H2O, Arbitrary File Overwrite, CVE-2025-12345 (High)

How the CVE Works:

In H2O version 3.46.0, the model export functionality lacks proper validation of the file path provided during the export process. This allows an attacker to specify an arbitrary file path on the server’s filesystem. When the model is exported, it overwrites the file at the specified location. Although the attacker cannot control the content of the overwritten file (as it is a trained model), this vulnerability can still lead to denial of service, corruption of critical system files, or disruption of server operations. The issue stems from insufficient sanitization of user-supplied input in the export endpoint, making it possible to traverse directories and overwrite files outside the intended export directory.

DailyCVE Form:

Platform: H2O
Version: 3.46.0
Vulnerability: Arbitrary File Overwrite
Severity: High
Date: Mar 20, 2025

What Undercode Say:

Exploitation:

1. Crafting the Payload: An attacker can exploit this vulnerability by sending a specially crafted request to the model export endpoint, specifying a target file path (e.g., `/etc/passwd` or critical system files).

   curl -X POST http://<target>/export -d '{"model_id": "example", "path": "../../../../etc/passwd"}'
   

2. Overwriting Files: The server will overwrite the specified file with the exported model, potentially disrupting system functionality.

Protection:

1. Input Validation: Implement strict validation of file paths to prevent directory traversal.

   import os
   def sanitize_path(user_input):
   base_dir = "/safe/export/directory"
   full_path = os.path.abspath(os.path.join(base_dir, user_input))
   if not full_path.startswith(base_dir):
   raise ValueError("Invalid file path")
   return full_path
   

2. File Permissions: Restrict write permissions to critical directories and ensure the export directory is isolated.

   chmod 750 /safe/export/directory
   

3. Patch Update: Upgrade to a patched version of H2O (if available) or apply a temporary fix by disabling the export functionality until a patch is released.

Detection:

1. Log Monitoring: Monitor server logs for unusual export requests or repeated attempts to access sensitive paths.

   grep "export" /var/log/h2o/access.log | grep "../"
   

2. File Integrity Checks: Use tools like `tripwire` or `aide` to detect unauthorized file modifications.

   aide --check
   

Mitigation:

1. Web Application Firewall (WAF): Deploy a WAF to block malicious requests containing directory traversal patterns.

   location /export {
   if ($request_uri ~ "../") {
   return 403;
   }
   }
   

2. Disable Export Endpoint: Temporarily disable the export endpoint if not in use.

   sudo ufw deny out 54321
   

References:

• bash
• bash
  By following these steps, organizations can mitigate the risk posed by this vulnerability and protect their H2O deployments from exploitation.

References:

Reported By: https://github.com/advisories/GHSA-47f6-5p7h-5f3h
Extra Source Hub:
Undercode

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