H2O Remote Code Execution via POJO Model Import

The impact of CVE-2023-6016 is severe. Successful exploitation allows an attacker to gain complete control over the affected server. This includes the ability to execute arbitrary commands, access sensitive data (such as training datasets and model artifacts), and potentially pivot to other systems on the network. The POJO model import feature, designed for convenient model deployment, becomes a critical attack vector. This vulnerability shares similarities with other deserialization vulnerabilities where malicious payloads can be injected into imported objects, leading to arbitrary code execution. The blast radius extends to any system accessible from the compromised H2O server.

Organizations heavily reliant on H2O for machine learning tasks, particularly those exposing the H2O dashboard to external networks or untrusted users, are at significant risk. Environments where model import functionality is frequently used, especially with models sourced from external providers, are also particularly vulnerable. Legacy H2O deployments that have not been regularly updated are at heightened risk.

• java / server: Monitor H2O server logs for suspicious activity related to model imports. Look for errors or unusual processes being spawned.

journalctl -u h2o -f | grep -i "error" 

• java / supply-chain: Examine any third-party libraries or dependencies used by the H2O server for potential vulnerabilities. • generic web: Monitor network traffic to the H2O dashboard for unusual requests or data uploads. • java / server: Use a Java profiler to monitor memory usage and identify potential deserialization vulnerabilities.

1. 2023-11-16Disclosure

   disclosure

1. Reserviert2023-11-08
2. Veröffentlicht2023-11-16
3. Geändert2024-08-02
4. EPSS aktualisiert2026-04-02

The primary mitigation for CVE-2023-6016 is to upgrade to a patched version of H2O as soon as possible. If immediate patching is not feasible, consider disabling the POJO model import feature entirely, as this eliminates the attack vector. Implement strict input validation on any data imported into H2O, particularly when dealing with external sources. Network segmentation can limit the potential impact of a successful exploit by restricting access to the H2O server. After upgrading, verify the fix by attempting to import a known malicious POJO model and confirming that it is rejected or handled safely without code execution.