EUVD-2025-19634

Comprehensive Technical Analysis of EUVD-2025-19634

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-19634 pertains to a cloud infrastructure misconfiguration in the OneLogin AD Connector. This misconfiguration results in log data being sent to a hardcoded S3 bucket (onelogin-adc-logs-production) without validating bucket ownership. The severity of this vulnerability is rated with a Base Score of 9.0 using CVSS version 4.0, indicating a critical issue. The vector string CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N highlights the following:

• Attack Vector (AV:N): Network, meaning the vulnerability is exploitable remotely.
• Attack Complexity (AC:L): Low, indicating that the attack does not require specialized conditions.
• Authentication (AT:P): Partial, suggesting that some level of authentication is required, but it is not fully enforced.
• Privileges Required (PR:N): None, meaning no special privileges are needed to exploit the vulnerability.
• User Interaction (UI:N): None, indicating that no user interaction is required.
• Confidentiality Impact (VC:H): High, suggesting significant confidentiality breach.
• Integrity Impact (VI:L): Low, indicating minimal integrity impact.
• Availability Impact (VA:N): None, meaning no impact on availability.
• Scope Change (SC:H): High, indicating the vulnerability affects components beyond its security scope.
• Scope Integrity (SI:L): Low, suggesting minimal integrity impact within the changed scope.
• Scope Availability (SA:N): None, indicating no availability impact within the changed scope.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves an attacker registering the unclaimed S3 bucket (onelogin-adc-logs-production). Once registered, the attacker can receive log files from other OneLogin tenants. These logs may contain sensitive data such as directory tokens, user metadata, and environment configuration. Potential exploitation methods include:

• Cross-Tenant Data Leakage: An attacker can access sensitive information from multiple tenants, leading to data breaches.
• JWT Signing Key Recovery: If the logs contain JWT signing keys, an attacker can recover these keys and impersonate users.
• User Impersonation: With access to user metadata and tokens, an attacker can impersonate legitimate users, leading to unauthorized access and potential data exfiltration.

3. Affected Systems and Software Versions

The vulnerability affects the OneLogin Active Directory Connector (ADC) versions prior to 6.1.5. Organizations using these versions are at risk and should prioritize updates or patches.

4. Recommended Mitigation Strategies

To mitigate this vulnerability, the following strategies are recommended:

• Update Software: Immediately update the OneLogin AD Connector to version 6.1.5 or later.
• Validate Bucket Ownership: Ensure that all S3 buckets used for logging are properly validated and owned by the organization.
• Monitor Logs: Implement robust monitoring and alerting for any unauthorized access attempts to S3 buckets.
• Access Controls: Enforce strict access controls and authentication mechanisms for all cloud resources.
• Regular Audits: Conduct regular security audits and vulnerability assessments to identify and remediate similar misconfigurations.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to European organizations using OneLogin AD Connector, particularly those handling sensitive data. The potential for cross-tenant data leakage and user impersonation can lead to severe data breaches, financial losses, and reputational damage. Compliance with regulations such as GDPR may also be compromised, leading to legal repercussions.

6. Technical Details for Security Professionals

• Detection: Implement intrusion detection systems (IDS) and intrusion prevention systems (IPS) to monitor for unauthorized access to S3 buckets.
• Logging and Monitoring: Ensure comprehensive logging and monitoring of all cloud infrastructure components, with a focus on S3 bucket access and data transfers.
• Incident Response: Develop and maintain an incident response plan that includes steps for identifying, containing, and remediating cloud infrastructure misconfigurations.
• Patch Management: Establish a robust patch management process to ensure timely updates and patches for all software components, including third-party integrations.
• Security Training: Provide regular training for IT and security personnel on best practices for cloud security and infrastructure management.

By addressing these points, organizations can significantly reduce the risk associated with this vulnerability and enhance their overall cybersecurity posture.