CVE-2023-36826: Unauthorized Access to Debug and Artifact Bundles in Sentry Versions 8.21. to 23.5.1

Sentry is a popular error tracking and performance monitoring platform, actively used by software development teams across the globe. However, a recent vulnerability affecting the platform has come to light. Dubbed as 'CVE-2023-36826,' this security flaw allows authenticated users to download debug or artifact bundles from arbitrary organizations and projects without having the necessary permissions. This post provides an in-depth analysis of the vulnerability, the code that exposes the flaw, links to original references, suggested mitigation measures, and details on the exploit.

Vulnerability Details

The vulnerability, identified as CVE-2023-36826, impacts Sentry versions starting with 8.21. and prior to 23.5.2. A user authenticated with Sentry can exploit this flaw by downloading debug or artifact bundles without needing to be a member of the organization or having sufficient permission levels on the project. Essentially, this means that the user could potentially gain access to sensitive information, browse the project's source code, and potentially cause further harm.

Code Snippet

The vulnerable code in question is the API endpoint responsible for serving debug and artifact bundle downloads. A simplified version of the problematic code snippet looks like this:

@api_route('/projects/{org_slug}/{proj_slug}/files/{file_id}/', methods=['GET'])
@authenticated()
def download_debug_file(request, org_slug, proj_slug, file_id):
    file = DebugFile.objects.get(id=file_id)
    return _download_file(file)

As visible from the code, while it does require authentication, it lacks proper authorization checks to determine if the authenticated user should indeed have access to the requested file.

Original References

- Sentry Changelog detailing the vulnerability and fix
- Sentry Security Advisory

Exploit Details

An exploit of CVE-2023-36826 would involve an authenticated user accessing the vulnerable API endpoint with a known debug or artifact bundle ID. This could be done via any tool capable of making HTTP requests like curl or Postman, or even through the user's browser. Once the exploit is successfully executed, the user would have unauthorized access to data they otherwise wouldn't have been able to view or download.

Mitigation Measures

To address this security flaw, Sentry issued a patch in version 23.5.2, ensuring proper authorization checks are scoped on requests to retrieve debug or artifact bundles. As a result, authenticated users with insufficient permissions on a specific project can no longer download debug or artifact bundles.

For Sentry SaaS users, no action is required, as the platform would have automatically updated to the patched version. However, Self-Hosted Sentry users are advised to upgrade their deployments to version 23.5.2 or higher to secure their environments against this vulnerability.

Conclusion

CVE-2023-36826 highlights the importance of robust permission checking in web applications. While Sentry has addressed the issue promptly with a patch, it is crucial for users of Self-Hosted Sentry to remain vigilant and stay updated with the latest releases to safeguard their environments.

Timeline

Published on: 07/25/2023 19:15:00 UTC
Last modified on: 08/02/2023 15:57:00 UTC