Authenticated User Theme Overwrite in TDuck Survey Form

Executive Summary

This vulnerability is an insecure direct object reference flaw in TDuck survey form versions up to 6.0. It allows authenticated users to overwrite other users' form themes by submitting another user's sequential theme ID with their own form key. Attackers can change colors, image URLs, or remove the victim's theme entirely.

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Detection Guidance

Monitor POST requests to /user/form/theme/save endpoints for unauthorized theme ID submissions. Check for multiple form themes associated with a single user account or unexpected theme modifications. Review application logs for sequential theme ID manipulation attempts.

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Impact Analysis

If exploited, this vulnerability could allow attackers to modify or delete your form themes, potentially disrupting your survey forms' appearance and functionality. It requires an attacker to have an account or valid token, but could lead to unauthorized theme changes.

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Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by enabling unauthorized users to modify or delete form themes belonging to other users. This may lead to unauthorized access or disclosure of sensitive form data, violating data integrity and confidentiality requirements under these regulations.

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Mitigation Strategies

Update tduck-survey-form to the latest version beyond 6.0. Implement strict authorization checks to prevent users from modifying themes not owned by them. Validate theme IDs against user ownership in the saveFormTheme handler.

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