Executive Summary

This vulnerability is an authorization flaw in the MISP Event Template Importer overwrite workflow. When a user imports an event template in overwrite mode, the system checked if a matching template existed but did not verify if the user belonged to the organization that owned the existing template.

As a result, an authenticated user with access to the template import functionality could overwrite an event template owned by another organization without proper authorization.

Site administrators are exempt from this restriction and can overwrite templates across organizations. The issue was fixed by adding an ownership check that restricts non-site-admin users to only overwrite templates owned by their own organization.

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Compliance Impact

This vulnerability allows an authenticated user to overwrite event templates owned by other organizations without proper authorization. Such unauthorized modification of data could lead to integrity and confidentiality issues within the affected system.

While the provided information does not explicitly mention compliance with standards like GDPR or HIPAA, unauthorized data modification and lack of proper access controls can potentially violate requirements related to data integrity, access control, and accountability found in these regulations.

The fix enforces ownership checks before allowing template overwrites, which helps restore proper access control and reduces the risk of unauthorized data changes, thereby supporting compliance efforts.

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Impact Analysis

Successful exploitation of this vulnerability allows an unauthorized user to modify another organization's event template.

This could lead to changes in the template structure, attributes, or metadata that are used in subsequent event creation or sharing workflows, potentially causing misinformation, data integrity issues, or disruption in collaborative processes.

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Detection Guidance

Detection of this vulnerability involves monitoring attempts to overwrite event templates owned by other organizations without proper authorization.

Specifically, you should look for error messages or logs indicating failed overwrite attempts with messages such as "Cannot overwrite template owned by another org."

Commands or methods to detect this might include reviewing application logs for such error messages or monitoring API calls related to event template imports in overwrite mode.

Since the vulnerability is related to authorization checks during template overwrite, checking audit logs for unexpected template modifications by users outside the owning organization can also help detect exploitation attempts.

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Mitigation Strategies

To mitigate this vulnerability immediately, ensure that your MISP instance is updated with the patch that enforces ownership checks before allowing template overwrites.

The fix requires that non-site-admin users can only overwrite templates owned by their own organization, blocking unauthorized overwrite attempts.

If updating immediately is not possible, restrict access to the template import overwrite functionality to trusted users or site administrators only.

Additionally, monitor and audit template overwrite activities to detect any unauthorized attempts.

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