Executive Summary

The Frontend File Manager Plugin for WordPress, version 23.6 or below, has a vulnerability due to improper nonce verification in its file download handler.

This flaw allows unauthenticated attackers to download files uploaded by any user by iterating through file identifiers without needing to log in or have permission.

Specifically, attackers can send a request with certain parameters that bypass security checks, enabling them to access files they should not be able to.

This vulnerability is classified as an Insecure Direct Object Reference (IDOR), which falls under OWASP's Broken Access Control category.

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Impact Analysis

This vulnerability can lead to unauthorized disclosure of sensitive or private files uploaded by users.

Attackers can download any file by iterating through file identifiers without authentication, potentially exposing confidential information.

Such unauthorized access can compromise user privacy, damage trust, and lead to data breaches.

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Detection Guidance

This vulnerability can be detected by attempting to send HTTP requests to the WordPress site using the Frontend File Manager Plugin with the specific parameters that trigger the file download handler without authentication.

A typical detection command would involve sending a request with the parameters `do=wpfm_download`, a valid or guessed `file_id`, and `nm_file_by_email=1` to check if files can be downloaded without proper authorization.

• Use curl or similar tools to send requests like: curl -G 'http://targetsite.com/wp-admin/admin-ajax.php' --data-urlencode 'do=wpfm_download' --data-urlencode 'file_id=1' --data-urlencode 'nm_file_by_email=1'
• Iterate over different file_id values to see if files can be downloaded without authentication, indicating the presence of the vulnerability.

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Mitigation Strategies

Since no known fix exists at the time of reporting, immediate mitigation steps include restricting access to the Frontend File Manager Plugin's file download handler.

• Implement web application firewall (WAF) rules to block requests containing the parameters `do=wpfm_download` and `nm_file_by_email=1` from unauthenticated users.
• Restrict access to the plugin's endpoints by IP address or require authentication before allowing file downloads.
• Monitor logs for suspicious requests attempting to exploit the file download handler.

Additionally, plan to update the plugin once a patch or fixed version is released.

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Compliance Impact

The vulnerability allows unauthenticated attackers to download files uploaded by any user due to improper nonce verification, leading to unauthorized access to potentially sensitive user data.

Such unauthorized access to user files can result in violations of data protection regulations like GDPR and HIPAA, which require strict controls over personal and sensitive information to prevent unauthorized disclosure.

Because the flaw is an Insecure Direct Object Reference (IDOR) under OWASP's Broken Access Control category, it indicates a failure in access control mechanisms, which is critical for compliance with these standards.

Therefore, exploitation of this vulnerability could lead to non-compliance with regulations that mandate confidentiality and integrity of user data.

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