CVE-2024-6863 is a vulnerability classified under CWE-749 (Exposed Dangerous Method or Function) found in the h2oai/h2o-3 machine learning platform, specifically version 3.46.0. The flaw arises from an exposed endpoint that provides access to a custom EncryptionTool. This tool allows an attacker to remotely encrypt arbitrary files on the target server using an encryption key of their choosing. Furthermore, the attacker can overwrite existing keys, effectively locking out legitimate users from decrypting their own files. The vulnerability requires no authentication (PR:N) and no user interaction (UI:N), making it highly accessible for remote exploitation over the network (AV:N). The CVSS v3.0 score of 6.5 reflects a medium severity, primarily due to the impact on integrity and availability without compromising confidentiality. The encryption of arbitrary files can disrupt business operations by causing data loss or forcing costly recovery efforts, akin to ransomware attacks. No patches or known exploits are currently documented, but the potential for misuse is significant given the nature of the exposed functionality. The vulnerability highlights a critical design flaw where dangerous methods are exposed without proper access controls, violating secure coding best practices. Organizations deploying h2oai/h2o-3 should urgently assess exposure and implement controls to prevent exploitation.

For European organizations, the impact of CVE-2024-6863 can be severe, especially for those relying on h2oai/h2o-3 for AI, data analytics, or machine learning workloads. Successful exploitation can lead to unauthorized encryption of critical files, causing data integrity loss and operational downtime. This ransomware-like behavior can disrupt services, delay projects, and incur significant recovery costs. The inability to recover encrypted files without the attacker’s key can lead to permanent data loss or force organizations to pay ransoms. Industries with high data sensitivity such as finance, healthcare, and critical infrastructure are particularly vulnerable. The medium CVSS score underestimates the potential operational impact if exploited at scale. Additionally, the lack of authentication requirements increases the attack surface, making it easier for threat actors to target exposed servers remotely. European organizations with limited incident response capabilities or those lacking proper network segmentation may face amplified risks. The reputational damage and regulatory consequences under GDPR for data unavailability or loss further exacerbate the impact.

1. Immediately restrict network access to the vulnerable EncryptionTool endpoint using firewall rules or network segmentation to limit exposure to trusted administrators only. 2. Implement strict authentication and authorization controls around all encryption-related functionalities to prevent unauthorized use. 3. Monitor logs and network traffic for unusual encryption activity or access patterns indicative of exploitation attempts. 4. If possible, disable or remove the exposed EncryptionTool endpoint until a vendor patch or update is available. 5. Regularly back up critical data and verify backup integrity to ensure recovery capability in case of encryption incidents. 6. Engage with h2oai vendor support to obtain patches or mitigations as they become available. 7. Conduct security code reviews and penetration testing focused on exposed APIs and endpoints to identify similar dangerous exposures. 8. Educate system administrators and security teams about this vulnerability and the importance of controlling access to encryption tools. 9. Deploy endpoint detection and response (EDR) solutions capable of detecting anomalous file encryption behaviors. 10. Consider applying application-layer firewalls or API gateways that can enforce granular access policies on exposed services.