CVE-2025-25015 - Prototype Pollution in Kibana Leads to Arbitrary Code Execution

In this post, we will discuss a critical vulnerability in Kibana (CVE-2025-25015) that enables arbitrary code execution through a crafted file upload and a sequence of specifically crafted HTTP requests. Kibana is a widely-used open-source data visualization and exploration tool that works in conjunction with Elasticsearch.

This vulnerability affects Kibana versions >= 8.15. and < 8.17.1 for users with the Viewer role. In Kibana versions 8.17.1 and 8.17.2, the exploit is only possible for users with roles containing the following privileges: fleet-all, integrations-all, actions:execute-advanced-connectors.

Explanation of the Prototype Pollution Vulnerability

Prototype pollution is a form of vulnerability that occurs when an application allows an attacker to modify an object's prototype. This can result in unintended consequences, such as unauthorized access, privilege escalation, or arbitrary code execution.

In the case of Kibana, an attacker can exploit this vulnerability by crafting a malicious file and sending specific HTTP requests, leading to arbitrary code execution on the server-side.

Exploit Details

The exploit starts with the creation of a malicious file, specifically a crafted JSON file. The attacker then proceeds to upload this file to the Kibana server. The JSON content will look like this:

{
  "__proto__": {
    "exec": "require('child_process').execSync('YOUR COMMAND HERE')"
  }
}

Replace 'YOUR COMMAND HERE' with the command you want to execute on the server.

Once the JSON file is uploaded, the attacker sends a series of specifically crafted HTTP requests to the Kibana server. The exact HTTP requests required to trigger the vulnerability will vary depending on the Kibana version and the user's privileges.

For Kibana versions >= 8.15. and < 8.17.1, users with the Viewer role can already exploit this vulnerability. The following example demonstrates the HTTP requests required in this case:

POST /api/saved_objects/action
Content-Type: application/json
kbn-xsrf: true

{
  "type": "dashboard",
  "attributes": {
    "title": "__proto__"
  },
  "id": "ArbitraryID"
}

For Kibana versions 8.17.1 and 8.17.2, users need a specific set of privileges (fleet-all, integrations-all, actions:execute-advanced-connectors) to exploit this vulnerability. The HTTP requests needed to exploit this vulnerability in these versions will be different.

Mitigation and Remediation

Users are advised to update their Kibana instances to the latest version, as this vulnerability has been patched in version 8.17.3. The patch can be found at the official Kibana repository.

Additionally, administrators should restrict access to sensitive roles and privileges, follow the principle of least privilege, and monitor their Kibana instances for any suspicious activities.

Lastly, developers can use appropriate security mechanisms, like input validation and proper access_control, to prevent prototype pollution attacks.

Original References

- Elastic Blog Post
- CVE-2025-25015 Details
- Kibana GitHub Repository

Conclusion

CVE-2025-25015 is a critical vulnerability that impacts certain versions of Kibana and allows for arbitrary code execution via a crafted file upload and carefully crafted HTTP requests. Users are encouraged to update their instances to the latest version to mitigate this security risk and follow best security practices to further protect their systems.

Timeline

Published on: 03/05/2025 10:15:20 UTC