used in development environments.
3. Secure Software Development Lifecycle (SSDLC): Mandate that all third-party developers adhere to a secure SDLC. This includes code scanning (SAST/DAST), dependency checking, and secure configuration of development tools like GitLab.
4. Strong Authentication: Enforce multi-factor authentication (MFA) for all access to development platforms and code repositories for both internal employees and third-party contractors.
5. D3FEND Countermeasures: Harden development environments using D3-ACH: Application Configuration Hardening for tools like GitLab. Enforce strict D3-UAP: User Account Permissions to ensure developers cannot access data beyond their specific project scope.